diff --git a/crypto.c b/crypto.c deleted file mode 100644 index 7f09ead..0000000 --- a/crypto.c +++ /dev/null @@ -1,21 +0,0 @@ -#include "crypto.h" -#include "monocypher.h" -#include -#include - -static uint8_t sk[64]; -static uint8_t pk[32]; -static uint8_t seed[32]; - -static uint8_t signature[64]; - -void crypto_demo(void) { - crypto_eddsa_key_pair(sk, pk, seed); - char *msg = "Hello\n"; - - crypto_eddsa_sign(signature, sk, (uint8_t *)msg, 6); - int res = crypto_eddsa_check(signature, pk, (uint8_t *)msg, 6); - - crypto_wipe(sk, 64); - crypto_wipe(pk, 32); -} diff --git a/crypto.h b/crypto.h deleted file mode 100644 index f93f914..0000000 --- a/crypto.h +++ /dev/null @@ -1,3 +0,0 @@ -#pragma once - -void crypto_demo(void); diff --git a/monocypher-ed25519.c b/monocypher-ed25519.c deleted file mode 100644 index 1dbcfbb..0000000 --- a/monocypher-ed25519.c +++ /dev/null @@ -1,500 +0,0 @@ -// Monocypher version 4.0.2 -// -// This file is dual-licensed. Choose whichever licence you want from -// the two licences listed below. -// -// The first licence is a regular 2-clause BSD licence. The second licence -// is the CC-0 from Creative Commons. It is intended to release Monocypher -// to the public domain. The BSD licence serves as a fallback option. -// -// SPDX-License-Identifier: BSD-2-Clause OR CC0-1.0 -// -// ------------------------------------------------------------------------ -// -// Copyright (c) 2017-2019, Loup Vaillant -// All rights reserved. -// -// -// Redistribution and use in source and binary forms, with or without -// modification, are permitted provided that the following conditions are -// met: -// -// 1. Redistributions of source code must retain the above copyright -// notice, this list of conditions and the following disclaimer. -// -// 2. Redistributions in binary form must reproduce the above copyright -// notice, this list of conditions and the following disclaimer in the -// documentation and/or other materials provided with the -// distribution. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -// -// ------------------------------------------------------------------------ -// -// Written in 2017-2019 by Loup Vaillant -// -// To the extent possible under law, the author(s) have dedicated all copyright -// and related neighboring rights to this software to the public domain -// worldwide. This software is distributed without any warranty. -// -// You should have received a copy of the CC0 Public Domain Dedication along -// with this software. If not, see -// - -#include "monocypher-ed25519.h" - -#ifdef MONOCYPHER_CPP_NAMESPACE -namespace MONOCYPHER_CPP_NAMESPACE { -#endif - -///////////////// -/// Utilities /// -///////////////// -#define FOR(i, min, max) for (size_t i = min; i < max; i++) -#define COPY(dst, src, size) FOR(_i_, 0, size) (dst)[_i_] = (src)[_i_] -#define ZERO(buf, size) FOR(_i_, 0, size) (buf)[_i_] = 0 -#define WIPE_CTX(ctx) crypto_wipe(ctx , sizeof(*(ctx))) -#define WIPE_BUFFER(buffer) crypto_wipe(buffer, sizeof(buffer)) -#define MIN(a, b) ((a) <= (b) ? (a) : (b)) -typedef uint8_t u8; -typedef uint64_t u64; - -// Returns the smallest positive integer y such that -// (x + y) % pow_2 == 0 -// Basically, it's how many bytes we need to add to "align" x. -// Only works when pow_2 is a power of 2. -// Note: we use ~x+1 instead of -x to avoid compiler warnings -static size_t align(size_t x, size_t pow_2) -{ - return (~x + 1) & (pow_2 - 1); -} - -static u64 load64_be(const u8 s[8]) -{ - return((u64)s[0] << 56) - | ((u64)s[1] << 48) - | ((u64)s[2] << 40) - | ((u64)s[3] << 32) - | ((u64)s[4] << 24) - | ((u64)s[5] << 16) - | ((u64)s[6] << 8) - | (u64)s[7]; -} - -static void store64_be(u8 out[8], u64 in) -{ - out[0] = (in >> 56) & 0xff; - out[1] = (in >> 48) & 0xff; - out[2] = (in >> 40) & 0xff; - out[3] = (in >> 32) & 0xff; - out[4] = (in >> 24) & 0xff; - out[5] = (in >> 16) & 0xff; - out[6] = (in >> 8) & 0xff; - out[7] = in & 0xff; -} - -static void load64_be_buf (u64 *dst, const u8 *src, size_t size) { - FOR(i, 0, size) { dst[i] = load64_be(src + i*8); } -} - -/////////////// -/// SHA 512 /// -/////////////// -static u64 rot(u64 x, int c ) { return (x >> c) | (x << (64 - c)); } -static u64 ch (u64 x, u64 y, u64 z) { return (x & y) ^ (~x & z); } -static u64 maj(u64 x, u64 y, u64 z) { return (x & y) ^ ( x & z) ^ (y & z); } -static u64 big_sigma0(u64 x) { return rot(x, 28) ^ rot(x, 34) ^ rot(x, 39); } -static u64 big_sigma1(u64 x) { return rot(x, 14) ^ rot(x, 18) ^ rot(x, 41); } -static u64 lit_sigma0(u64 x) { return rot(x, 1) ^ rot(x, 8) ^ (x >> 7); } -static u64 lit_sigma1(u64 x) { return rot(x, 19) ^ rot(x, 61) ^ (x >> 6); } - -static const u64 K[80] = { - 0x428a2f98d728ae22,0x7137449123ef65cd,0xb5c0fbcfec4d3b2f,0xe9b5dba58189dbbc, - 0x3956c25bf348b538,0x59f111f1b605d019,0x923f82a4af194f9b,0xab1c5ed5da6d8118, - 0xd807aa98a3030242,0x12835b0145706fbe,0x243185be4ee4b28c,0x550c7dc3d5ffb4e2, - 0x72be5d74f27b896f,0x80deb1fe3b1696b1,0x9bdc06a725c71235,0xc19bf174cf692694, - 0xe49b69c19ef14ad2,0xefbe4786384f25e3,0x0fc19dc68b8cd5b5,0x240ca1cc77ac9c65, - 0x2de92c6f592b0275,0x4a7484aa6ea6e483,0x5cb0a9dcbd41fbd4,0x76f988da831153b5, - 0x983e5152ee66dfab,0xa831c66d2db43210,0xb00327c898fb213f,0xbf597fc7beef0ee4, - 0xc6e00bf33da88fc2,0xd5a79147930aa725,0x06ca6351e003826f,0x142929670a0e6e70, - 0x27b70a8546d22ffc,0x2e1b21385c26c926,0x4d2c6dfc5ac42aed,0x53380d139d95b3df, - 0x650a73548baf63de,0x766a0abb3c77b2a8,0x81c2c92e47edaee6,0x92722c851482353b, - 0xa2bfe8a14cf10364,0xa81a664bbc423001,0xc24b8b70d0f89791,0xc76c51a30654be30, - 0xd192e819d6ef5218,0xd69906245565a910,0xf40e35855771202a,0x106aa07032bbd1b8, - 0x19a4c116b8d2d0c8,0x1e376c085141ab53,0x2748774cdf8eeb99,0x34b0bcb5e19b48a8, - 0x391c0cb3c5c95a63,0x4ed8aa4ae3418acb,0x5b9cca4f7763e373,0x682e6ff3d6b2b8a3, - 0x748f82ee5defb2fc,0x78a5636f43172f60,0x84c87814a1f0ab72,0x8cc702081a6439ec, - 0x90befffa23631e28,0xa4506cebde82bde9,0xbef9a3f7b2c67915,0xc67178f2e372532b, - 0xca273eceea26619c,0xd186b8c721c0c207,0xeada7dd6cde0eb1e,0xf57d4f7fee6ed178, - 0x06f067aa72176fba,0x0a637dc5a2c898a6,0x113f9804bef90dae,0x1b710b35131c471b, - 0x28db77f523047d84,0x32caab7b40c72493,0x3c9ebe0a15c9bebc,0x431d67c49c100d4c, - 0x4cc5d4becb3e42b6,0x597f299cfc657e2a,0x5fcb6fab3ad6faec,0x6c44198c4a475817 -}; - -static void sha512_compress(crypto_sha512_ctx *ctx) -{ - u64 a = ctx->hash[0]; u64 b = ctx->hash[1]; - u64 c = ctx->hash[2]; u64 d = ctx->hash[3]; - u64 e = ctx->hash[4]; u64 f = ctx->hash[5]; - u64 g = ctx->hash[6]; u64 h = ctx->hash[7]; - - FOR (j, 0, 16) { - u64 in = K[j] + ctx->input[j]; - u64 t1 = big_sigma1(e) + ch (e, f, g) + h + in; - u64 t2 = big_sigma0(a) + maj(a, b, c); - h = g; g = f; f = e; e = d + t1; - d = c; c = b; b = a; a = t1 + t2; - } - size_t i16 = 0; - FOR(i, 1, 5) { - i16 += 16; - FOR (j, 0, 16) { - ctx->input[j] += lit_sigma1(ctx->input[(j- 2) & 15]); - ctx->input[j] += lit_sigma0(ctx->input[(j-15) & 15]); - ctx->input[j] += ctx->input[(j- 7) & 15]; - u64 in = K[i16 + j] + ctx->input[j]; - u64 t1 = big_sigma1(e) + ch (e, f, g) + h + in; - u64 t2 = big_sigma0(a) + maj(a, b, c); - h = g; g = f; f = e; e = d + t1; - d = c; c = b; b = a; a = t1 + t2; - } - } - - ctx->hash[0] += a; ctx->hash[1] += b; - ctx->hash[2] += c; ctx->hash[3] += d; - ctx->hash[4] += e; ctx->hash[5] += f; - ctx->hash[6] += g; ctx->hash[7] += h; -} - -// Write 1 input byte -static void sha512_set_input(crypto_sha512_ctx *ctx, u8 input) -{ - size_t word = ctx->input_idx >> 3; - size_t byte = ctx->input_idx & 7; - ctx->input[word] |= (u64)input << (8 * (7 - byte)); -} - -// Increment a 128-bit "word". -static void sha512_incr(u64 x[2], u64 y) -{ - x[1] += y; - if (x[1] < y) { - x[0]++; - } -} - -void crypto_sha512_init(crypto_sha512_ctx *ctx) -{ - ctx->hash[0] = 0x6a09e667f3bcc908; - ctx->hash[1] = 0xbb67ae8584caa73b; - ctx->hash[2] = 0x3c6ef372fe94f82b; - ctx->hash[3] = 0xa54ff53a5f1d36f1; - ctx->hash[4] = 0x510e527fade682d1; - ctx->hash[5] = 0x9b05688c2b3e6c1f; - ctx->hash[6] = 0x1f83d9abfb41bd6b; - ctx->hash[7] = 0x5be0cd19137e2179; - ctx->input_size[0] = 0; - ctx->input_size[1] = 0; - ctx->input_idx = 0; - ZERO(ctx->input, 16); -} - -void crypto_sha512_update(crypto_sha512_ctx *ctx, - const u8 *message, size_t message_size) -{ - // Avoid undefined NULL pointer increments with empty messages - if (message_size == 0) { - return; - } - - // Align ourselves with word boundaries - if ((ctx->input_idx & 7) != 0) { - size_t nb_bytes = MIN(align(ctx->input_idx, 8), message_size); - FOR (i, 0, nb_bytes) { - sha512_set_input(ctx, message[i]); - ctx->input_idx++; - } - message += nb_bytes; - message_size -= nb_bytes; - } - - // Align ourselves with block boundaries - if ((ctx->input_idx & 127) != 0) { - size_t nb_words = MIN(align(ctx->input_idx, 128), message_size) >> 3; - load64_be_buf(ctx->input + (ctx->input_idx >> 3), message, nb_words); - ctx->input_idx += nb_words << 3; - message += nb_words << 3; - message_size -= nb_words << 3; - } - - // Compress block if needed - if (ctx->input_idx == 128) { - sha512_incr(ctx->input_size, 1024); // size is in bits - sha512_compress(ctx); - ctx->input_idx = 0; - ZERO(ctx->input, 16); - } - - // Process the message block by block - FOR (i, 0, message_size >> 7) { // number of blocks - load64_be_buf(ctx->input, message, 16); - sha512_incr(ctx->input_size, 1024); // size is in bits - sha512_compress(ctx); - ctx->input_idx = 0; - ZERO(ctx->input, 16); - message += 128; - } - message_size &= 127; - - if (message_size != 0) { - // Remaining words - size_t nb_words = message_size >> 3; - load64_be_buf(ctx->input, message, nb_words); - ctx->input_idx += nb_words << 3; - message += nb_words << 3; - message_size -= nb_words << 3; - - // Remaining bytes - FOR (i, 0, message_size) { - sha512_set_input(ctx, message[i]); - ctx->input_idx++; - } - } -} - -void crypto_sha512_final(crypto_sha512_ctx *ctx, u8 hash[64]) -{ - // Add padding bit - if (ctx->input_idx == 0) { - ZERO(ctx->input, 16); - } - sha512_set_input(ctx, 128); - - // Update size - sha512_incr(ctx->input_size, ctx->input_idx * 8); - - // Compress penultimate block (if any) - if (ctx->input_idx > 111) { - sha512_compress(ctx); - ZERO(ctx->input, 14); - } - // Compress last block - ctx->input[14] = ctx->input_size[0]; - ctx->input[15] = ctx->input_size[1]; - sha512_compress(ctx); - - // Copy hash to output (big endian) - FOR (i, 0, 8) { - store64_be(hash + i*8, ctx->hash[i]); - } - - WIPE_CTX(ctx); -} - -void crypto_sha512(u8 hash[64], const u8 *message, size_t message_size) -{ - crypto_sha512_ctx ctx; - crypto_sha512_init (&ctx); - crypto_sha512_update(&ctx, message, message_size); - crypto_sha512_final (&ctx, hash); -} - -//////////////////// -/// HMAC SHA 512 /// -//////////////////// -void crypto_sha512_hmac_init(crypto_sha512_hmac_ctx *ctx, - const u8 *key, size_t key_size) -{ - // hash key if it is too long - if (key_size > 128) { - crypto_sha512(ctx->key, key, key_size); - key = ctx->key; - key_size = 64; - } - // Compute inner key: padded key XOR 0x36 - FOR (i, 0, key_size) { ctx->key[i] = key[i] ^ 0x36; } - FOR (i, key_size, 128) { ctx->key[i] = 0x36; } - // Start computing inner hash - crypto_sha512_init (&ctx->ctx); - crypto_sha512_update(&ctx->ctx, ctx->key, 128); -} - -void crypto_sha512_hmac_update(crypto_sha512_hmac_ctx *ctx, - const u8 *message, size_t message_size) -{ - crypto_sha512_update(&ctx->ctx, message, message_size); -} - -void crypto_sha512_hmac_final(crypto_sha512_hmac_ctx *ctx, u8 hmac[64]) -{ - // Finish computing inner hash - crypto_sha512_final(&ctx->ctx, hmac); - // Compute outer key: padded key XOR 0x5c - FOR (i, 0, 128) { - ctx->key[i] ^= 0x36 ^ 0x5c; - } - // Compute outer hash - crypto_sha512_init (&ctx->ctx); - crypto_sha512_update(&ctx->ctx, ctx->key , 128); - crypto_sha512_update(&ctx->ctx, hmac, 64); - crypto_sha512_final (&ctx->ctx, hmac); // outer hash - WIPE_CTX(ctx); -} - -void crypto_sha512_hmac(u8 hmac[64], const u8 *key, size_t key_size, - const u8 *message, size_t message_size) -{ - crypto_sha512_hmac_ctx ctx; - crypto_sha512_hmac_init (&ctx, key, key_size); - crypto_sha512_hmac_update(&ctx, message, message_size); - crypto_sha512_hmac_final (&ctx, hmac); -} - -//////////////////// -/// HKDF SHA 512 /// -//////////////////// -void crypto_sha512_hkdf_expand(u8 *okm, size_t okm_size, - const u8 *prk, size_t prk_size, - const u8 *info, size_t info_size) -{ - int not_first = 0; - u8 ctr = 1; - u8 blk[64]; - - while (okm_size > 0) { - size_t out_size = MIN(okm_size, sizeof(blk)); - - crypto_sha512_hmac_ctx ctx; - crypto_sha512_hmac_init(&ctx, prk , prk_size); - if (not_first) { - // For some reason HKDF uses some kind of CBC mode. - // For some reason CTR mode alone wasn't enough. - // Like what, they didn't trust HMAC in 2010? Really?? - crypto_sha512_hmac_update(&ctx, blk , sizeof(blk)); - } - crypto_sha512_hmac_update(&ctx, info, info_size); - crypto_sha512_hmac_update(&ctx, &ctr, 1); - crypto_sha512_hmac_final(&ctx, blk); - - COPY(okm, blk, out_size); - - not_first = 1; - okm += out_size; - okm_size -= out_size; - ctr++; - } -} - -void crypto_sha512_hkdf(u8 *okm , size_t okm_size, - const u8 *ikm , size_t ikm_size, - const u8 *salt, size_t salt_size, - const u8 *info, size_t info_size) -{ - // Extract - u8 prk[64]; - crypto_sha512_hmac(prk, salt, salt_size, ikm, ikm_size); - - // Expand - crypto_sha512_hkdf_expand(okm, okm_size, prk, sizeof(prk), info, info_size); -} - -/////////////// -/// Ed25519 /// -/////////////// -void crypto_ed25519_key_pair(u8 secret_key[64], u8 public_key[32], u8 seed[32]) -{ - u8 a[64]; - COPY(a, seed, 32); // a[ 0..31] = seed - crypto_wipe(seed, 32); - COPY(secret_key, a, 32); // secret key = seed - crypto_sha512(a, a, 32); // a[ 0..31] = scalar - crypto_eddsa_trim_scalar(a, a); // a[ 0..31] = trimmed scalar - crypto_eddsa_scalarbase(public_key, a); // public key = [trimmed scalar]B - COPY(secret_key + 32, public_key, 32); // secret key includes public half - WIPE_BUFFER(a); -} - -static void hash_reduce(u8 h[32], - const u8 *a, size_t a_size, - const u8 *b, size_t b_size, - const u8 *c, size_t c_size, - const u8 *d, size_t d_size) -{ - u8 hash[64]; - crypto_sha512_ctx ctx; - crypto_sha512_init (&ctx); - crypto_sha512_update(&ctx, a, a_size); - crypto_sha512_update(&ctx, b, b_size); - crypto_sha512_update(&ctx, c, c_size); - crypto_sha512_update(&ctx, d, d_size); - crypto_sha512_final (&ctx, hash); - crypto_eddsa_reduce(h, hash); -} - -static void ed25519_dom_sign(u8 signature [64], const u8 secret_key[32], - const u8 *dom, size_t dom_size, - const u8 *message, size_t message_size) -{ - u8 a[64]; // secret scalar and prefix - u8 r[32]; // secret deterministic "random" nonce - u8 h[32]; // publically verifiable hash of the message (not wiped) - u8 R[32]; // first half of the signature (allows overlapping inputs) - const u8 *pk = secret_key + 32; - - crypto_sha512(a, secret_key, 32); - crypto_eddsa_trim_scalar(a, a); - hash_reduce(r, dom, dom_size, a + 32, 32, message, message_size, 0, 0); - crypto_eddsa_scalarbase(R, r); - hash_reduce(h, dom, dom_size, R, 32, pk, 32, message, message_size); - COPY(signature, R, 32); - crypto_eddsa_mul_add(signature + 32, h, a, r); - - WIPE_BUFFER(a); - WIPE_BUFFER(r); -} - -void crypto_ed25519_sign(u8 signature [64], const u8 secret_key[64], - const u8 *message, size_t message_size) -{ - ed25519_dom_sign(signature, secret_key, 0, 0, message, message_size); -} - -int crypto_ed25519_check(const u8 signature[64], const u8 public_key[32], - const u8 *msg, size_t msg_size) -{ - u8 h_ram[32]; - hash_reduce(h_ram, signature, 32, public_key, 32, msg, msg_size, 0, 0); - return crypto_eddsa_check_equation(signature, public_key, h_ram); -} - -static const u8 domain[34] = "SigEd25519 no Ed25519 collisions\1"; - -void crypto_ed25519_ph_sign(uint8_t signature[64], const uint8_t secret_key[64], - const uint8_t message_hash[64]) -{ - ed25519_dom_sign(signature, secret_key, domain, sizeof(domain), - message_hash, 64); -} - -int crypto_ed25519_ph_check(const uint8_t sig[64], const uint8_t pk[32], - const uint8_t msg_hash[64]) -{ - u8 h_ram[32]; - hash_reduce(h_ram, domain, sizeof(domain), sig, 32, pk, 32, msg_hash, 64); - return crypto_eddsa_check_equation(sig, pk, h_ram); -} - - -#ifdef MONOCYPHER_CPP_NAMESPACE -} -#endif diff --git a/monocypher-ed25519.h b/monocypher-ed25519.h deleted file mode 100644 index 1e6d705..0000000 --- a/monocypher-ed25519.h +++ /dev/null @@ -1,140 +0,0 @@ -// Monocypher version 4.0.2 -// -// This file is dual-licensed. Choose whichever licence you want from -// the two licences listed below. -// -// The first licence is a regular 2-clause BSD licence. The second licence -// is the CC-0 from Creative Commons. It is intended to release Monocypher -// to the public domain. The BSD licence serves as a fallback option. -// -// SPDX-License-Identifier: BSD-2-Clause OR CC0-1.0 -// -// ------------------------------------------------------------------------ -// -// Copyright (c) 2017-2019, Loup Vaillant -// All rights reserved. -// -// -// Redistribution and use in source and binary forms, with or without -// modification, are permitted provided that the following conditions are -// met: -// -// 1. Redistributions of source code must retain the above copyright -// notice, this list of conditions and the following disclaimer. -// -// 2. Redistributions in binary form must reproduce the above copyright -// notice, this list of conditions and the following disclaimer in the -// documentation and/or other materials provided with the -// distribution. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -// -// ------------------------------------------------------------------------ -// -// Written in 2017-2019 by Loup Vaillant -// -// To the extent possible under law, the author(s) have dedicated all copyright -// and related neighboring rights to this software to the public domain -// worldwide. This software is distributed without any warranty. -// -// You should have received a copy of the CC0 Public Domain Dedication along -// with this software. If not, see -// - -#ifndef ED25519_H -#define ED25519_H - -#include "monocypher.h" - -#ifdef MONOCYPHER_CPP_NAMESPACE -namespace MONOCYPHER_CPP_NAMESPACE { -#elif defined(__cplusplus) -extern "C" { -#endif - -//////////////////////// -/// Type definitions /// -//////////////////////// - -// Do not rely on the size or content on any of those types, -// they may change without notice. -typedef struct { - uint64_t hash[8]; - uint64_t input[16]; - uint64_t input_size[2]; - size_t input_idx; -} crypto_sha512_ctx; - -typedef struct { - uint8_t key[128]; - crypto_sha512_ctx ctx; -} crypto_sha512_hmac_ctx; - - -// SHA 512 -// ------- -void crypto_sha512_init (crypto_sha512_ctx *ctx); -void crypto_sha512_update(crypto_sha512_ctx *ctx, - const uint8_t *message, size_t message_size); -void crypto_sha512_final (crypto_sha512_ctx *ctx, uint8_t hash[64]); -void crypto_sha512(uint8_t hash[64], - const uint8_t *message, size_t message_size); - -// SHA 512 HMAC -// ------------ -void crypto_sha512_hmac_init(crypto_sha512_hmac_ctx *ctx, - const uint8_t *key, size_t key_size); -void crypto_sha512_hmac_update(crypto_sha512_hmac_ctx *ctx, - const uint8_t *message, size_t message_size); -void crypto_sha512_hmac_final(crypto_sha512_hmac_ctx *ctx, uint8_t hmac[64]); -void crypto_sha512_hmac(uint8_t hmac[64], - const uint8_t *key , size_t key_size, - const uint8_t *message, size_t message_size); - -// SHA 512 HKDF -// ------------ -void crypto_sha512_hkdf_expand(uint8_t *okm, size_t okm_size, - const uint8_t *prk, size_t prk_size, - const uint8_t *info, size_t info_size); -void crypto_sha512_hkdf(uint8_t *okm , size_t okm_size, - const uint8_t *ikm , size_t ikm_size, - const uint8_t *salt, size_t salt_size, - const uint8_t *info, size_t info_size); - -// Ed25519 -// ------- -// Signatures (EdDSA with curve25519 + SHA-512) -// -------------------------------------------- -void crypto_ed25519_key_pair(uint8_t secret_key[64], - uint8_t public_key[32], - uint8_t seed[32]); -void crypto_ed25519_sign(uint8_t signature [64], - const uint8_t secret_key[64], - const uint8_t *message, size_t message_size); -int crypto_ed25519_check(const uint8_t signature [64], - const uint8_t public_key[32], - const uint8_t *message, size_t message_size); - -// Pre-hash variants -void crypto_ed25519_ph_sign(uint8_t signature [64], - const uint8_t secret_key [64], - const uint8_t message_hash[64]); -int crypto_ed25519_ph_check(const uint8_t signature [64], - const uint8_t public_key [32], - const uint8_t message_hash[64]); - -#ifdef __cplusplus -} -#endif - -#endif // ED25519_H diff --git a/monocypher.c b/monocypher.c deleted file mode 100644 index d3930fb..0000000 --- a/monocypher.c +++ /dev/null @@ -1,2956 +0,0 @@ -// Monocypher version 4.0.2 -// -// This file is dual-licensed. Choose whichever licence you want from -// the two licences listed below. -// -// The first licence is a regular 2-clause BSD licence. The second licence -// is the CC-0 from Creative Commons. It is intended to release Monocypher -// to the public domain. The BSD licence serves as a fallback option. -// -// SPDX-License-Identifier: BSD-2-Clause OR CC0-1.0 -// -// ------------------------------------------------------------------------ -// -// Copyright (c) 2017-2020, Loup Vaillant -// All rights reserved. -// -// -// Redistribution and use in source and binary forms, with or without -// modification, are permitted provided that the following conditions are -// met: -// -// 1. Redistributions of source code must retain the above copyright -// notice, this list of conditions and the following disclaimer. -// -// 2. Redistributions in binary form must reproduce the above copyright -// notice, this list of conditions and the following disclaimer in the -// documentation and/or other materials provided with the -// distribution. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -// -// ------------------------------------------------------------------------ -// -// Written in 2017-2020 by Loup Vaillant -// -// To the extent possible under law, the author(s) have dedicated all copyright -// and related neighboring rights to this software to the public domain -// worldwide. This software is distributed without any warranty. -// -// You should have received a copy of the CC0 Public Domain Dedication along -// with this software. If not, see -// - -#include "monocypher.h" - -#ifdef MONOCYPHER_CPP_NAMESPACE -namespace MONOCYPHER_CPP_NAMESPACE { -#endif - -///////////////// -/// Utilities /// -///////////////// -#define FOR_T(type, i, start, end) for (type i = (start); i < (end); i++) -#define FOR(i, start, end) FOR_T(size_t, i, start, end) -#define COPY(dst, src, size) FOR(_i_, 0, size) (dst)[_i_] = (src)[_i_] -#define ZERO(buf, size) FOR(_i_, 0, size) (buf)[_i_] = 0 -#define WIPE_CTX(ctx) crypto_wipe(ctx , sizeof(*(ctx))) -#define WIPE_BUFFER(buffer) crypto_wipe(buffer, sizeof(buffer)) -#define MIN(a, b) ((a) <= (b) ? (a) : (b)) -#define MAX(a, b) ((a) >= (b) ? (a) : (b)) - -typedef int8_t i8; -typedef uint8_t u8; -typedef int16_t i16; -typedef uint32_t u32; -typedef int32_t i32; -typedef int64_t i64; -typedef uint64_t u64; - -static const u8 zero[128] = {0}; - -// returns the smallest positive integer y such that -// (x + y) % pow_2 == 0 -// Basically, y is the "gap" missing to align x. -// Only works when pow_2 is a power of 2. -// Note: we use ~x+1 instead of -x to avoid compiler warnings -static size_t gap(size_t x, size_t pow_2) -{ - return (~x + 1) & (pow_2 - 1); -} - -static u32 load24_le(const u8 s[3]) -{ - return - ((u32)s[0] << 0) | - ((u32)s[1] << 8) | - ((u32)s[2] << 16); -} - -static u32 load32_le(const u8 s[4]) -{ - return - ((u32)s[0] << 0) | - ((u32)s[1] << 8) | - ((u32)s[2] << 16) | - ((u32)s[3] << 24); -} - -static u64 load64_le(const u8 s[8]) -{ - return load32_le(s) | ((u64)load32_le(s+4) << 32); -} - -static void store32_le(u8 out[4], u32 in) -{ - out[0] = in & 0xff; - out[1] = (in >> 8) & 0xff; - out[2] = (in >> 16) & 0xff; - out[3] = (in >> 24) & 0xff; -} - -static void store64_le(u8 out[8], u64 in) -{ - store32_le(out , (u32)in ); - store32_le(out + 4, in >> 32); -} - -static void load32_le_buf (u32 *dst, const u8 *src, size_t size) { - FOR(i, 0, size) { dst[i] = load32_le(src + i*4); } -} -static void load64_le_buf (u64 *dst, const u8 *src, size_t size) { - FOR(i, 0, size) { dst[i] = load64_le(src + i*8); } -} -static void store32_le_buf(u8 *dst, const u32 *src, size_t size) { - FOR(i, 0, size) { store32_le(dst + i*4, src[i]); } -} -static void store64_le_buf(u8 *dst, const u64 *src, size_t size) { - FOR(i, 0, size) { store64_le(dst + i*8, src[i]); } -} - -static u64 rotr64(u64 x, u64 n) { return (x >> n) ^ (x << (64 - n)); } -static u32 rotl32(u32 x, u32 n) { return (x << n) ^ (x >> (32 - n)); } - -static int neq0(u64 diff) -{ - // constant time comparison to zero - // return diff != 0 ? -1 : 0 - u64 half = (diff >> 32) | ((u32)diff); - return (1 & ((half - 1) >> 32)) - 1; -} - -static u64 x16(const u8 a[16], const u8 b[16]) -{ - return (load64_le(a + 0) ^ load64_le(b + 0)) - | (load64_le(a + 8) ^ load64_le(b + 8)); -} -static u64 x32(const u8 a[32],const u8 b[32]){return x16(a,b)| x16(a+16, b+16);} -static u64 x64(const u8 a[64],const u8 b[64]){return x32(a,b)| x32(a+32, b+32);} -int crypto_verify16(const u8 a[16], const u8 b[16]){ return neq0(x16(a, b)); } -int crypto_verify32(const u8 a[32], const u8 b[32]){ return neq0(x32(a, b)); } -int crypto_verify64(const u8 a[64], const u8 b[64]){ return neq0(x64(a, b)); } - -void crypto_wipe(void *secret, size_t size) -{ - volatile u8 *v_secret = (u8*)secret; - ZERO(v_secret, size); -} - -///////////////// -/// Chacha 20 /// -///////////////// -#define QUARTERROUND(a, b, c, d) \ - a += b; d = rotl32(d ^ a, 16); \ - c += d; b = rotl32(b ^ c, 12); \ - a += b; d = rotl32(d ^ a, 8); \ - c += d; b = rotl32(b ^ c, 7) - -static void chacha20_rounds(u32 out[16], const u32 in[16]) -{ - // The temporary variables make Chacha20 10% faster. - u32 t0 = in[ 0]; u32 t1 = in[ 1]; u32 t2 = in[ 2]; u32 t3 = in[ 3]; - u32 t4 = in[ 4]; u32 t5 = in[ 5]; u32 t6 = in[ 6]; u32 t7 = in[ 7]; - u32 t8 = in[ 8]; u32 t9 = in[ 9]; u32 t10 = in[10]; u32 t11 = in[11]; - u32 t12 = in[12]; u32 t13 = in[13]; u32 t14 = in[14]; u32 t15 = in[15]; - - FOR (i, 0, 10) { // 20 rounds, 2 rounds per loop. - QUARTERROUND(t0, t4, t8 , t12); // column 0 - QUARTERROUND(t1, t5, t9 , t13); // column 1 - QUARTERROUND(t2, t6, t10, t14); // column 2 - QUARTERROUND(t3, t7, t11, t15); // column 3 - QUARTERROUND(t0, t5, t10, t15); // diagonal 0 - QUARTERROUND(t1, t6, t11, t12); // diagonal 1 - QUARTERROUND(t2, t7, t8 , t13); // diagonal 2 - QUARTERROUND(t3, t4, t9 , t14); // diagonal 3 - } - out[ 0] = t0; out[ 1] = t1; out[ 2] = t2; out[ 3] = t3; - out[ 4] = t4; out[ 5] = t5; out[ 6] = t6; out[ 7] = t7; - out[ 8] = t8; out[ 9] = t9; out[10] = t10; out[11] = t11; - out[12] = t12; out[13] = t13; out[14] = t14; out[15] = t15; -} - -static const u8 *chacha20_constant = (const u8*)"expand 32-byte k"; // 16 bytes - -void crypto_chacha20_h(u8 out[32], const u8 key[32], const u8 in [16]) -{ - u32 block[16]; - load32_le_buf(block , chacha20_constant, 4); - load32_le_buf(block + 4, key , 8); - load32_le_buf(block + 12, in , 4); - - chacha20_rounds(block, block); - - // prevent reversal of the rounds by revealing only half of the buffer. - store32_le_buf(out , block , 4); // constant - store32_le_buf(out+16, block+12, 4); // counter and nonce - WIPE_BUFFER(block); -} - -u64 crypto_chacha20_djb(u8 *cipher_text, const u8 *plain_text, - size_t text_size, const u8 key[32], const u8 nonce[8], - u64 ctr) -{ - u32 input[16]; - load32_le_buf(input , chacha20_constant, 4); - load32_le_buf(input + 4, key , 8); - load32_le_buf(input + 14, nonce , 2); - input[12] = (u32) ctr; - input[13] = (u32)(ctr >> 32); - - // Whole blocks - u32 pool[16]; - size_t nb_blocks = text_size >> 6; - FOR (i, 0, nb_blocks) { - chacha20_rounds(pool, input); - if (plain_text != 0) { - FOR (j, 0, 16) { - u32 p = pool[j] + input[j]; - store32_le(cipher_text, p ^ load32_le(plain_text)); - cipher_text += 4; - plain_text += 4; - } - } else { - FOR (j, 0, 16) { - u32 p = pool[j] + input[j]; - store32_le(cipher_text, p); - cipher_text += 4; - } - } - input[12]++; - if (input[12] == 0) { - input[13]++; - } - } - text_size &= 63; - - // Last (incomplete) block - if (text_size > 0) { - if (plain_text == 0) { - plain_text = zero; - } - chacha20_rounds(pool, input); - u8 tmp[64]; - FOR (i, 0, 16) { - store32_le(tmp + i*4, pool[i] + input[i]); - } - FOR (i, 0, text_size) { - cipher_text[i] = tmp[i] ^ plain_text[i]; - } - WIPE_BUFFER(tmp); - } - ctr = input[12] + ((u64)input[13] << 32) + (text_size > 0); - - WIPE_BUFFER(pool); - WIPE_BUFFER(input); - return ctr; -} - -u32 crypto_chacha20_ietf(u8 *cipher_text, const u8 *plain_text, - size_t text_size, - const u8 key[32], const u8 nonce[12], u32 ctr) -{ - u64 big_ctr = ctr + ((u64)load32_le(nonce) << 32); - return (u32)crypto_chacha20_djb(cipher_text, plain_text, text_size, - key, nonce + 4, big_ctr); -} - -u64 crypto_chacha20_x(u8 *cipher_text, const u8 *plain_text, - size_t text_size, - const u8 key[32], const u8 nonce[24], u64 ctr) -{ - u8 sub_key[32]; - crypto_chacha20_h(sub_key, key, nonce); - ctr = crypto_chacha20_djb(cipher_text, plain_text, text_size, - sub_key, nonce + 16, ctr); - WIPE_BUFFER(sub_key); - return ctr; -} - -///////////////// -/// Poly 1305 /// -///////////////// - -// h = (h + c) * r -// preconditions: -// ctx->h <= 4_ffffffff_ffffffff_ffffffff_ffffffff -// ctx->r <= 0ffffffc_0ffffffc_0ffffffc_0fffffff -// end <= 1 -// Postcondition: -// ctx->h <= 4_ffffffff_ffffffff_ffffffff_ffffffff -static void poly_blocks(crypto_poly1305_ctx *ctx, const u8 *in, - size_t nb_blocks, unsigned end) -{ - // Local all the things! - const u32 r0 = ctx->r[0]; - const u32 r1 = ctx->r[1]; - const u32 r2 = ctx->r[2]; - const u32 r3 = ctx->r[3]; - const u32 rr0 = (r0 >> 2) * 5; // lose 2 bits... - const u32 rr1 = (r1 >> 2) + r1; // rr1 == (r1 >> 2) * 5 - const u32 rr2 = (r2 >> 2) + r2; // rr1 == (r2 >> 2) * 5 - const u32 rr3 = (r3 >> 2) + r3; // rr1 == (r3 >> 2) * 5 - const u32 rr4 = r0 & 3; // ...recover 2 bits - u32 h0 = ctx->h[0]; - u32 h1 = ctx->h[1]; - u32 h2 = ctx->h[2]; - u32 h3 = ctx->h[3]; - u32 h4 = ctx->h[4]; - - FOR (i, 0, nb_blocks) { - // h + c, without carry propagation - const u64 s0 = (u64)h0 + load32_le(in); in += 4; - const u64 s1 = (u64)h1 + load32_le(in); in += 4; - const u64 s2 = (u64)h2 + load32_le(in); in += 4; - const u64 s3 = (u64)h3 + load32_le(in); in += 4; - const u32 s4 = h4 + end; - - // (h + c) * r, without carry propagation - const u64 x0 = s0*r0+ s1*rr3+ s2*rr2+ s3*rr1+ s4*rr0; - const u64 x1 = s0*r1+ s1*r0 + s2*rr3+ s3*rr2+ s4*rr1; - const u64 x2 = s0*r2+ s1*r1 + s2*r0 + s3*rr3+ s4*rr2; - const u64 x3 = s0*r3+ s1*r2 + s2*r1 + s3*r0 + s4*rr3; - const u32 x4 = s4*rr4; - - // partial reduction modulo 2^130 - 5 - const u32 u5 = x4 + (x3 >> 32); // u5 <= 7ffffff5 - const u64 u0 = (u5 >> 2) * 5 + (x0 & 0xffffffff); - const u64 u1 = (u0 >> 32) + (x1 & 0xffffffff) + (x0 >> 32); - const u64 u2 = (u1 >> 32) + (x2 & 0xffffffff) + (x1 >> 32); - const u64 u3 = (u2 >> 32) + (x3 & 0xffffffff) + (x2 >> 32); - const u32 u4 = (u3 >> 32) + (u5 & 3); // u4 <= 4 - - // Update the hash - h0 = u0 & 0xffffffff; - h1 = u1 & 0xffffffff; - h2 = u2 & 0xffffffff; - h3 = u3 & 0xffffffff; - h4 = u4; - } - ctx->h[0] = h0; - ctx->h[1] = h1; - ctx->h[2] = h2; - ctx->h[3] = h3; - ctx->h[4] = h4; -} - -void crypto_poly1305_init(crypto_poly1305_ctx *ctx, const u8 key[32]) -{ - ZERO(ctx->h, 5); // Initial hash is zero - ctx->c_idx = 0; - // load r and pad (r has some of its bits cleared) - load32_le_buf(ctx->r , key , 4); - load32_le_buf(ctx->pad, key+16, 4); - FOR (i, 0, 1) { ctx->r[i] &= 0x0fffffff; } - FOR (i, 1, 4) { ctx->r[i] &= 0x0ffffffc; } -} - -void crypto_poly1305_update(crypto_poly1305_ctx *ctx, - const u8 *message, size_t message_size) -{ - // Avoid undefined NULL pointer increments with empty messages - if (message_size == 0) { - return; - } - - // Align ourselves with block boundaries - size_t aligned = MIN(gap(ctx->c_idx, 16), message_size); - FOR (i, 0, aligned) { - ctx->c[ctx->c_idx] = *message; - ctx->c_idx++; - message++; - message_size--; - } - - // If block is complete, process it - if (ctx->c_idx == 16) { - poly_blocks(ctx, ctx->c, 1, 1); - ctx->c_idx = 0; - } - - // Process the message block by block - size_t nb_blocks = message_size >> 4; - poly_blocks(ctx, message, nb_blocks, 1); - message += nb_blocks << 4; - message_size &= 15; - - // remaining bytes (we never complete a block here) - FOR (i, 0, message_size) { - ctx->c[ctx->c_idx] = message[i]; - ctx->c_idx++; - } -} - -void crypto_poly1305_final(crypto_poly1305_ctx *ctx, u8 mac[16]) -{ - // Process the last block (if any) - // We move the final 1 according to remaining input length - // (this will add less than 2^130 to the last input block) - if (ctx->c_idx != 0) { - ZERO(ctx->c + ctx->c_idx, 16 - ctx->c_idx); - ctx->c[ctx->c_idx] = 1; - poly_blocks(ctx, ctx->c, 1, 0); - } - - // check if we should subtract 2^130-5 by performing the - // corresponding carry propagation. - u64 c = 5; - FOR (i, 0, 4) { - c += ctx->h[i]; - c >>= 32; - } - c += ctx->h[4]; - c = (c >> 2) * 5; // shift the carry back to the beginning - // c now indicates how many times we should subtract 2^130-5 (0 or 1) - FOR (i, 0, 4) { - c += (u64)ctx->h[i] + ctx->pad[i]; - store32_le(mac + i*4, (u32)c); - c = c >> 32; - } - WIPE_CTX(ctx); -} - -void crypto_poly1305(u8 mac[16], const u8 *message, - size_t message_size, const u8 key[32]) -{ - crypto_poly1305_ctx ctx; - crypto_poly1305_init (&ctx, key); - crypto_poly1305_update(&ctx, message, message_size); - crypto_poly1305_final (&ctx, mac); -} - -//////////////// -/// BLAKE2 b /// -//////////////// -static const u64 iv[8] = { - 0x6a09e667f3bcc908, 0xbb67ae8584caa73b, - 0x3c6ef372fe94f82b, 0xa54ff53a5f1d36f1, - 0x510e527fade682d1, 0x9b05688c2b3e6c1f, - 0x1f83d9abfb41bd6b, 0x5be0cd19137e2179, -}; - -static void blake2b_compress(crypto_blake2b_ctx *ctx, int is_last_block) -{ - static const u8 sigma[12][16] = { - { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }, - { 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 }, - { 11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 }, - { 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 }, - { 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 }, - { 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 }, - { 12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 }, - { 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 }, - { 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 }, - { 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0 }, - { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }, - { 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 }, - }; - - // increment input offset - u64 *x = ctx->input_offset; - size_t y = ctx->input_idx; - x[0] += y; - if (x[0] < y) { - x[1]++; - } - - // init work vector - u64 v0 = ctx->hash[0]; u64 v8 = iv[0]; - u64 v1 = ctx->hash[1]; u64 v9 = iv[1]; - u64 v2 = ctx->hash[2]; u64 v10 = iv[2]; - u64 v3 = ctx->hash[3]; u64 v11 = iv[3]; - u64 v4 = ctx->hash[4]; u64 v12 = iv[4] ^ ctx->input_offset[0]; - u64 v5 = ctx->hash[5]; u64 v13 = iv[5] ^ ctx->input_offset[1]; - u64 v6 = ctx->hash[6]; u64 v14 = iv[6] ^ (u64)~(is_last_block - 1); - u64 v7 = ctx->hash[7]; u64 v15 = iv[7]; - - // mangle work vector - u64 *input = ctx->input; -#define BLAKE2_G(a, b, c, d, x, y) \ - a += b + x; d = rotr64(d ^ a, 32); \ - c += d; b = rotr64(b ^ c, 24); \ - a += b + y; d = rotr64(d ^ a, 16); \ - c += d; b = rotr64(b ^ c, 63) -#define BLAKE2_ROUND(i) \ - BLAKE2_G(v0, v4, v8 , v12, input[sigma[i][ 0]], input[sigma[i][ 1]]); \ - BLAKE2_G(v1, v5, v9 , v13, input[sigma[i][ 2]], input[sigma[i][ 3]]); \ - BLAKE2_G(v2, v6, v10, v14, input[sigma[i][ 4]], input[sigma[i][ 5]]); \ - BLAKE2_G(v3, v7, v11, v15, input[sigma[i][ 6]], input[sigma[i][ 7]]); \ - BLAKE2_G(v0, v5, v10, v15, input[sigma[i][ 8]], input[sigma[i][ 9]]); \ - BLAKE2_G(v1, v6, v11, v12, input[sigma[i][10]], input[sigma[i][11]]); \ - BLAKE2_G(v2, v7, v8 , v13, input[sigma[i][12]], input[sigma[i][13]]); \ - BLAKE2_G(v3, v4, v9 , v14, input[sigma[i][14]], input[sigma[i][15]]) - -#ifdef BLAKE2_NO_UNROLLING - FOR (i, 0, 12) { - BLAKE2_ROUND(i); - } -#else - BLAKE2_ROUND(0); BLAKE2_ROUND(1); BLAKE2_ROUND(2); BLAKE2_ROUND(3); - BLAKE2_ROUND(4); BLAKE2_ROUND(5); BLAKE2_ROUND(6); BLAKE2_ROUND(7); - BLAKE2_ROUND(8); BLAKE2_ROUND(9); BLAKE2_ROUND(10); BLAKE2_ROUND(11); -#endif - - // update hash - ctx->hash[0] ^= v0 ^ v8; ctx->hash[1] ^= v1 ^ v9; - ctx->hash[2] ^= v2 ^ v10; ctx->hash[3] ^= v3 ^ v11; - ctx->hash[4] ^= v4 ^ v12; ctx->hash[5] ^= v5 ^ v13; - ctx->hash[6] ^= v6 ^ v14; ctx->hash[7] ^= v7 ^ v15; -} - -void crypto_blake2b_keyed_init(crypto_blake2b_ctx *ctx, size_t hash_size, - const u8 *key, size_t key_size) -{ - // initial hash - COPY(ctx->hash, iv, 8); - ctx->hash[0] ^= 0x01010000 ^ (key_size << 8) ^ hash_size; - - ctx->input_offset[0] = 0; // beginning of the input, no offset - ctx->input_offset[1] = 0; // beginning of the input, no offset - ctx->hash_size = hash_size; - ctx->input_idx = 0; - ZERO(ctx->input, 16); - - // if there is a key, the first block is that key (padded with zeroes) - if (key_size > 0) { - u8 key_block[128] = {0}; - COPY(key_block, key, key_size); - // same as calling crypto_blake2b_update(ctx, key_block , 128) - load64_le_buf(ctx->input, key_block, 16); - ctx->input_idx = 128; - } -} - -void crypto_blake2b_init(crypto_blake2b_ctx *ctx, size_t hash_size) -{ - crypto_blake2b_keyed_init(ctx, hash_size, 0, 0); -} - -void crypto_blake2b_update(crypto_blake2b_ctx *ctx, - const u8 *message, size_t message_size) -{ - // Avoid undefined NULL pointer increments with empty messages - if (message_size == 0) { - return; - } - - // Align with word boundaries - if ((ctx->input_idx & 7) != 0) { - size_t nb_bytes = MIN(gap(ctx->input_idx, 8), message_size); - size_t word = ctx->input_idx >> 3; - size_t byte = ctx->input_idx & 7; - FOR (i, 0, nb_bytes) { - ctx->input[word] |= (u64)message[i] << ((byte + i) << 3); - } - ctx->input_idx += nb_bytes; - message += nb_bytes; - message_size -= nb_bytes; - } - - // Align with block boundaries (faster than byte by byte) - if ((ctx->input_idx & 127) != 0) { - size_t nb_words = MIN(gap(ctx->input_idx, 128), message_size) >> 3; - load64_le_buf(ctx->input + (ctx->input_idx >> 3), message, nb_words); - ctx->input_idx += nb_words << 3; - message += nb_words << 3; - message_size -= nb_words << 3; - } - - // Process block by block - size_t nb_blocks = message_size >> 7; - FOR (i, 0, nb_blocks) { - if (ctx->input_idx == 128) { - blake2b_compress(ctx, 0); - } - load64_le_buf(ctx->input, message, 16); - message += 128; - ctx->input_idx = 128; - } - message_size &= 127; - - if (message_size != 0) { - // Compress block & flush input buffer as needed - if (ctx->input_idx == 128) { - blake2b_compress(ctx, 0); - ctx->input_idx = 0; - } - if (ctx->input_idx == 0) { - ZERO(ctx->input, 16); - } - // Fill remaining words (faster than byte by byte) - size_t nb_words = message_size >> 3; - load64_le_buf(ctx->input, message, nb_words); - ctx->input_idx += nb_words << 3; - message += nb_words << 3; - message_size -= nb_words << 3; - - // Fill remaining bytes - FOR (i, 0, message_size) { - size_t word = ctx->input_idx >> 3; - size_t byte = ctx->input_idx & 7; - ctx->input[word] |= (u64)message[i] << (byte << 3); - ctx->input_idx++; - } - } -} - -void crypto_blake2b_final(crypto_blake2b_ctx *ctx, u8 *hash) -{ - blake2b_compress(ctx, 1); // compress the last block - size_t hash_size = MIN(ctx->hash_size, 64); - size_t nb_words = hash_size >> 3; - store64_le_buf(hash, ctx->hash, nb_words); - FOR (i, nb_words << 3, hash_size) { - hash[i] = (ctx->hash[i >> 3] >> (8 * (i & 7))) & 0xff; - } - WIPE_CTX(ctx); -} - -void crypto_blake2b_keyed(u8 *hash, size_t hash_size, - const u8 *key, size_t key_size, - const u8 *message, size_t message_size) -{ - crypto_blake2b_ctx ctx; - crypto_blake2b_keyed_init(&ctx, hash_size, key, key_size); - crypto_blake2b_update (&ctx, message, message_size); - crypto_blake2b_final (&ctx, hash); -} - -void crypto_blake2b(u8 *hash, size_t hash_size, const u8 *msg, size_t msg_size) -{ - crypto_blake2b_keyed(hash, hash_size, 0, 0, msg, msg_size); -} - -////////////// -/// Argon2 /// -////////////// -// references to R, Z, Q etc. come from the spec - -// Argon2 operates on 1024 byte blocks. -typedef struct { u64 a[128]; } blk; - -// updates a BLAKE2 hash with a 32 bit word, little endian. -static void blake_update_32(crypto_blake2b_ctx *ctx, u32 input) -{ - u8 buf[4]; - store32_le(buf, input); - crypto_blake2b_update(ctx, buf, 4); - WIPE_BUFFER(buf); -} - -static void blake_update_32_buf(crypto_blake2b_ctx *ctx, - const u8 *buf, u32 size) -{ - blake_update_32(ctx, size); - crypto_blake2b_update(ctx, buf, size); -} - - -static void copy_block(blk *o,const blk*in){FOR(i, 0, 128) o->a[i] = in->a[i];} -static void xor_block(blk *o,const blk*in){FOR(i, 0, 128) o->a[i] ^= in->a[i];} - -// Hash with a virtually unlimited digest size. -// Doesn't extract more entropy than the base hash function. -// Mainly used for filling a whole kilobyte block with pseudo-random bytes. -// (One could use a stream cipher with a seed hash as the key, but -// this would introduce another dependency —and point of failure.) -static void extended_hash(u8 *digest, u32 digest_size, - const u8 *input , u32 input_size) -{ - crypto_blake2b_ctx ctx; - crypto_blake2b_init (&ctx, MIN(digest_size, 64)); - blake_update_32 (&ctx, digest_size); - crypto_blake2b_update(&ctx, input, input_size); - crypto_blake2b_final (&ctx, digest); - - if (digest_size > 64) { - // the conversion to u64 avoids integer overflow on - // ludicrously big hash sizes. - u32 r = (u32)(((u64)digest_size + 31) >> 5) - 2; - u32 i = 1; - u32 in = 0; - u32 out = 32; - while (i < r) { - // Input and output overlap. This is intentional - crypto_blake2b(digest + out, 64, digest + in, 64); - i += 1; - in += 32; - out += 32; - } - crypto_blake2b(digest + out, digest_size - (32 * r), digest + in , 64); - } -} - -#define LSB(x) ((u64)(u32)x) -#define G(a, b, c, d) \ - a += b + ((LSB(a) * LSB(b)) << 1); d ^= a; d = rotr64(d, 32); \ - c += d + ((LSB(c) * LSB(d)) << 1); b ^= c; b = rotr64(b, 24); \ - a += b + ((LSB(a) * LSB(b)) << 1); d ^= a; d = rotr64(d, 16); \ - c += d + ((LSB(c) * LSB(d)) << 1); b ^= c; b = rotr64(b, 63) -#define ROUND(v0, v1, v2, v3, v4, v5, v6, v7, \ - v8, v9, v10, v11, v12, v13, v14, v15) \ - G(v0, v4, v8, v12); G(v1, v5, v9, v13); \ - G(v2, v6, v10, v14); G(v3, v7, v11, v15); \ - G(v0, v5, v10, v15); G(v1, v6, v11, v12); \ - G(v2, v7, v8, v13); G(v3, v4, v9, v14) - -// Core of the compression function G. Computes Z from R in place. -static void g_rounds(blk *b) -{ - // column rounds (work_block = Q) - for (int i = 0; i < 128; i += 16) { - ROUND(b->a[i ], b->a[i+ 1], b->a[i+ 2], b->a[i+ 3], - b->a[i+ 4], b->a[i+ 5], b->a[i+ 6], b->a[i+ 7], - b->a[i+ 8], b->a[i+ 9], b->a[i+10], b->a[i+11], - b->a[i+12], b->a[i+13], b->a[i+14], b->a[i+15]); - } - // row rounds (b = Z) - for (int i = 0; i < 16; i += 2) { - ROUND(b->a[i ], b->a[i+ 1], b->a[i+ 16], b->a[i+ 17], - b->a[i+32], b->a[i+33], b->a[i+ 48], b->a[i+ 49], - b->a[i+64], b->a[i+65], b->a[i+ 80], b->a[i+ 81], - b->a[i+96], b->a[i+97], b->a[i+112], b->a[i+113]); - } -} - -const crypto_argon2_extras crypto_argon2_no_extras = { 0, 0, 0, 0 }; - -void crypto_argon2(u8 *hash, u32 hash_size, void *work_area, - crypto_argon2_config config, - crypto_argon2_inputs inputs, - crypto_argon2_extras extras) -{ - const u32 segment_size = config.nb_blocks / config.nb_lanes / 4; - const u32 lane_size = segment_size * 4; - const u32 nb_blocks = lane_size * config.nb_lanes; // rounding down - - // work area seen as blocks (must be suitably aligned) - blk *blocks = (blk*)work_area; - { - u8 initial_hash[72]; // 64 bytes plus 2 words for future hashes - crypto_blake2b_ctx ctx; - crypto_blake2b_init (&ctx, 64); - blake_update_32 (&ctx, config.nb_lanes ); // p: number of "threads" - blake_update_32 (&ctx, hash_size); - blake_update_32 (&ctx, config.nb_blocks); - blake_update_32 (&ctx, config.nb_passes); - blake_update_32 (&ctx, 0x13); // v: version number - blake_update_32 (&ctx, config.algorithm); // y: Argon2i, Argon2d... - blake_update_32_buf (&ctx, inputs.pass, inputs.pass_size); - blake_update_32_buf (&ctx, inputs.salt, inputs.salt_size); - blake_update_32_buf (&ctx, extras.key, extras.key_size); - blake_update_32_buf (&ctx, extras.ad, extras.ad_size); - crypto_blake2b_final(&ctx, initial_hash); // fill 64 first bytes only - - // fill first 2 blocks of each lane - u8 hash_area[1024]; - FOR_T(u32, l, 0, config.nb_lanes) { - FOR_T(u32, i, 0, 2) { - store32_le(initial_hash + 64, i); // first additional word - store32_le(initial_hash + 68, l); // second additional word - extended_hash(hash_area, 1024, initial_hash, 72); - load64_le_buf(blocks[l * lane_size + i].a, hash_area, 128); - } - } - - WIPE_BUFFER(initial_hash); - WIPE_BUFFER(hash_area); - } - - // Argon2i and Argon2id start with constant time indexing - int constant_time = config.algorithm != CRYPTO_ARGON2_D; - - // Fill (and re-fill) the rest of the blocks - // - // Note: even though each segment within the same slice can be - // computed in parallel, (one thread per lane), we are computing - // them sequentially, because Monocypher doesn't support threads. - // - // Yet optimal performance (and therefore security) requires one - // thread per lane. The only reason Monocypher supports multiple - // lanes is compatibility. - blk tmp; - FOR_T(u32, pass, 0, config.nb_passes) { - FOR_T(u32, slice, 0, 4) { - // On the first slice of the first pass, - // blocks 0 and 1 are already filled, hence pass_offset. - u32 pass_offset = pass == 0 && slice == 0 ? 2 : 0; - u32 slice_offset = slice * segment_size; - - // Argon2id switches back to non-constant time indexing - // after the first two slices of the first pass - if (slice == 2 && config.algorithm == CRYPTO_ARGON2_ID) { - constant_time = 0; - } - - // Each iteration of the following loop may be performed in - // a separate thread. All segments must be fully completed - // before we start filling the next slice. - FOR_T(u32, segment, 0, config.nb_lanes) { - blk index_block; - u32 index_ctr = 1; - FOR_T (u32, block, pass_offset, segment_size) { - // Current and previous blocks - u32 lane_offset = segment * lane_size; - blk *segment_start = blocks + lane_offset + slice_offset; - blk *current = segment_start + block; - blk *previous = - block == 0 && slice_offset == 0 - ? segment_start + lane_size - 1 - : segment_start + block - 1; - - u64 index_seed; - if (constant_time) { - if (block == pass_offset || (block % 128) == 0) { - // Fill or refresh deterministic indices block - - // seed the beginning of the block... - ZERO(index_block.a, 128); - index_block.a[0] = pass; - index_block.a[1] = segment; - index_block.a[2] = slice; - index_block.a[3] = nb_blocks; - index_block.a[4] = config.nb_passes; - index_block.a[5] = config.algorithm; - index_block.a[6] = index_ctr; - index_ctr++; - - // ... then shuffle it - copy_block(&tmp, &index_block); - g_rounds (&index_block); - xor_block (&index_block, &tmp); - copy_block(&tmp, &index_block); - g_rounds (&index_block); - xor_block (&index_block, &tmp); - } - index_seed = index_block.a[block % 128]; - } else { - index_seed = previous->a[0]; - } - - // Establish the reference set. *Approximately* comprises: - // - The last 3 slices (if they exist yet) - // - The already constructed blocks in the current segment - u32 next_slice = ((slice + 1) % 4) * segment_size; - u32 window_start = pass == 0 ? 0 : next_slice; - u32 nb_segments = pass == 0 ? slice : 3; - u64 lane = - pass == 0 && slice == 0 - ? segment - : (index_seed >> 32) % config.nb_lanes; - u32 window_size = - nb_segments * segment_size + - (lane == segment ? block-1 : - block == 0 ? (u32)-1 : 0); - - // Find reference block - u64 j1 = index_seed & 0xffffffff; // block selector - u64 x = (j1 * j1) >> 32; - u64 y = (window_size * x) >> 32; - u64 z = (window_size - 1) - y; - u64 ref = (window_start + z) % lane_size; - u32 index = lane * lane_size + (u32)ref; - blk *reference = blocks + index; - - // Shuffle the previous & reference block - // into the current block - copy_block(&tmp, previous); - xor_block (&tmp, reference); - if (pass == 0) { copy_block(current, &tmp); } - else { xor_block (current, &tmp); } - g_rounds (&tmp); - xor_block (current, &tmp); - } - } - } - } - - // Wipe temporary block - volatile u64* p = tmp.a; - ZERO(p, 128); - - // XOR last blocks of each lane - blk *last_block = blocks + lane_size - 1; - FOR_T (u32, lane, 1, config.nb_lanes) { - blk *next_block = last_block + lane_size; - xor_block(next_block, last_block); - last_block = next_block; - } - - // Serialize last block - u8 final_block[1024]; - store64_le_buf(final_block, last_block->a, 128); - - // Wipe work area - p = (u64*)work_area; - ZERO(p, 128 * nb_blocks); - - // Hash the very last block with H' into the output hash - extended_hash(hash, hash_size, final_block, 1024); - WIPE_BUFFER(final_block); -} - -//////////////////////////////////// -/// Arithmetic modulo 2^255 - 19 /// -//////////////////////////////////// -// Originally taken from SUPERCOP's ref10 implementation. -// A bit bigger than TweetNaCl, over 4 times faster. - -// field element -typedef i32 fe[10]; - -// field constants -// -// fe_one : 1 -// sqrtm1 : sqrt(-1) -// d : -121665 / 121666 -// D2 : 2 * -121665 / 121666 -// lop_x, lop_y: low order point in Edwards coordinates -// ufactor : -sqrt(-1) * 2 -// A2 : 486662^2 (A squared) -static const fe fe_one = {1}; -static const fe sqrtm1 = { - -32595792, -7943725, 9377950, 3500415, 12389472, - -272473, -25146209, -2005654, 326686, 11406482, -}; -static const fe d = { - -10913610, 13857413, -15372611, 6949391, 114729, - -8787816, -6275908, -3247719, -18696448, -12055116, -}; -static const fe D2 = { - -21827239, -5839606, -30745221, 13898782, 229458, - 15978800, -12551817, -6495438, 29715968, 9444199, -}; -static const fe lop_x = { - 21352778, 5345713, 4660180, -8347857, 24143090, - 14568123, 30185756, -12247770, -33528939, 8345319, -}; -static const fe lop_y = { - -6952922, -1265500, 6862341, -7057498, -4037696, - -5447722, 31680899, -15325402, -19365852, 1569102, -}; -static const fe ufactor = { - -1917299, 15887451, -18755900, -7000830, -24778944, - 544946, -16816446, 4011309, -653372, 10741468, -}; -static const fe A2 = { - 12721188, 3529, 0, 0, 0, 0, 0, 0, 0, 0, -}; - -static void fe_0(fe h) { ZERO(h , 10); } -static void fe_1(fe h) { h[0] = 1; ZERO(h+1, 9); } - -static void fe_copy(fe h,const fe f ){FOR(i,0,10) h[i] = f[i]; } -static void fe_neg (fe h,const fe f ){FOR(i,0,10) h[i] = -f[i]; } -static void fe_add (fe h,const fe f,const fe g){FOR(i,0,10) h[i] = f[i] + g[i];} -static void fe_sub (fe h,const fe f,const fe g){FOR(i,0,10) h[i] = f[i] - g[i];} - -static void fe_cswap(fe f, fe g, int b) -{ - i32 mask = -b; // -1 = 0xffffffff - FOR (i, 0, 10) { - i32 x = (f[i] ^ g[i]) & mask; - f[i] = f[i] ^ x; - g[i] = g[i] ^ x; - } -} - -static void fe_ccopy(fe f, const fe g, int b) -{ - i32 mask = -b; // -1 = 0xffffffff - FOR (i, 0, 10) { - i32 x = (f[i] ^ g[i]) & mask; - f[i] = f[i] ^ x; - } -} - - -// Signed carry propagation -// ------------------------ -// -// Let t be a number. It can be uniquely decomposed thus: -// -// t = h*2^26 + l -// such that -2^25 <= l < 2^25 -// -// Let c = (t + 2^25) / 2^26 (rounded down) -// c = (h*2^26 + l + 2^25) / 2^26 (rounded down) -// c = h + (l + 2^25) / 2^26 (rounded down) -// c = h (exactly) -// Because 0 <= l + 2^25 < 2^26 -// -// Let u = t - c*2^26 -// u = h*2^26 + l - h*2^26 -// u = l -// Therefore, -2^25 <= u < 2^25 -// -// Additionally, if |t| < x, then |h| < x/2^26 (rounded down) -// -// Notations: -// - In C, 1<<25 means 2^25. -// - In C, x>>25 means floor(x / (2^25)). -// - All of the above applies with 25 & 24 as well as 26 & 25. -// -// -// Note on negative right shifts -// ----------------------------- -// -// In C, x >> n, where x is a negative integer, is implementation -// defined. In practice, all platforms do arithmetic shift, which is -// equivalent to division by 2^26, rounded down. Some compilers, like -// GCC, even guarantee it. -// -// If we ever stumble upon a platform that does not propagate the sign -// bit (we won't), visible failures will show at the slightest test, and -// the signed shifts can be replaced by the following: -// -// typedef struct { i64 x:39; } s25; -// typedef struct { i64 x:38; } s26; -// i64 shift25(i64 x) { s25 s; s.x = ((u64)x)>>25; return s.x; } -// i64 shift26(i64 x) { s26 s; s.x = ((u64)x)>>26; return s.x; } -// -// Current compilers cannot optimise this, causing a 30% drop in -// performance. Fairly expensive for something that never happens. -// -// -// Precondition -// ------------ -// -// |t0| < 2^63 -// |t1|..|t9| < 2^62 -// -// Algorithm -// --------- -// c = t0 + 2^25 / 2^26 -- |c| <= 2^36 -// t0 -= c * 2^26 -- |t0| <= 2^25 -// t1 += c -- |t1| <= 2^63 -// -// c = t4 + 2^25 / 2^26 -- |c| <= 2^36 -// t4 -= c * 2^26 -- |t4| <= 2^25 -// t5 += c -- |t5| <= 2^63 -// -// c = t1 + 2^24 / 2^25 -- |c| <= 2^38 -// t1 -= c * 2^25 -- |t1| <= 2^24 -// t2 += c -- |t2| <= 2^63 -// -// c = t5 + 2^24 / 2^25 -- |c| <= 2^38 -// t5 -= c * 2^25 -- |t5| <= 2^24 -// t6 += c -- |t6| <= 2^63 -// -// c = t2 + 2^25 / 2^26 -- |c| <= 2^37 -// t2 -= c * 2^26 -- |t2| <= 2^25 < 1.1 * 2^25 (final t2) -// t3 += c -- |t3| <= 2^63 -// -// c = t6 + 2^25 / 2^26 -- |c| <= 2^37 -// t6 -= c * 2^26 -- |t6| <= 2^25 < 1.1 * 2^25 (final t6) -// t7 += c -- |t7| <= 2^63 -// -// c = t3 + 2^24 / 2^25 -- |c| <= 2^38 -// t3 -= c * 2^25 -- |t3| <= 2^24 < 1.1 * 2^24 (final t3) -// t4 += c -- |t4| <= 2^25 + 2^38 < 2^39 -// -// c = t7 + 2^24 / 2^25 -- |c| <= 2^38 -// t7 -= c * 2^25 -- |t7| <= 2^24 < 1.1 * 2^24 (final t7) -// t8 += c -- |t8| <= 2^63 -// -// c = t4 + 2^25 / 2^26 -- |c| <= 2^13 -// t4 -= c * 2^26 -- |t4| <= 2^25 < 1.1 * 2^25 (final t4) -// t5 += c -- |t5| <= 2^24 + 2^13 < 1.1 * 2^24 (final t5) -// -// c = t8 + 2^25 / 2^26 -- |c| <= 2^37 -// t8 -= c * 2^26 -- |t8| <= 2^25 < 1.1 * 2^25 (final t8) -// t9 += c -- |t9| <= 2^63 -// -// c = t9 + 2^24 / 2^25 -- |c| <= 2^38 -// t9 -= c * 2^25 -- |t9| <= 2^24 < 1.1 * 2^24 (final t9) -// t0 += c * 19 -- |t0| <= 2^25 + 2^38*19 < 2^44 -// -// c = t0 + 2^25 / 2^26 -- |c| <= 2^18 -// t0 -= c * 2^26 -- |t0| <= 2^25 < 1.1 * 2^25 (final t0) -// t1 += c -- |t1| <= 2^24 + 2^18 < 1.1 * 2^24 (final t1) -// -// Postcondition -// ------------- -// |t0|, |t2|, |t4|, |t6|, |t8| < 1.1 * 2^25 -// |t1|, |t3|, |t5|, |t7|, |t9| < 1.1 * 2^24 -#define FE_CARRY \ - i64 c; \ - c = (t0 + ((i64)1<<25)) >> 26; t0 -= c * ((i64)1 << 26); t1 += c; \ - c = (t4 + ((i64)1<<25)) >> 26; t4 -= c * ((i64)1 << 26); t5 += c; \ - c = (t1 + ((i64)1<<24)) >> 25; t1 -= c * ((i64)1 << 25); t2 += c; \ - c = (t5 + ((i64)1<<24)) >> 25; t5 -= c * ((i64)1 << 25); t6 += c; \ - c = (t2 + ((i64)1<<25)) >> 26; t2 -= c * ((i64)1 << 26); t3 += c; \ - c = (t6 + ((i64)1<<25)) >> 26; t6 -= c * ((i64)1 << 26); t7 += c; \ - c = (t3 + ((i64)1<<24)) >> 25; t3 -= c * ((i64)1 << 25); t4 += c; \ - c = (t7 + ((i64)1<<24)) >> 25; t7 -= c * ((i64)1 << 25); t8 += c; \ - c = (t4 + ((i64)1<<25)) >> 26; t4 -= c * ((i64)1 << 26); t5 += c; \ - c = (t8 + ((i64)1<<25)) >> 26; t8 -= c * ((i64)1 << 26); t9 += c; \ - c = (t9 + ((i64)1<<24)) >> 25; t9 -= c * ((i64)1 << 25); t0 += c * 19; \ - c = (t0 + ((i64)1<<25)) >> 26; t0 -= c * ((i64)1 << 26); t1 += c; \ - h[0]=(i32)t0; h[1]=(i32)t1; h[2]=(i32)t2; h[3]=(i32)t3; h[4]=(i32)t4; \ - h[5]=(i32)t5; h[6]=(i32)t6; h[7]=(i32)t7; h[8]=(i32)t8; h[9]=(i32)t9 - -// Decodes a field element from a byte buffer. -// mask specifies how many bits we ignore. -// Traditionally we ignore 1. It's useful for EdDSA, -// which uses that bit to denote the sign of x. -// Elligator however uses positive representatives, -// which means ignoring 2 bits instead. -static void fe_frombytes_mask(fe h, const u8 s[32], unsigned nb_mask) -{ - u32 mask = 0xffffff >> nb_mask; - i64 t0 = load32_le(s); // t0 < 2^32 - i64 t1 = load24_le(s + 4) << 6; // t1 < 2^30 - i64 t2 = load24_le(s + 7) << 5; // t2 < 2^29 - i64 t3 = load24_le(s + 10) << 3; // t3 < 2^27 - i64 t4 = load24_le(s + 13) << 2; // t4 < 2^26 - i64 t5 = load32_le(s + 16); // t5 < 2^32 - i64 t6 = load24_le(s + 20) << 7; // t6 < 2^31 - i64 t7 = load24_le(s + 23) << 5; // t7 < 2^29 - i64 t8 = load24_le(s + 26) << 4; // t8 < 2^28 - i64 t9 = (load24_le(s + 29) & mask) << 2; // t9 < 2^25 - FE_CARRY; // Carry precondition OK -} - -static void fe_frombytes(fe h, const u8 s[32]) -{ - fe_frombytes_mask(h, s, 1); -} - - -// Precondition -// |h[0]|, |h[2]|, |h[4]|, |h[6]|, |h[8]| < 1.1 * 2^25 -// |h[1]|, |h[3]|, |h[5]|, |h[7]|, |h[9]| < 1.1 * 2^24 -// -// Therefore, |h| < 2^255-19 -// There are two possibilities: -// -// - If h is positive, all we need to do is reduce its individual -// limbs down to their tight positive range. -// - If h is negative, we also need to add 2^255-19 to it. -// Or just remove 19 and chop off any excess bit. -static void fe_tobytes(u8 s[32], const fe h) -{ - i32 t[10]; - COPY(t, h, 10); - i32 q = (19 * t[9] + (((i32) 1) << 24)) >> 25; - // |t9| < 1.1 * 2^24 - // -1.1 * 2^24 < t9 < 1.1 * 2^24 - // -21 * 2^24 < 19 * t9 < 21 * 2^24 - // -2^29 < 19 * t9 + 2^24 < 2^29 - // -2^29 / 2^25 < (19 * t9 + 2^24) / 2^25 < 2^29 / 2^25 - // -16 < (19 * t9 + 2^24) / 2^25 < 16 - FOR (i, 0, 5) { - q += t[2*i ]; q >>= 26; // q = 0 or -1 - q += t[2*i+1]; q >>= 25; // q = 0 or -1 - } - // q = 0 iff h >= 0 - // q = -1 iff h < 0 - // Adding q * 19 to h reduces h to its proper range. - q *= 19; // Shift carry back to the beginning - FOR (i, 0, 5) { - t[i*2 ] += q; q = t[i*2 ] >> 26; t[i*2 ] -= q * ((i32)1 << 26); - t[i*2+1] += q; q = t[i*2+1] >> 25; t[i*2+1] -= q * ((i32)1 << 25); - } - // h is now fully reduced, and q represents the excess bit. - - store32_le(s + 0, ((u32)t[0] >> 0) | ((u32)t[1] << 26)); - store32_le(s + 4, ((u32)t[1] >> 6) | ((u32)t[2] << 19)); - store32_le(s + 8, ((u32)t[2] >> 13) | ((u32)t[3] << 13)); - store32_le(s + 12, ((u32)t[3] >> 19) | ((u32)t[4] << 6)); - store32_le(s + 16, ((u32)t[5] >> 0) | ((u32)t[6] << 25)); - store32_le(s + 20, ((u32)t[6] >> 7) | ((u32)t[7] << 19)); - store32_le(s + 24, ((u32)t[7] >> 13) | ((u32)t[8] << 12)); - store32_le(s + 28, ((u32)t[8] >> 20) | ((u32)t[9] << 6)); - - WIPE_BUFFER(t); -} - -// Precondition -// ------------- -// |f0|, |f2|, |f4|, |f6|, |f8| < 1.65 * 2^26 -// |f1|, |f3|, |f5|, |f7|, |f9| < 1.65 * 2^25 -// -// |g0|, |g2|, |g4|, |g6|, |g8| < 1.65 * 2^26 -// |g1|, |g3|, |g5|, |g7|, |g9| < 1.65 * 2^25 -static void fe_mul_small(fe h, const fe f, i32 g) -{ - i64 t0 = f[0] * (i64) g; i64 t1 = f[1] * (i64) g; - i64 t2 = f[2] * (i64) g; i64 t3 = f[3] * (i64) g; - i64 t4 = f[4] * (i64) g; i64 t5 = f[5] * (i64) g; - i64 t6 = f[6] * (i64) g; i64 t7 = f[7] * (i64) g; - i64 t8 = f[8] * (i64) g; i64 t9 = f[9] * (i64) g; - // |t0|, |t2|, |t4|, |t6|, |t8| < 1.65 * 2^26 * 2^31 < 2^58 - // |t1|, |t3|, |t5|, |t7|, |t9| < 1.65 * 2^25 * 2^31 < 2^57 - - FE_CARRY; // Carry precondition OK -} - -// Precondition -// ------------- -// |f0|, |f2|, |f4|, |f6|, |f8| < 1.65 * 2^26 -// |f1|, |f3|, |f5|, |f7|, |f9| < 1.65 * 2^25 -// -// |g0|, |g2|, |g4|, |g6|, |g8| < 1.65 * 2^26 -// |g1|, |g3|, |g5|, |g7|, |g9| < 1.65 * 2^25 -static void fe_mul(fe h, const fe f, const fe g) -{ - // Everything is unrolled and put in temporary variables. - // We could roll the loop, but that would make curve25519 twice as slow. - i32 f0 = f[0]; i32 f1 = f[1]; i32 f2 = f[2]; i32 f3 = f[3]; i32 f4 = f[4]; - i32 f5 = f[5]; i32 f6 = f[6]; i32 f7 = f[7]; i32 f8 = f[8]; i32 f9 = f[9]; - i32 g0 = g[0]; i32 g1 = g[1]; i32 g2 = g[2]; i32 g3 = g[3]; i32 g4 = g[4]; - i32 g5 = g[5]; i32 g6 = g[6]; i32 g7 = g[7]; i32 g8 = g[8]; i32 g9 = g[9]; - i32 F1 = f1*2; i32 F3 = f3*2; i32 F5 = f5*2; i32 F7 = f7*2; i32 F9 = f9*2; - i32 G1 = g1*19; i32 G2 = g2*19; i32 G3 = g3*19; - i32 G4 = g4*19; i32 G5 = g5*19; i32 G6 = g6*19; - i32 G7 = g7*19; i32 G8 = g8*19; i32 G9 = g9*19; - // |F1|, |F3|, |F5|, |F7|, |F9| < 1.65 * 2^26 - // |G0|, |G2|, |G4|, |G6|, |G8| < 2^31 - // |G1|, |G3|, |G5|, |G7|, |G9| < 2^30 - - i64 t0 = f0*(i64)g0 + F1*(i64)G9 + f2*(i64)G8 + F3*(i64)G7 + f4*(i64)G6 - + F5*(i64)G5 + f6*(i64)G4 + F7*(i64)G3 + f8*(i64)G2 + F9*(i64)G1; - i64 t1 = f0*(i64)g1 + f1*(i64)g0 + f2*(i64)G9 + f3*(i64)G8 + f4*(i64)G7 - + f5*(i64)G6 + f6*(i64)G5 + f7*(i64)G4 + f8*(i64)G3 + f9*(i64)G2; - i64 t2 = f0*(i64)g2 + F1*(i64)g1 + f2*(i64)g0 + F3*(i64)G9 + f4*(i64)G8 - + F5*(i64)G7 + f6*(i64)G6 + F7*(i64)G5 + f8*(i64)G4 + F9*(i64)G3; - i64 t3 = f0*(i64)g3 + f1*(i64)g2 + f2*(i64)g1 + f3*(i64)g0 + f4*(i64)G9 - + f5*(i64)G8 + f6*(i64)G7 + f7*(i64)G6 + f8*(i64)G5 + f9*(i64)G4; - i64 t4 = f0*(i64)g4 + F1*(i64)g3 + f2*(i64)g2 + F3*(i64)g1 + f4*(i64)g0 - + F5*(i64)G9 + f6*(i64)G8 + F7*(i64)G7 + f8*(i64)G6 + F9*(i64)G5; - i64 t5 = f0*(i64)g5 + f1*(i64)g4 + f2*(i64)g3 + f3*(i64)g2 + f4*(i64)g1 - + f5*(i64)g0 + f6*(i64)G9 + f7*(i64)G8 + f8*(i64)G7 + f9*(i64)G6; - i64 t6 = f0*(i64)g6 + F1*(i64)g5 + f2*(i64)g4 + F3*(i64)g3 + f4*(i64)g2 - + F5*(i64)g1 + f6*(i64)g0 + F7*(i64)G9 + f8*(i64)G8 + F9*(i64)G7; - i64 t7 = f0*(i64)g7 + f1*(i64)g6 + f2*(i64)g5 + f3*(i64)g4 + f4*(i64)g3 - + f5*(i64)g2 + f6*(i64)g1 + f7*(i64)g0 + f8*(i64)G9 + f9*(i64)G8; - i64 t8 = f0*(i64)g8 + F1*(i64)g7 + f2*(i64)g6 + F3*(i64)g5 + f4*(i64)g4 - + F5*(i64)g3 + f6*(i64)g2 + F7*(i64)g1 + f8*(i64)g0 + F9*(i64)G9; - i64 t9 = f0*(i64)g9 + f1*(i64)g8 + f2*(i64)g7 + f3*(i64)g6 + f4*(i64)g5 - + f5*(i64)g4 + f6*(i64)g3 + f7*(i64)g2 + f8*(i64)g1 + f9*(i64)g0; - // t0 < 0.67 * 2^61 - // t1 < 0.41 * 2^61 - // t2 < 0.52 * 2^61 - // t3 < 0.32 * 2^61 - // t4 < 0.38 * 2^61 - // t5 < 0.22 * 2^61 - // t6 < 0.23 * 2^61 - // t7 < 0.13 * 2^61 - // t8 < 0.09 * 2^61 - // t9 < 0.03 * 2^61 - - FE_CARRY; // Everything below 2^62, Carry precondition OK -} - -// Precondition -// ------------- -// |f0|, |f2|, |f4|, |f6|, |f8| < 1.65 * 2^26 -// |f1|, |f3|, |f5|, |f7|, |f9| < 1.65 * 2^25 -// -// Note: we could use fe_mul() for this, but this is significantly faster -static void fe_sq(fe h, const fe f) -{ - i32 f0 = f[0]; i32 f1 = f[1]; i32 f2 = f[2]; i32 f3 = f[3]; i32 f4 = f[4]; - i32 f5 = f[5]; i32 f6 = f[6]; i32 f7 = f[7]; i32 f8 = f[8]; i32 f9 = f[9]; - i32 f0_2 = f0*2; i32 f1_2 = f1*2; i32 f2_2 = f2*2; i32 f3_2 = f3*2; - i32 f4_2 = f4*2; i32 f5_2 = f5*2; i32 f6_2 = f6*2; i32 f7_2 = f7*2; - i32 f5_38 = f5*38; i32 f6_19 = f6*19; i32 f7_38 = f7*38; - i32 f8_19 = f8*19; i32 f9_38 = f9*38; - // |f0_2| , |f2_2| , |f4_2| , |f6_2| , |f8_2| < 1.65 * 2^27 - // |f1_2| , |f3_2| , |f5_2| , |f7_2| , |f9_2| < 1.65 * 2^26 - // |f5_38|, |f6_19|, |f7_38|, |f8_19|, |f9_38| < 2^31 - - i64 t0 = f0 *(i64)f0 + f1_2*(i64)f9_38 + f2_2*(i64)f8_19 - + f3_2*(i64)f7_38 + f4_2*(i64)f6_19 + f5 *(i64)f5_38; - i64 t1 = f0_2*(i64)f1 + f2 *(i64)f9_38 + f3_2*(i64)f8_19 - + f4 *(i64)f7_38 + f5_2*(i64)f6_19; - i64 t2 = f0_2*(i64)f2 + f1_2*(i64)f1 + f3_2*(i64)f9_38 - + f4_2*(i64)f8_19 + f5_2*(i64)f7_38 + f6 *(i64)f6_19; - i64 t3 = f0_2*(i64)f3 + f1_2*(i64)f2 + f4 *(i64)f9_38 - + f5_2*(i64)f8_19 + f6 *(i64)f7_38; - i64 t4 = f0_2*(i64)f4 + f1_2*(i64)f3_2 + f2 *(i64)f2 - + f5_2*(i64)f9_38 + f6_2*(i64)f8_19 + f7 *(i64)f7_38; - i64 t5 = f0_2*(i64)f5 + f1_2*(i64)f4 + f2_2*(i64)f3 - + f6 *(i64)f9_38 + f7_2*(i64)f8_19; - i64 t6 = f0_2*(i64)f6 + f1_2*(i64)f5_2 + f2_2*(i64)f4 - + f3_2*(i64)f3 + f7_2*(i64)f9_38 + f8 *(i64)f8_19; - i64 t7 = f0_2*(i64)f7 + f1_2*(i64)f6 + f2_2*(i64)f5 - + f3_2*(i64)f4 + f8 *(i64)f9_38; - i64 t8 = f0_2*(i64)f8 + f1_2*(i64)f7_2 + f2_2*(i64)f6 - + f3_2*(i64)f5_2 + f4 *(i64)f4 + f9 *(i64)f9_38; - i64 t9 = f0_2*(i64)f9 + f1_2*(i64)f8 + f2_2*(i64)f7 - + f3_2*(i64)f6 + f4 *(i64)f5_2; - // t0 < 0.67 * 2^61 - // t1 < 0.41 * 2^61 - // t2 < 0.52 * 2^61 - // t3 < 0.32 * 2^61 - // t4 < 0.38 * 2^61 - // t5 < 0.22 * 2^61 - // t6 < 0.23 * 2^61 - // t7 < 0.13 * 2^61 - // t8 < 0.09 * 2^61 - // t9 < 0.03 * 2^61 - - FE_CARRY; -} - -// Parity check. Returns 0 if even, 1 if odd -static int fe_isodd(const fe f) -{ - u8 s[32]; - fe_tobytes(s, f); - u8 isodd = s[0] & 1; - WIPE_BUFFER(s); - return isodd; -} - -// Returns 1 if equal, 0 if not equal -static int fe_isequal(const fe f, const fe g) -{ - u8 fs[32]; - u8 gs[32]; - fe_tobytes(fs, f); - fe_tobytes(gs, g); - int isdifferent = crypto_verify32(fs, gs); - WIPE_BUFFER(fs); - WIPE_BUFFER(gs); - return 1 + isdifferent; -} - -// Inverse square root. -// Returns true if x is a square, false otherwise. -// After the call: -// isr = sqrt(1/x) if x is a non-zero square. -// isr = sqrt(sqrt(-1)/x) if x is not a square. -// isr = 0 if x is zero. -// We do not guarantee the sign of the square root. -// -// Notes: -// Let quartic = x^((p-1)/4) -// -// x^((p-1)/2) = chi(x) -// quartic^2 = chi(x) -// quartic = sqrt(chi(x)) -// quartic = 1 or -1 or sqrt(-1) or -sqrt(-1) -// -// Note that x is a square if quartic is 1 or -1 -// There are 4 cases to consider: -// -// if quartic = 1 (x is a square) -// then x^((p-1)/4) = 1 -// x^((p-5)/4) * x = 1 -// x^((p-5)/4) = 1/x -// x^((p-5)/8) = sqrt(1/x) or -sqrt(1/x) -// -// if quartic = -1 (x is a square) -// then x^((p-1)/4) = -1 -// x^((p-5)/4) * x = -1 -// x^((p-5)/4) = -1/x -// x^((p-5)/8) = sqrt(-1) / sqrt(x) -// x^((p-5)/8) * sqrt(-1) = sqrt(-1)^2 / sqrt(x) -// x^((p-5)/8) * sqrt(-1) = -1/sqrt(x) -// x^((p-5)/8) * sqrt(-1) = -sqrt(1/x) or sqrt(1/x) -// -// if quartic = sqrt(-1) (x is not a square) -// then x^((p-1)/4) = sqrt(-1) -// x^((p-5)/4) * x = sqrt(-1) -// x^((p-5)/4) = sqrt(-1)/x -// x^((p-5)/8) = sqrt(sqrt(-1)/x) or -sqrt(sqrt(-1)/x) -// -// Note that the product of two non-squares is always a square: -// For any non-squares a and b, chi(a) = -1 and chi(b) = -1. -// Since chi(x) = x^((p-1)/2), chi(a)*chi(b) = chi(a*b) = 1. -// Therefore a*b is a square. -// -// Since sqrt(-1) and x are both non-squares, their product is a -// square, and we can compute their square root. -// -// if quartic = -sqrt(-1) (x is not a square) -// then x^((p-1)/4) = -sqrt(-1) -// x^((p-5)/4) * x = -sqrt(-1) -// x^((p-5)/4) = -sqrt(-1)/x -// x^((p-5)/8) = sqrt(-sqrt(-1)/x) -// x^((p-5)/8) = sqrt( sqrt(-1)/x) * sqrt(-1) -// x^((p-5)/8) * sqrt(-1) = sqrt( sqrt(-1)/x) * sqrt(-1)^2 -// x^((p-5)/8) * sqrt(-1) = sqrt( sqrt(-1)/x) * -1 -// x^((p-5)/8) * sqrt(-1) = -sqrt(sqrt(-1)/x) or sqrt(sqrt(-1)/x) -static int invsqrt(fe isr, const fe x) -{ - fe t0, t1, t2; - - // t0 = x^((p-5)/8) - // Can be achieved with a simple double & add ladder, - // but it would be slower. - fe_sq(t0, x); - fe_sq(t1,t0); fe_sq(t1, t1); fe_mul(t1, x, t1); - fe_mul(t0, t0, t1); - fe_sq(t0, t0); fe_mul(t0, t1, t0); - fe_sq(t1, t0); FOR (i, 1, 5) { fe_sq(t1, t1); } fe_mul(t0, t1, t0); - fe_sq(t1, t0); FOR (i, 1, 10) { fe_sq(t1, t1); } fe_mul(t1, t1, t0); - fe_sq(t2, t1); FOR (i, 1, 20) { fe_sq(t2, t2); } fe_mul(t1, t2, t1); - fe_sq(t1, t1); FOR (i, 1, 10) { fe_sq(t1, t1); } fe_mul(t0, t1, t0); - fe_sq(t1, t0); FOR (i, 1, 50) { fe_sq(t1, t1); } fe_mul(t1, t1, t0); - fe_sq(t2, t1); FOR (i, 1, 100) { fe_sq(t2, t2); } fe_mul(t1, t2, t1); - fe_sq(t1, t1); FOR (i, 1, 50) { fe_sq(t1, t1); } fe_mul(t0, t1, t0); - fe_sq(t0, t0); FOR (i, 1, 2) { fe_sq(t0, t0); } fe_mul(t0, t0, x); - - // quartic = x^((p-1)/4) - i32 *quartic = t1; - fe_sq (quartic, t0); - fe_mul(quartic, quartic, x); - - i32 *check = t2; - fe_0 (check); int z0 = fe_isequal(x , check); - fe_1 (check); int p1 = fe_isequal(quartic, check); - fe_neg(check, check ); int m1 = fe_isequal(quartic, check); - fe_neg(check, sqrtm1); int ms = fe_isequal(quartic, check); - - // if quartic == -1 or sqrt(-1) - // then isr = x^((p-1)/4) * sqrt(-1) - // else isr = x^((p-1)/4) - fe_mul(isr, t0, sqrtm1); - fe_ccopy(isr, t0, 1 - (m1 | ms)); - - WIPE_BUFFER(t0); - WIPE_BUFFER(t1); - WIPE_BUFFER(t2); - return p1 | m1 | z0; -} - -// Inverse in terms of inverse square root. -// Requires two additional squarings to get rid of the sign. -// -// 1/x = x * (+invsqrt(x^2))^2 -// = x * (-invsqrt(x^2))^2 -// -// A fully optimised exponentiation by p-1 would save 6 field -// multiplications, but it would require more code. -static void fe_invert(fe out, const fe x) -{ - fe tmp; - fe_sq(tmp, x); - invsqrt(tmp, tmp); - fe_sq(tmp, tmp); - fe_mul(out, tmp, x); - WIPE_BUFFER(tmp); -} - -// trim a scalar for scalar multiplication -void crypto_eddsa_trim_scalar(u8 out[32], const u8 in[32]) -{ - COPY(out, in, 32); - out[ 0] &= 248; - out[31] &= 127; - out[31] |= 64; -} - -// get bit from scalar at position i -static int scalar_bit(const u8 s[32], int i) -{ - if (i < 0) { return 0; } // handle -1 for sliding windows - return (s[i>>3] >> (i&7)) & 1; -} - -/////////////// -/// X-25519 /// Taken from SUPERCOP's ref10 implementation. -/////////////// -static void scalarmult(u8 q[32], const u8 scalar[32], const u8 p[32], - int nb_bits) -{ - // computes the scalar product - fe x1; - fe_frombytes(x1, p); - - // computes the actual scalar product (the result is in x2 and z2) - fe x2, z2, x3, z3, t0, t1; - // Montgomery ladder - // In projective coordinates, to avoid divisions: x = X / Z - // We don't care about the y coordinate, it's only 1 bit of information - fe_1(x2); fe_0(z2); // "zero" point - fe_copy(x3, x1); fe_1(z3); // "one" point - int swap = 0; - for (int pos = nb_bits-1; pos >= 0; --pos) { - // constant time conditional swap before ladder step - int b = scalar_bit(scalar, pos); - swap ^= b; // xor trick avoids swapping at the end of the loop - fe_cswap(x2, x3, swap); - fe_cswap(z2, z3, swap); - swap = b; // anticipates one last swap after the loop - - // Montgomery ladder step: replaces (P2, P3) by (P2*2, P2+P3) - // with differential addition - fe_sub(t0, x3, z3); - fe_sub(t1, x2, z2); - fe_add(x2, x2, z2); - fe_add(z2, x3, z3); - fe_mul(z3, t0, x2); - fe_mul(z2, z2, t1); - fe_sq (t0, t1 ); - fe_sq (t1, x2 ); - fe_add(x3, z3, z2); - fe_sub(z2, z3, z2); - fe_mul(x2, t1, t0); - fe_sub(t1, t1, t0); - fe_sq (z2, z2 ); - fe_mul_small(z3, t1, 121666); - fe_sq (x3, x3 ); - fe_add(t0, t0, z3); - fe_mul(z3, x1, z2); - fe_mul(z2, t1, t0); - } - // last swap is necessary to compensate for the xor trick - // Note: after this swap, P3 == P2 + P1. - fe_cswap(x2, x3, swap); - fe_cswap(z2, z3, swap); - - // normalises the coordinates: x == X / Z - fe_invert(z2, z2); - fe_mul(x2, x2, z2); - fe_tobytes(q, x2); - - WIPE_BUFFER(x1); - WIPE_BUFFER(x2); WIPE_BUFFER(z2); WIPE_BUFFER(t0); - WIPE_BUFFER(x3); WIPE_BUFFER(z3); WIPE_BUFFER(t1); -} - -void crypto_x25519(u8 raw_shared_secret[32], - const u8 your_secret_key [32], - const u8 their_public_key [32]) -{ - // restrict the possible scalar values - u8 e[32]; - crypto_eddsa_trim_scalar(e, your_secret_key); - scalarmult(raw_shared_secret, e, their_public_key, 255); - WIPE_BUFFER(e); -} - -void crypto_x25519_public_key(u8 public_key[32], - const u8 secret_key[32]) -{ - static const u8 base_point[32] = {9}; - crypto_x25519(public_key, secret_key, base_point); -} - -/////////////////////////// -/// Arithmetic modulo L /// -/////////////////////////// -static const u32 L[8] = { - 0x5cf5d3ed, 0x5812631a, 0xa2f79cd6, 0x14def9de, - 0x00000000, 0x00000000, 0x00000000, 0x10000000, -}; - -// p = a*b + p -static void multiply(u32 p[16], const u32 a[8], const u32 b[8]) -{ - FOR (i, 0, 8) { - u64 carry = 0; - FOR (j, 0, 8) { - carry += p[i+j] + (u64)a[i] * b[j]; - p[i+j] = (u32)carry; - carry >>= 32; - } - p[i+8] = (u32)carry; - } -} - -static int is_above_l(const u32 x[8]) -{ - // We work with L directly, in a 2's complement encoding - // (-L == ~L + 1) - u64 carry = 1; - FOR (i, 0, 8) { - carry += (u64)x[i] + (~L[i] & 0xffffffff); - carry >>= 32; - } - return (int)carry; // carry is either 0 or 1 -} - -// Final reduction modulo L, by conditionally removing L. -// if x < l , then r = x -// if l <= x 2*l, then r = x-l -// otherwise the result will be wrong -static void remove_l(u32 r[8], const u32 x[8]) -{ - u64 carry = (u64)is_above_l(x); - u32 mask = ~(u32)carry + 1; // carry == 0 or 1 - FOR (i, 0, 8) { - carry += (u64)x[i] + (~L[i] & mask); - r[i] = (u32)carry; - carry >>= 32; - } -} - -// Full reduction modulo L (Barrett reduction) -static void mod_l(u8 reduced[32], const u32 x[16]) -{ - static const u32 r[9] = { - 0x0a2c131b,0xed9ce5a3,0x086329a7,0x2106215d, - 0xffffffeb,0xffffffff,0xffffffff,0xffffffff,0xf, - }; - // xr = x * r - u32 xr[25] = {0}; - FOR (i, 0, 9) { - u64 carry = 0; - FOR (j, 0, 16) { - carry += xr[i+j] + (u64)r[i] * x[j]; - xr[i+j] = (u32)carry; - carry >>= 32; - } - xr[i+16] = (u32)carry; - } - // xr = floor(xr / 2^512) * L - // Since the result is guaranteed to be below 2*L, - // it is enough to only compute the first 256 bits. - // The division is performed by saying xr[i+16]. (16 * 32 = 512) - ZERO(xr, 8); - FOR (i, 0, 8) { - u64 carry = 0; - FOR (j, 0, 8-i) { - carry += xr[i+j] + (u64)xr[i+16] * L[j]; - xr[i+j] = (u32)carry; - carry >>= 32; - } - } - // xr = x - xr - u64 carry = 1; - FOR (i, 0, 8) { - carry += (u64)x[i] + (~xr[i] & 0xffffffff); - xr[i] = (u32)carry; - carry >>= 32; - } - // Final reduction modulo L (conditional subtraction) - remove_l(xr, xr); - store32_le_buf(reduced, xr, 8); - - WIPE_BUFFER(xr); -} - -void crypto_eddsa_reduce(u8 reduced[32], const u8 expanded[64]) -{ - u32 x[16]; - load32_le_buf(x, expanded, 16); - mod_l(reduced, x); - WIPE_BUFFER(x); -} - -// r = (a * b) + c -void crypto_eddsa_mul_add(u8 r[32], - const u8 a[32], const u8 b[32], const u8 c[32]) -{ - u32 A[8]; load32_le_buf(A, a, 8); - u32 B[8]; load32_le_buf(B, b, 8); - u32 p[16]; load32_le_buf(p, c, 8); ZERO(p + 8, 8); - multiply(p, A, B); - mod_l(r, p); - WIPE_BUFFER(p); - WIPE_BUFFER(A); - WIPE_BUFFER(B); -} - -/////////////// -/// Ed25519 /// -/////////////// - -// Point (group element, ge) in a twisted Edwards curve, -// in extended projective coordinates. -// ge : x = X/Z, y = Y/Z, T = XY/Z -// ge_cached : Yp = X+Y, Ym = X-Y, T2 = T*D2 -// ge_precomp: Z = 1 -typedef struct { fe X; fe Y; fe Z; fe T; } ge; -typedef struct { fe Yp; fe Ym; fe Z; fe T2; } ge_cached; -typedef struct { fe Yp; fe Ym; fe T2; } ge_precomp; - -static void ge_zero(ge *p) -{ - fe_0(p->X); - fe_1(p->Y); - fe_1(p->Z); - fe_0(p->T); -} - -static void ge_tobytes(u8 s[32], const ge *h) -{ - fe recip, x, y; - fe_invert(recip, h->Z); - fe_mul(x, h->X, recip); - fe_mul(y, h->Y, recip); - fe_tobytes(s, y); - s[31] ^= fe_isodd(x) << 7; - - WIPE_BUFFER(recip); - WIPE_BUFFER(x); - WIPE_BUFFER(y); -} - -// h = -s, where s is a point encoded in 32 bytes -// -// Variable time! Inputs must not be secret! -// => Use only to *check* signatures. -// -// From the specifications: -// The encoding of s contains y and the sign of x -// x = sqrt((y^2 - 1) / (d*y^2 + 1)) -// In extended coordinates: -// X = x, Y = y, Z = 1, T = x*y -// -// Note that num * den is a square iff num / den is a square -// If num * den is not a square, the point was not on the curve. -// From the above: -// Let num = y^2 - 1 -// Let den = d*y^2 + 1 -// x = sqrt((y^2 - 1) / (d*y^2 + 1)) -// x = sqrt(num / den) -// x = sqrt(num^2 / (num * den)) -// x = num * sqrt(1 / (num * den)) -// -// Therefore, we can just compute: -// num = y^2 - 1 -// den = d*y^2 + 1 -// isr = invsqrt(num * den) // abort if not square -// x = num * isr -// Finally, negate x if its sign is not as specified. -static int ge_frombytes_neg_vartime(ge *h, const u8 s[32]) -{ - fe_frombytes(h->Y, s); - fe_1(h->Z); - fe_sq (h->T, h->Y); // t = y^2 - fe_mul(h->X, h->T, d ); // x = d*y^2 - fe_sub(h->T, h->T, h->Z); // t = y^2 - 1 - fe_add(h->X, h->X, h->Z); // x = d*y^2 + 1 - fe_mul(h->X, h->T, h->X); // x = (y^2 - 1) * (d*y^2 + 1) - int is_square = invsqrt(h->X, h->X); - if (!is_square) { - return -1; // Not on the curve, abort - } - fe_mul(h->X, h->T, h->X); // x = sqrt((y^2 - 1) / (d*y^2 + 1)) - if (fe_isodd(h->X) == (s[31] >> 7)) { - fe_neg(h->X, h->X); - } - fe_mul(h->T, h->X, h->Y); - return 0; -} - -static void ge_cache(ge_cached *c, const ge *p) -{ - fe_add (c->Yp, p->Y, p->X); - fe_sub (c->Ym, p->Y, p->X); - fe_copy(c->Z , p->Z ); - fe_mul (c->T2, p->T, D2 ); -} - -// Internal buffers are not wiped! Inputs must not be secret! -// => Use only to *check* signatures. -static void ge_add(ge *s, const ge *p, const ge_cached *q) -{ - fe a, b; - fe_add(a , p->Y, p->X ); - fe_sub(b , p->Y, p->X ); - fe_mul(a , a , q->Yp); - fe_mul(b , b , q->Ym); - fe_add(s->Y, a , b ); - fe_sub(s->X, a , b ); - - fe_add(s->Z, p->Z, p->Z ); - fe_mul(s->Z, s->Z, q->Z ); - fe_mul(s->T, p->T, q->T2); - fe_add(a , s->Z, s->T ); - fe_sub(b , s->Z, s->T ); - - fe_mul(s->T, s->X, s->Y); - fe_mul(s->X, s->X, b ); - fe_mul(s->Y, s->Y, a ); - fe_mul(s->Z, a , b ); -} - -// Internal buffers are not wiped! Inputs must not be secret! -// => Use only to *check* signatures. -static void ge_sub(ge *s, const ge *p, const ge_cached *q) -{ - ge_cached neg; - fe_copy(neg.Ym, q->Yp); - fe_copy(neg.Yp, q->Ym); - fe_copy(neg.Z , q->Z ); - fe_neg (neg.T2, q->T2); - ge_add(s, p, &neg); -} - -static void ge_madd(ge *s, const ge *p, const ge_precomp *q, fe a, fe b) -{ - fe_add(a , p->Y, p->X ); - fe_sub(b , p->Y, p->X ); - fe_mul(a , a , q->Yp); - fe_mul(b , b , q->Ym); - fe_add(s->Y, a , b ); - fe_sub(s->X, a , b ); - - fe_add(s->Z, p->Z, p->Z ); - fe_mul(s->T, p->T, q->T2); - fe_add(a , s->Z, s->T ); - fe_sub(b , s->Z, s->T ); - - fe_mul(s->T, s->X, s->Y); - fe_mul(s->X, s->X, b ); - fe_mul(s->Y, s->Y, a ); - fe_mul(s->Z, a , b ); -} - -// Internal buffers are not wiped! Inputs must not be secret! -// => Use only to *check* signatures. -static void ge_msub(ge *s, const ge *p, const ge_precomp *q, fe a, fe b) -{ - ge_precomp neg; - fe_copy(neg.Ym, q->Yp); - fe_copy(neg.Yp, q->Ym); - fe_neg (neg.T2, q->T2); - ge_madd(s, p, &neg, a, b); -} - -static void ge_double(ge *s, const ge *p, ge *q) -{ - fe_sq (q->X, p->X); - fe_sq (q->Y, p->Y); - fe_sq (q->Z, p->Z); // qZ = pZ^2 - fe_mul_small(q->Z, q->Z, 2); // qZ = pZ^2 * 2 - fe_add(q->T, p->X, p->Y); - fe_sq (s->T, q->T); - fe_add(q->T, q->Y, q->X); - fe_sub(q->Y, q->Y, q->X); - fe_sub(q->X, s->T, q->T); - fe_sub(q->Z, q->Z, q->Y); - - fe_mul(s->X, q->X , q->Z); - fe_mul(s->Y, q->T , q->Y); - fe_mul(s->Z, q->Y , q->Z); - fe_mul(s->T, q->X , q->T); -} - -// 5-bit signed window in cached format (Niels coordinates, Z=1) -static const ge_precomp b_window[8] = { - {{25967493,-14356035,29566456,3660896,-12694345, - 4014787,27544626,-11754271,-6079156,2047605,}, - {-12545711,934262,-2722910,3049990,-727428, - 9406986,12720692,5043384,19500929,-15469378,}, - {-8738181,4489570,9688441,-14785194,10184609, - -12363380,29287919,11864899,-24514362,-4438546,},}, - {{15636291,-9688557,24204773,-7912398,616977, - -16685262,27787600,-14772189,28944400,-1550024,}, - {16568933,4717097,-11556148,-1102322,15682896, - -11807043,16354577,-11775962,7689662,11199574,}, - {30464156,-5976125,-11779434,-15670865,23220365, - 15915852,7512774,10017326,-17749093,-9920357,},}, - {{10861363,11473154,27284546,1981175,-30064349, - 12577861,32867885,14515107,-15438304,10819380,}, - {4708026,6336745,20377586,9066809,-11272109, - 6594696,-25653668,12483688,-12668491,5581306,}, - {19563160,16186464,-29386857,4097519,10237984, - -4348115,28542350,13850243,-23678021,-15815942,},}, - {{5153746,9909285,1723747,-2777874,30523605, - 5516873,19480852,5230134,-23952439,-15175766,}, - {-30269007,-3463509,7665486,10083793,28475525, - 1649722,20654025,16520125,30598449,7715701,}, - {28881845,14381568,9657904,3680757,-20181635, - 7843316,-31400660,1370708,29794553,-1409300,},}, - {{-22518993,-6692182,14201702,-8745502,-23510406, - 8844726,18474211,-1361450,-13062696,13821877,}, - {-6455177,-7839871,3374702,-4740862,-27098617, - -10571707,31655028,-7212327,18853322,-14220951,}, - {4566830,-12963868,-28974889,-12240689,-7602672, - -2830569,-8514358,-10431137,2207753,-3209784,},}, - {{-25154831,-4185821,29681144,7868801,-6854661, - -9423865,-12437364,-663000,-31111463,-16132436,}, - {25576264,-2703214,7349804,-11814844,16472782, - 9300885,3844789,15725684,171356,6466918,}, - {23103977,13316479,9739013,-16149481,817875, - -15038942,8965339,-14088058,-30714912,16193877,},}, - {{-33521811,3180713,-2394130,14003687,-16903474, - -16270840,17238398,4729455,-18074513,9256800,}, - {-25182317,-4174131,32336398,5036987,-21236817, - 11360617,22616405,9761698,-19827198,630305,}, - {-13720693,2639453,-24237460,-7406481,9494427, - -5774029,-6554551,-15960994,-2449256,-14291300,},}, - {{-3151181,-5046075,9282714,6866145,-31907062, - -863023,-18940575,15033784,25105118,-7894876,}, - {-24326370,15950226,-31801215,-14592823,-11662737, - -5090925,1573892,-2625887,2198790,-15804619,}, - {-3099351,10324967,-2241613,7453183,-5446979, - -2735503,-13812022,-16236442,-32461234,-12290683,},}, -}; - -// Incremental sliding windows (left to right) -// Based on Roberto Maria Avanzi[2005] -typedef struct { - i16 next_index; // position of the next signed digit - i8 next_digit; // next signed digit (odd number below 2^window_width) - u8 next_check; // point at which we must check for a new window -} slide_ctx; - -static void slide_init(slide_ctx *ctx, const u8 scalar[32]) -{ - // scalar is guaranteed to be below L, either because we checked (s), - // or because we reduced it modulo L (h_ram). L is under 2^253, so - // so bits 253 to 255 are guaranteed to be zero. No need to test them. - // - // Note however that L is very close to 2^252, so bit 252 is almost - // always zero. If we were to start at bit 251, the tests wouldn't - // catch the off-by-one error (constructing one that does would be - // prohibitively expensive). - // - // We should still check bit 252, though. - int i = 252; - while (i > 0 && scalar_bit(scalar, i) == 0) { - i--; - } - ctx->next_check = (u8)(i + 1); - ctx->next_index = -1; - ctx->next_digit = -1; -} - -static int slide_step(slide_ctx *ctx, int width, int i, const u8 scalar[32]) -{ - if (i == ctx->next_check) { - if (scalar_bit(scalar, i) == scalar_bit(scalar, i - 1)) { - ctx->next_check--; - } else { - // compute digit of next window - int w = MIN(width, i + 1); - int v = -(scalar_bit(scalar, i) << (w-1)); - FOR_T (int, j, 0, w-1) { - v += scalar_bit(scalar, i-(w-1)+j) << j; - } - v += scalar_bit(scalar, i-w); - int lsb = v & (~v + 1); // smallest bit of v - int s = // log2(lsb) - (((lsb & 0xAA) != 0) << 0) | - (((lsb & 0xCC) != 0) << 1) | - (((lsb & 0xF0) != 0) << 2); - ctx->next_index = (i16)(i-(w-1)+s); - ctx->next_digit = (i8) (v >> s ); - ctx->next_check -= (u8) w; - } - } - return i == ctx->next_index ? ctx->next_digit: 0; -} - -#define P_W_WIDTH 3 // Affects the size of the stack -#define B_W_WIDTH 5 // Affects the size of the binary -#define P_W_SIZE (1<<(P_W_WIDTH-2)) - -int crypto_eddsa_check_equation(const u8 signature[64], const u8 public_key[32], - const u8 h[32]) -{ - ge minus_A; // -public_key - ge minus_R; // -first_half_of_signature - const u8 *s = signature + 32; - - // Check that A and R are on the curve - // Check that 0 <= S < L (prevents malleability) - // *Allow* non-cannonical encoding for A and R - { - u32 s32[8]; - load32_le_buf(s32, s, 8); - if (ge_frombytes_neg_vartime(&minus_A, public_key) || - ge_frombytes_neg_vartime(&minus_R, signature) || - is_above_l(s32)) { - return -1; - } - } - - // look-up table for minus_A - ge_cached lutA[P_W_SIZE]; - { - ge minus_A2, tmp; - ge_double(&minus_A2, &minus_A, &tmp); - ge_cache(&lutA[0], &minus_A); - FOR (i, 1, P_W_SIZE) { - ge_add(&tmp, &minus_A2, &lutA[i-1]); - ge_cache(&lutA[i], &tmp); - } - } - - // sum = [s]B - [h]A - // Merged double and add ladder, fused with sliding - slide_ctx h_slide; slide_init(&h_slide, h); - slide_ctx s_slide; slide_init(&s_slide, s); - int i = MAX(h_slide.next_check, s_slide.next_check); - ge *sum = &minus_A; // reuse minus_A for the sum - ge_zero(sum); - while (i >= 0) { - ge tmp; - ge_double(sum, sum, &tmp); - int h_digit = slide_step(&h_slide, P_W_WIDTH, i, h); - int s_digit = slide_step(&s_slide, B_W_WIDTH, i, s); - if (h_digit > 0) { ge_add(sum, sum, &lutA[ h_digit / 2]); } - if (h_digit < 0) { ge_sub(sum, sum, &lutA[-h_digit / 2]); } - fe t1, t2; - if (s_digit > 0) { ge_madd(sum, sum, b_window + s_digit/2, t1, t2); } - if (s_digit < 0) { ge_msub(sum, sum, b_window + -s_digit/2, t1, t2); } - i--; - } - - // Compare [8](sum-R) and the zero point - // The multiplication by 8 eliminates any low-order component - // and ensures consistency with batched verification. - ge_cached cached; - u8 check[32]; - static const u8 zero_point[32] = {1}; // Point of order 1 - ge_cache(&cached, &minus_R); - ge_add(sum, sum, &cached); - ge_double(sum, sum, &minus_R); // reuse minus_R as temporary - ge_double(sum, sum, &minus_R); // reuse minus_R as temporary - ge_double(sum, sum, &minus_R); // reuse minus_R as temporary - ge_tobytes(check, sum); - return crypto_verify32(check, zero_point); -} - -// 5-bit signed comb in cached format (Niels coordinates, Z=1) -static const ge_precomp b_comb_low[8] = { - {{-6816601,-2324159,-22559413,124364,18015490, - 8373481,19993724,1979872,-18549925,9085059,}, - {10306321,403248,14839893,9633706,8463310, - -8354981,-14305673,14668847,26301366,2818560,}, - {-22701500,-3210264,-13831292,-2927732,-16326337, - -14016360,12940910,177905,12165515,-2397893,},}, - {{-12282262,-7022066,9920413,-3064358,-32147467, - 2927790,22392436,-14852487,2719975,16402117,}, - {-7236961,-4729776,2685954,-6525055,-24242706, - -15940211,-6238521,14082855,10047669,12228189,}, - {-30495588,-12893761,-11161261,3539405,-11502464, - 16491580,-27286798,-15030530,-7272871,-15934455,},}, - {{17650926,582297,-860412,-187745,-12072900, - -10683391,-20352381,15557840,-31072141,-5019061,}, - {-6283632,-2259834,-4674247,-4598977,-4089240, - 12435688,-31278303,1060251,6256175,10480726,}, - {-13871026,2026300,-21928428,-2741605,-2406664, - -8034988,7355518,15733500,-23379862,7489131,},}, - {{6883359,695140,23196907,9644202,-33430614, - 11354760,-20134606,6388313,-8263585,-8491918,}, - {-7716174,-13605463,-13646110,14757414,-19430591, - -14967316,10359532,-11059670,-21935259,12082603,}, - {-11253345,-15943946,10046784,5414629,24840771, - 8086951,-6694742,9868723,15842692,-16224787,},}, - {{9639399,11810955,-24007778,-9320054,3912937, - -9856959,996125,-8727907,-8919186,-14097242,}, - {7248867,14468564,25228636,-8795035,14346339, - 8224790,6388427,-7181107,6468218,-8720783,}, - {15513115,15439095,7342322,-10157390,18005294, - -7265713,2186239,4884640,10826567,7135781,},}, - {{-14204238,5297536,-5862318,-6004934,28095835, - 4236101,-14203318,1958636,-16816875,3837147,}, - {-5511166,-13176782,-29588215,12339465,15325758, - -15945770,-8813185,11075932,-19608050,-3776283,}, - {11728032,9603156,-4637821,-5304487,-7827751, - 2724948,31236191,-16760175,-7268616,14799772,},}, - {{-28842672,4840636,-12047946,-9101456,-1445464, - 381905,-30977094,-16523389,1290540,12798615,}, - {27246947,-10320914,14792098,-14518944,5302070, - -8746152,-3403974,-4149637,-27061213,10749585,}, - {25572375,-6270368,-15353037,16037944,1146292, - 32198,23487090,9585613,24714571,-1418265,},}, - {{19844825,282124,-17583147,11004019,-32004269, - -2716035,6105106,-1711007,-21010044,14338445,}, - {8027505,8191102,-18504907,-12335737,25173494, - -5923905,15446145,7483684,-30440441,10009108,}, - {-14134701,-4174411,10246585,-14677495,33553567, - -14012935,23366126,15080531,-7969992,7663473,},}, -}; - -static const ge_precomp b_comb_high[8] = { - {{33055887,-4431773,-521787,6654165,951411, - -6266464,-5158124,6995613,-5397442,-6985227,}, - {4014062,6967095,-11977872,3960002,8001989, - 5130302,-2154812,-1899602,-31954493,-16173976,}, - {16271757,-9212948,23792794,731486,-25808309, - -3546396,6964344,-4767590,10976593,10050757,},}, - {{2533007,-4288439,-24467768,-12387405,-13450051, - 14542280,12876301,13893535,15067764,8594792,}, - {20073501,-11623621,3165391,-13119866,13188608, - -11540496,-10751437,-13482671,29588810,2197295,}, - {-1084082,11831693,6031797,14062724,14748428, - -8159962,-20721760,11742548,31368706,13161200,},}, - {{2050412,-6457589,15321215,5273360,25484180, - 124590,-18187548,-7097255,-6691621,-14604792,}, - {9938196,2162889,-6158074,-1711248,4278932, - -2598531,-22865792,-7168500,-24323168,11746309,}, - {-22691768,-14268164,5965485,9383325,20443693, - 5854192,28250679,-1381811,-10837134,13717818,},}, - {{-8495530,16382250,9548884,-4971523,-4491811, - -3902147,6182256,-12832479,26628081,10395408,}, - {27329048,-15853735,7715764,8717446,-9215518, - -14633480,28982250,-5668414,4227628,242148,}, - {-13279943,-7986904,-7100016,8764468,-27276630, - 3096719,29678419,-9141299,3906709,11265498,},}, - {{11918285,15686328,-17757323,-11217300,-27548967, - 4853165,-27168827,6807359,6871949,-1075745,}, - {-29002610,13984323,-27111812,-2713442,28107359, - -13266203,6155126,15104658,3538727,-7513788,}, - {14103158,11233913,-33165269,9279850,31014152, - 4335090,-1827936,4590951,13960841,12787712,},}, - {{1469134,-16738009,33411928,13942824,8092558, - -8778224,-11165065,1437842,22521552,-2792954,}, - {31352705,-4807352,-25327300,3962447,12541566, - -9399651,-27425693,7964818,-23829869,5541287,}, - {-25732021,-6864887,23848984,3039395,-9147354, - 6022816,-27421653,10590137,25309915,-1584678,},}, - {{-22951376,5048948,31139401,-190316,-19542447, - -626310,-17486305,-16511925,-18851313,-12985140,}, - {-9684890,14681754,30487568,7717771,-10829709, - 9630497,30290549,-10531496,-27798994,-13812825,}, - {5827835,16097107,-24501327,12094619,7413972, - 11447087,28057551,-1793987,-14056981,4359312,},}, - {{26323183,2342588,-21887793,-1623758,-6062284, - 2107090,-28724907,9036464,-19618351,-13055189,}, - {-29697200,14829398,-4596333,14220089,-30022969, - 2955645,12094100,-13693652,-5941445,7047569,}, - {-3201977,14413268,-12058324,-16417589,-9035655, - -7224648,9258160,1399236,30397584,-5684634,},}, -}; - -static void lookup_add(ge *p, ge_precomp *tmp_c, fe tmp_a, fe tmp_b, - const ge_precomp comb[8], const u8 scalar[32], int i) -{ - u8 teeth = (u8)((scalar_bit(scalar, i) ) + - (scalar_bit(scalar, i + 32) << 1) + - (scalar_bit(scalar, i + 64) << 2) + - (scalar_bit(scalar, i + 96) << 3)); - u8 high = teeth >> 3; - u8 index = (teeth ^ (high - 1)) & 7; - FOR (j, 0, 8) { - i32 select = 1 & (((j ^ index) - 1) >> 8); - fe_ccopy(tmp_c->Yp, comb[j].Yp, select); - fe_ccopy(tmp_c->Ym, comb[j].Ym, select); - fe_ccopy(tmp_c->T2, comb[j].T2, select); - } - fe_neg(tmp_a, tmp_c->T2); - fe_cswap(tmp_c->T2, tmp_a , high ^ 1); - fe_cswap(tmp_c->Yp, tmp_c->Ym, high ^ 1); - ge_madd(p, p, tmp_c, tmp_a, tmp_b); -} - -// p = [scalar]B, where B is the base point -static void ge_scalarmult_base(ge *p, const u8 scalar[32]) -{ - // twin 4-bits signed combs, from Mike Hamburg's - // Fast and compact elliptic-curve cryptography (2012) - // 1 / 2 modulo L - static const u8 half_mod_L[32] = { - 247,233,122,46,141,49,9,44,107,206,123,81,239,124,111,10, - 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,8, - }; - // (2^256 - 1) / 2 modulo L - static const u8 half_ones[32] = { - 142,74,204,70,186,24,118,107,184,231,190,57,250,173,119,99, - 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,7, - }; - - // All bits set form: 1 means 1, 0 means -1 - u8 s_scalar[32]; - crypto_eddsa_mul_add(s_scalar, scalar, half_mod_L, half_ones); - - // Double and add ladder - fe tmp_a, tmp_b; // temporaries for addition - ge_precomp tmp_c; // temporary for comb lookup - ge tmp_d; // temporary for doubling - fe_1(tmp_c.Yp); - fe_1(tmp_c.Ym); - fe_0(tmp_c.T2); - - // Save a double on the first iteration - ge_zero(p); - lookup_add(p, &tmp_c, tmp_a, tmp_b, b_comb_low , s_scalar, 31); - lookup_add(p, &tmp_c, tmp_a, tmp_b, b_comb_high, s_scalar, 31+128); - // Regular double & add for the rest - for (int i = 30; i >= 0; i--) { - ge_double(p, p, &tmp_d); - lookup_add(p, &tmp_c, tmp_a, tmp_b, b_comb_low , s_scalar, i); - lookup_add(p, &tmp_c, tmp_a, tmp_b, b_comb_high, s_scalar, i+128); - } - // Note: we could save one addition at the end if we assumed the - // scalar fit in 252 bits. Which it does in practice if it is - // selected at random. However, non-random, non-hashed scalars - // *can* overflow 252 bits in practice. Better account for that - // than leaving that kind of subtle corner case. - - WIPE_BUFFER(tmp_a); WIPE_CTX(&tmp_d); - WIPE_BUFFER(tmp_b); WIPE_CTX(&tmp_c); - WIPE_BUFFER(s_scalar); -} - -void crypto_eddsa_scalarbase(u8 point[32], const u8 scalar[32]) -{ - ge P; - ge_scalarmult_base(&P, scalar); - ge_tobytes(point, &P); - WIPE_CTX(&P); -} - -void crypto_eddsa_key_pair(u8 secret_key[64], u8 public_key[32], u8 seed[32]) -{ - // To allow overlaps, observable writes happen in this order: - // 1. seed - // 2. secret_key - // 3. public_key - u8 a[64]; - COPY(a, seed, 32); - crypto_wipe(seed, 32); - COPY(secret_key, a, 32); - crypto_blake2b(a, 64, a, 32); - crypto_eddsa_trim_scalar(a, a); - crypto_eddsa_scalarbase(secret_key + 32, a); - COPY(public_key, secret_key + 32, 32); - WIPE_BUFFER(a); -} - -static void hash_reduce(u8 h[32], - const u8 *a, size_t a_size, - const u8 *b, size_t b_size, - const u8 *c, size_t c_size) -{ - u8 hash[64]; - crypto_blake2b_ctx ctx; - crypto_blake2b_init (&ctx, 64); - crypto_blake2b_update(&ctx, a, a_size); - crypto_blake2b_update(&ctx, b, b_size); - crypto_blake2b_update(&ctx, c, c_size); - crypto_blake2b_final (&ctx, hash); - crypto_eddsa_reduce(h, hash); -} - -// Digital signature of a message with from a secret key. -// -// The secret key comprises two parts: -// - The seed that generates the key (secret_key[ 0..31]) -// - The public key (secret_key[32..63]) -// -// The seed and the public key are bundled together to make sure users -// don't use mismatched seeds and public keys, which would instantly -// leak the secret scalar and allow forgeries (allowing this to happen -// has resulted in critical vulnerabilities in the wild). -// -// The seed is hashed to derive the secret scalar and a secret prefix. -// The sole purpose of the prefix is to generate a secret random nonce. -// The properties of that nonce must be as follows: -// - Unique: we need a different one for each message. -// - Secret: third parties must not be able to predict it. -// - Random: any detectable bias would break all security. -// -// There are two ways to achieve these properties. The obvious one is -// to simply generate a random number. Here that would be a parameter -// (Monocypher doesn't have an RNG). It works, but then users may reuse -// the nonce by accident, which _also_ leaks the secret scalar and -// allows forgeries. This has happened in the wild too. -// -// This is no good, so instead we generate that nonce deterministically -// by reducing modulo L a hash of the secret prefix and the message. -// The secret prefix makes the nonce unpredictable, the message makes it -// unique, and the hash/reduce removes all bias. -// -// The cost of that safety is hashing the message twice. If that cost -// is unacceptable, there are two alternatives: -// -// - Signing a hash of the message instead of the message itself. This -// is fine as long as the hash is collision resistant. It is not -// compatible with existing "pure" signatures, but at least it's safe. -// -// - Using a random nonce. Please exercise **EXTREME CAUTION** if you -// ever do that. It is absolutely **critical** that the nonce is -// really an unbiased random number between 0 and L-1, never reused, -// and wiped immediately. -// -// To lower the likelihood of complete catastrophe if the RNG is -// either flawed or misused, you can hash the RNG output together with -// the secret prefix and the beginning of the message, and use the -// reduction of that hash instead of the RNG output itself. It's not -// foolproof (you'd need to hash the whole message) but it helps. -// -// Signing a message involves the following operations: -// -// scalar, prefix = HASH(secret_key) -// r = HASH(prefix || message) % L -// R = [r]B -// h = HASH(R || public_key || message) % L -// S = ((h * a) + r) % L -// signature = R || S -void crypto_eddsa_sign(u8 signature [64], const u8 secret_key[64], - const u8 *message, size_t message_size) -{ - u8 a[64]; // secret scalar and prefix - u8 r[32]; // secret deterministic "random" nonce - u8 h[32]; // publically verifiable hash of the message (not wiped) - u8 R[32]; // first half of the signature (allows overlapping inputs) - - crypto_blake2b(a, 64, secret_key, 32); - crypto_eddsa_trim_scalar(a, a); - hash_reduce(r, a + 32, 32, message, message_size, 0, 0); - crypto_eddsa_scalarbase(R, r); - hash_reduce(h, R, 32, secret_key + 32, 32, message, message_size); - COPY(signature, R, 32); - crypto_eddsa_mul_add(signature + 32, h, a, r); - - WIPE_BUFFER(a); - WIPE_BUFFER(r); -} - -// To check the signature R, S of the message M with the public key A, -// there are 3 steps: -// -// compute h = HASH(R || A || message) % L -// check that A is on the curve. -// check that R == [s]B - [h]A -// -// The last two steps are done in crypto_eddsa_check_equation() -int crypto_eddsa_check(const u8 signature[64], const u8 public_key[32], - const u8 *message, size_t message_size) -{ - u8 h[32]; - hash_reduce(h, signature, 32, public_key, 32, message, message_size); - return crypto_eddsa_check_equation(signature, public_key, h); -} - -///////////////////////// -/// EdDSA <--> X25519 /// -///////////////////////// -void crypto_eddsa_to_x25519(u8 x25519[32], const u8 eddsa[32]) -{ - // (u, v) = ((1+y)/(1-y), sqrt(-486664)*u/x) - // Only converting y to u, the sign of x is ignored. - fe t1, t2; - fe_frombytes(t2, eddsa); - fe_add(t1, fe_one, t2); - fe_sub(t2, fe_one, t2); - fe_invert(t2, t2); - fe_mul(t1, t1, t2); - fe_tobytes(x25519, t1); - WIPE_BUFFER(t1); - WIPE_BUFFER(t2); -} - -void crypto_x25519_to_eddsa(u8 eddsa[32], const u8 x25519[32]) -{ - // (x, y) = (sqrt(-486664)*u/v, (u-1)/(u+1)) - // Only converting u to y, x is assumed positive. - fe t1, t2; - fe_frombytes(t2, x25519); - fe_sub(t1, t2, fe_one); - fe_add(t2, t2, fe_one); - fe_invert(t2, t2); - fe_mul(t1, t1, t2); - fe_tobytes(eddsa, t1); - WIPE_BUFFER(t1); - WIPE_BUFFER(t2); -} - -///////////////////////////////////////////// -/// Dirty ephemeral public key generation /// -///////////////////////////////////////////// - -// Those functions generates a public key, *without* clearing the -// cofactor. Sending that key over the network leaks 3 bits of the -// private key. Use only to generate ephemeral keys that will be hidden -// with crypto_curve_to_hidden(). -// -// The public key is otherwise compatible with crypto_x25519(), which -// properly clears the cofactor. -// -// Note that the distribution of the resulting public keys is almost -// uniform. Flipping the sign of the v coordinate (not provided by this -// function), covers the entire key space almost perfectly, where -// "almost" means a 2^-128 bias (undetectable). This uniformity is -// needed to ensure the proper randomness of the resulting -// representatives (once we apply crypto_curve_to_hidden()). -// -// Recall that Curve25519 has order C = 2^255 + e, with e < 2^128 (not -// to be confused with the prime order of the main subgroup, L, which is -// 8 times less than that). -// -// Generating all points would require us to multiply a point of order C -// (the base point plus any point of order 8) by all scalars from 0 to -// C-1. Clamping limits us to scalars between 2^254 and 2^255 - 1. But -// by negating the resulting point at random, we also cover scalars from -// -2^255 + 1 to -2^254 (which modulo C is congruent to e+1 to 2^254 + e). -// -// In practice: -// - Scalars from 0 to e + 1 are never generated -// - Scalars from 2^255 to 2^255 + e are never generated -// - Scalars from 2^254 + 1 to 2^254 + e are generated twice -// -// Since e < 2^128, detecting this bias requires observing over 2^100 -// representatives from a given source (this will never happen), *and* -// recovering enough of the private key to determine that they do, or do -// not, belong to the biased set (this practically requires solving -// discrete logarithm, which is conjecturally intractable). -// -// In practice, this means the bias is impossible to detect. - -// s + (x*L) % 8*L -// Guaranteed to fit in 256 bits iff s fits in 255 bits. -// L < 2^253 -// x%8 < 2^3 -// L * (x%8) < 2^255 -// s < 2^255 -// s + L * (x%8) < 2^256 -static void add_xl(u8 s[32], u8 x) -{ - u64 mod8 = x & 7; - u64 carry = 0; - FOR (i , 0, 8) { - carry = carry + load32_le(s + 4*i) + L[i] * mod8; - store32_le(s + 4*i, (u32)carry); - carry >>= 32; - } -} - -// "Small" dirty ephemeral key. -// Use if you need to shrink the size of the binary, and can afford to -// slow down by a factor of two (compared to the fast version) -// -// This version works by decoupling the cofactor from the main factor. -// -// - The trimmed scalar determines the main factor -// - The clamped bits of the scalar determine the cofactor. -// -// Cofactor and main factor are combined into a single scalar, which is -// then multiplied by a point of order 8*L (unlike the base point, which -// has prime order). That "dirty" base point is the addition of the -// regular base point (9), and a point of order 8. -void crypto_x25519_dirty_small(u8 public_key[32], const u8 secret_key[32]) -{ - // Base point of order 8*L - // Raw scalar multiplication with it does not clear the cofactor, - // and the resulting public key will reveal 3 bits of the scalar. - // - // The low order component of this base point has been chosen - // to yield the same results as crypto_x25519_dirty_fast(). - static const u8 dirty_base_point[32] = { - 0xd8, 0x86, 0x1a, 0xa2, 0x78, 0x7a, 0xd9, 0x26, - 0x8b, 0x74, 0x74, 0xb6, 0x82, 0xe3, 0xbe, 0xc3, - 0xce, 0x36, 0x9a, 0x1e, 0x5e, 0x31, 0x47, 0xa2, - 0x6d, 0x37, 0x7c, 0xfd, 0x20, 0xb5, 0xdf, 0x75, - }; - // separate the main factor & the cofactor of the scalar - u8 scalar[32]; - crypto_eddsa_trim_scalar(scalar, secret_key); - - // Separate the main factor and the cofactor - // - // The scalar is trimmed, so its cofactor is cleared. The three - // least significant bits however still have a main factor. We must - // remove it for X25519 compatibility. - // - // cofactor = lsb * L (modulo 8*L) - // combined = scalar + cofactor (modulo 8*L) - add_xl(scalar, secret_key[0]); - scalarmult(public_key, scalar, dirty_base_point, 256); - WIPE_BUFFER(scalar); -} - -// Select low order point -// We're computing the [cofactor]lop scalar multiplication, where: -// -// cofactor = tweak & 7. -// lop = (lop_x, lop_y) -// lop_x = sqrt((sqrt(d + 1) + 1) / d) -// lop_y = -lop_x * sqrtm1 -// -// The low order point has order 8. There are 4 such points. We've -// chosen the one whose both coordinates are positive (below p/2). -// The 8 low order points are as follows: -// -// [0]lop = ( 0 , 1 ) -// [1]lop = ( lop_x , lop_y) -// [2]lop = ( sqrt(-1), -0 ) -// [3]lop = ( lop_x , -lop_y) -// [4]lop = (-0 , -1 ) -// [5]lop = (-lop_x , -lop_y) -// [6]lop = (-sqrt(-1), 0 ) -// [7]lop = (-lop_x , lop_y) -// -// The x coordinate is either 0, sqrt(-1), lop_x, or their opposite. -// The y coordinate is either 0, -1 , lop_y, or their opposite. -// The pattern for both is the same, except for a rotation of 2 (modulo 8) -// -// This helper function captures the pattern, and we can use it thus: -// -// select_lop(x, lop_x, sqrtm1, cofactor); -// select_lop(y, lop_y, fe_one, cofactor + 2); -// -// This is faster than an actual scalar multiplication, -// and requires less code than naive constant time look up. -static void select_lop(fe out, const fe x, const fe k, u8 cofactor) -{ - fe tmp; - fe_0(out); - fe_ccopy(out, k , (cofactor >> 1) & 1); // bit 1 - fe_ccopy(out, x , (cofactor >> 0) & 1); // bit 0 - fe_neg (tmp, out); - fe_ccopy(out, tmp, (cofactor >> 2) & 1); // bit 2 - WIPE_BUFFER(tmp); -} - -// "Fast" dirty ephemeral key -// We use this one by default. -// -// This version works by performing a regular scalar multiplication, -// then add a low order point. The scalar multiplication is done in -// Edwards space for more speed (*2 compared to the "small" version). -// The cost is a bigger binary for programs that don't also sign messages. -void crypto_x25519_dirty_fast(u8 public_key[32], const u8 secret_key[32]) -{ - // Compute clean scalar multiplication - u8 scalar[32]; - ge pk; - crypto_eddsa_trim_scalar(scalar, secret_key); - ge_scalarmult_base(&pk, scalar); - - // Compute low order point - fe t1, t2; - select_lop(t1, lop_x, sqrtm1, secret_key[0]); - select_lop(t2, lop_y, fe_one, secret_key[0] + 2); - ge_precomp low_order_point; - fe_add(low_order_point.Yp, t2, t1); - fe_sub(low_order_point.Ym, t2, t1); - fe_mul(low_order_point.T2, t2, t1); - fe_mul(low_order_point.T2, low_order_point.T2, D2); - - // Add low order point to the public key - ge_madd(&pk, &pk, &low_order_point, t1, t2); - - // Convert to Montgomery u coordinate (we ignore the sign) - fe_add(t1, pk.Z, pk.Y); - fe_sub(t2, pk.Z, pk.Y); - fe_invert(t2, t2); - fe_mul(t1, t1, t2); - - fe_tobytes(public_key, t1); - - WIPE_BUFFER(t1); WIPE_CTX(&pk); - WIPE_BUFFER(t2); WIPE_CTX(&low_order_point); - WIPE_BUFFER(scalar); -} - -/////////////////// -/// Elligator 2 /// -/////////////////// -static const fe A = {486662}; - -// Elligator direct map -// -// Computes the point corresponding to a representative, encoded in 32 -// bytes (little Endian). Since positive representatives fits in 254 -// bits, The two most significant bits are ignored. -// -// From the paper: -// w = -A / (fe(1) + non_square * r^2) -// e = chi(w^3 + A*w^2 + w) -// u = e*w - (fe(1)-e)*(A//2) -// v = -e * sqrt(u^3 + A*u^2 + u) -// -// We ignore v because we don't need it for X25519 (the Montgomery -// ladder only uses u). -// -// Note that e is either 0, 1 or -1 -// if e = 0 u = 0 and v = 0 -// if e = 1 u = w -// if e = -1 u = -w - A = w * non_square * r^2 -// -// Let r1 = non_square * r^2 -// Let r2 = 1 + r1 -// Note that r2 cannot be zero, -1/non_square is not a square. -// We can (tediously) verify that: -// w^3 + A*w^2 + w = (A^2*r1 - r2^2) * A / r2^3 -// Therefore: -// chi(w^3 + A*w^2 + w) = chi((A^2*r1 - r2^2) * (A / r2^3)) -// chi(w^3 + A*w^2 + w) = chi((A^2*r1 - r2^2) * (A / r2^3)) * 1 -// chi(w^3 + A*w^2 + w) = chi((A^2*r1 - r2^2) * (A / r2^3)) * chi(r2^6) -// chi(w^3 + A*w^2 + w) = chi((A^2*r1 - r2^2) * (A / r2^3) * r2^6) -// chi(w^3 + A*w^2 + w) = chi((A^2*r1 - r2^2) * A * r2^3) -// Corollary: -// e = 1 if (A^2*r1 - r2^2) * A * r2^3) is a non-zero square -// e = -1 if (A^2*r1 - r2^2) * A * r2^3) is not a square -// Note that w^3 + A*w^2 + w (and therefore e) can never be zero: -// w^3 + A*w^2 + w = w * (w^2 + A*w + 1) -// w^3 + A*w^2 + w = w * (w^2 + A*w + A^2/4 - A^2/4 + 1) -// w^3 + A*w^2 + w = w * (w + A/2)^2 - A^2/4 + 1) -// which is zero only if: -// w = 0 (impossible) -// (w + A/2)^2 = A^2/4 - 1 (impossible, because A^2/4-1 is not a square) -// -// Let isr = invsqrt((A^2*r1 - r2^2) * A * r2^3) -// isr = sqrt(1 / ((A^2*r1 - r2^2) * A * r2^3)) if e = 1 -// isr = sqrt(sqrt(-1) / ((A^2*r1 - r2^2) * A * r2^3)) if e = -1 -// -// if e = 1 -// let u1 = -A * (A^2*r1 - r2^2) * A * r2^2 * isr^2 -// u1 = w -// u1 = u -// -// if e = -1 -// let ufactor = -non_square * sqrt(-1) * r^2 -// let vfactor = sqrt(ufactor) -// let u2 = -A * (A^2*r1 - r2^2) * A * r2^2 * isr^2 * ufactor -// u2 = w * -1 * -non_square * r^2 -// u2 = w * non_square * r^2 -// u2 = u -void crypto_elligator_map(u8 curve[32], const u8 hidden[32]) -{ - fe r, u, t1, t2, t3; - fe_frombytes_mask(r, hidden, 2); // r is encoded in 254 bits. - fe_sq(r, r); - fe_add(t1, r, r); - fe_add(u, t1, fe_one); - fe_sq (t2, u); - fe_mul(t3, A2, t1); - fe_sub(t3, t3, t2); - fe_mul(t3, t3, A); - fe_mul(t1, t2, u); - fe_mul(t1, t3, t1); - int is_square = invsqrt(t1, t1); - fe_mul(u, r, ufactor); - fe_ccopy(u, fe_one, is_square); - fe_sq (t1, t1); - fe_mul(u, u, A); - fe_mul(u, u, t3); - fe_mul(u, u, t2); - fe_mul(u, u, t1); - fe_neg(u, u); - fe_tobytes(curve, u); - - WIPE_BUFFER(t1); WIPE_BUFFER(r); - WIPE_BUFFER(t2); WIPE_BUFFER(u); - WIPE_BUFFER(t3); -} - -// Elligator inverse map -// -// Computes the representative of a point, if possible. If not, it does -// nothing and returns -1. Note that the success of the operation -// depends only on the point (more precisely its u coordinate). The -// tweak parameter is used only upon success -// -// The tweak should be a random byte. Beyond that, its contents are an -// implementation detail. Currently, the tweak comprises: -// - Bit 1 : sign of the v coordinate (0 if positive, 1 if negative) -// - Bit 2-5: not used -// - Bits 6-7: random padding -// -// From the paper: -// Let sq = -non_square * u * (u+A) -// if sq is not a square, or u = -A, there is no mapping -// Assuming there is a mapping: -// if v is positive: r = sqrt(-u / (non_square * (u+A))) -// if v is negative: r = sqrt(-(u+A) / (non_square * u )) -// -// We compute isr = invsqrt(-non_square * u * (u+A)) -// if it wasn't a square, abort. -// else, isr = sqrt(-1 / (non_square * u * (u+A)) -// -// If v is positive, we return isr * u: -// isr * u = sqrt(-1 / (non_square * u * (u+A)) * u -// isr * u = sqrt(-u / (non_square * (u+A)) -// -// If v is negative, we return isr * (u+A): -// isr * (u+A) = sqrt(-1 / (non_square * u * (u+A)) * (u+A) -// isr * (u+A) = sqrt(-(u+A) / (non_square * u) -int crypto_elligator_rev(u8 hidden[32], const u8 public_key[32], u8 tweak) -{ - fe t1, t2, t3; - fe_frombytes(t1, public_key); // t1 = u - - fe_add(t2, t1, A); // t2 = u + A - fe_mul(t3, t1, t2); - fe_mul_small(t3, t3, -2); - int is_square = invsqrt(t3, t3); // t3 = sqrt(-1 / non_square * u * (u+A)) - if (is_square) { - // The only variable time bit. This ultimately reveals how many - // tries it took us to find a representable key. - // This does not affect security as long as we try keys at random. - - fe_ccopy (t1, t2, tweak & 1); // multiply by u if v is positive, - fe_mul (t3, t1, t3); // multiply by u+A otherwise - fe_mul_small(t1, t3, 2); - fe_neg (t2, t3); - fe_ccopy (t3, t2, fe_isodd(t1)); - fe_tobytes(hidden, t3); - - // Pad with two random bits - hidden[31] |= tweak & 0xc0; - } - - WIPE_BUFFER(t1); - WIPE_BUFFER(t2); - WIPE_BUFFER(t3); - return is_square - 1; -} - -void crypto_elligator_key_pair(u8 hidden[32], u8 secret_key[32], u8 seed[32]) -{ - u8 pk [32]; // public key - u8 buf[64]; // seed + representative - COPY(buf + 32, seed, 32); - do { - crypto_chacha20_djb(buf, 0, 64, buf+32, zero, 0); - crypto_x25519_dirty_fast(pk, buf); // or the "small" version - } while(crypto_elligator_rev(buf+32, pk, buf[32])); - // Note that the return value of crypto_elligator_rev() is - // independent from its tweak parameter. - // Therefore, buf[32] is not actually reused. Either we loop one - // more time and buf[32] is used for the new seed, or we succeeded, - // and buf[32] becomes the tweak parameter. - - crypto_wipe(seed, 32); - COPY(hidden , buf + 32, 32); - COPY(secret_key, buf , 32); - WIPE_BUFFER(buf); - WIPE_BUFFER(pk); -} - -/////////////////////// -/// Scalar division /// -/////////////////////// - -// Montgomery reduction. -// Divides x by (2^256), and reduces the result modulo L -// -// Precondition: -// x < L * 2^256 -// Constants: -// r = 2^256 (makes division by r trivial) -// k = (r * (1/r) - 1) // L (1/r is computed modulo L ) -// Algorithm: -// s = (x * k) % r -// t = x + s*L (t is always a multiple of r) -// u = (t/r) % L (u is always below 2*L, conditional subtraction is enough) -static void redc(u32 u[8], u32 x[16]) -{ - static const u32 k[8] = { - 0x12547e1b, 0xd2b51da3, 0xfdba84ff, 0xb1a206f2, - 0xffa36bea, 0x14e75438, 0x6fe91836, 0x9db6c6f2, - }; - - // s = x * k (modulo 2^256) - // This is cheaper than the full multiplication. - u32 s[8] = {0}; - FOR (i, 0, 8) { - u64 carry = 0; - FOR (j, 0, 8-i) { - carry += s[i+j] + (u64)x[i] * k[j]; - s[i+j] = (u32)carry; - carry >>= 32; - } - } - u32 t[16] = {0}; - multiply(t, s, L); - - // t = t + x - u64 carry = 0; - FOR (i, 0, 16) { - carry += (u64)t[i] + x[i]; - t[i] = (u32)carry; - carry >>= 32; - } - - // u = (t / 2^256) % L - // Note that t / 2^256 is always below 2*L, - // So a constant time conditional subtraction is enough - remove_l(u, t+8); - - WIPE_BUFFER(s); - WIPE_BUFFER(t); -} - -void crypto_x25519_inverse(u8 blind_salt [32], const u8 private_key[32], - const u8 curve_point[32]) -{ - static const u8 Lm2[32] = { // L - 2 - 0xeb, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, - 0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9, 0xde, 0x14, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, - }; - // 1 in Montgomery form - u32 m_inv [8] = { - 0x8d98951d, 0xd6ec3174, 0x737dcf70, 0xc6ef5bf4, - 0xfffffffe, 0xffffffff, 0xffffffff, 0x0fffffff, - }; - - u8 scalar[32]; - crypto_eddsa_trim_scalar(scalar, private_key); - - // Convert the scalar in Montgomery form - // m_scl = scalar * 2^256 (modulo L) - u32 m_scl[8]; - { - u32 tmp[16]; - ZERO(tmp, 8); - load32_le_buf(tmp+8, scalar, 8); - mod_l(scalar, tmp); - load32_le_buf(m_scl, scalar, 8); - WIPE_BUFFER(tmp); // Wipe ASAP to save stack space - } - - // Compute the inverse - u32 product[16]; - for (int i = 252; i >= 0; i--) { - ZERO(product, 16); - multiply(product, m_inv, m_inv); - redc(m_inv, product); - if (scalar_bit(Lm2, i)) { - ZERO(product, 16); - multiply(product, m_inv, m_scl); - redc(m_inv, product); - } - } - // Convert the inverse *out* of Montgomery form - // scalar = m_inv / 2^256 (modulo L) - COPY(product, m_inv, 8); - ZERO(product + 8, 8); - redc(m_inv, product); - store32_le_buf(scalar, m_inv, 8); // the *inverse* of the scalar - - // Clear the cofactor of scalar: - // cleared = scalar * (3*L + 1) (modulo 8*L) - // cleared = scalar + scalar * 3 * L (modulo 8*L) - // Note that (scalar * 3) is reduced modulo 8, so we only need the - // first byte. - add_xl(scalar, scalar[0] * 3); - - // Recall that 8*L < 2^256. However it is also very close to - // 2^255. If we spanned the ladder over 255 bits, random tests - // wouldn't catch the off-by-one error. - scalarmult(blind_salt, scalar, curve_point, 256); - - WIPE_BUFFER(scalar); WIPE_BUFFER(m_scl); - WIPE_BUFFER(product); WIPE_BUFFER(m_inv); -} - -//////////////////////////////// -/// Authenticated encryption /// -//////////////////////////////// -static void lock_auth(u8 mac[16], const u8 auth_key[32], - const u8 *ad , size_t ad_size, - const u8 *cipher_text, size_t text_size) -{ - u8 sizes[16]; // Not secret, not wiped - store64_le(sizes + 0, ad_size); - store64_le(sizes + 8, text_size); - crypto_poly1305_ctx poly_ctx; // auto wiped... - crypto_poly1305_init (&poly_ctx, auth_key); - crypto_poly1305_update(&poly_ctx, ad , ad_size); - crypto_poly1305_update(&poly_ctx, zero , gap(ad_size, 16)); - crypto_poly1305_update(&poly_ctx, cipher_text, text_size); - crypto_poly1305_update(&poly_ctx, zero , gap(text_size, 16)); - crypto_poly1305_update(&poly_ctx, sizes , 16); - crypto_poly1305_final (&poly_ctx, mac); // ...here -} - -void crypto_aead_init_x(crypto_aead_ctx *ctx, - u8 const key[32], const u8 nonce[24]) -{ - crypto_chacha20_h(ctx->key, key, nonce); - COPY(ctx->nonce, nonce + 16, 8); - ctx->counter = 0; -} - -void crypto_aead_init_djb(crypto_aead_ctx *ctx, - const u8 key[32], const u8 nonce[8]) -{ - COPY(ctx->key , key , 32); - COPY(ctx->nonce, nonce, 8); - ctx->counter = 0; -} - -void crypto_aead_init_ietf(crypto_aead_ctx *ctx, - const u8 key[32], const u8 nonce[12]) -{ - COPY(ctx->key , key , 32); - COPY(ctx->nonce, nonce + 4, 8); - ctx->counter = (u64)load32_le(nonce) << 32; -} - -void crypto_aead_write(crypto_aead_ctx *ctx, u8 *cipher_text, u8 mac[16], - const u8 *ad, size_t ad_size, - const u8 *plain_text, size_t text_size) -{ - u8 auth_key[64]; // the last 32 bytes are used for rekeying. - crypto_chacha20_djb(auth_key, 0, 64, ctx->key, ctx->nonce, ctx->counter); - crypto_chacha20_djb(cipher_text, plain_text, text_size, - ctx->key, ctx->nonce, ctx->counter + 1); - lock_auth(mac, auth_key, ad, ad_size, cipher_text, text_size); - COPY(ctx->key, auth_key + 32, 32); - WIPE_BUFFER(auth_key); -} - -int crypto_aead_read(crypto_aead_ctx *ctx, u8 *plain_text, const u8 mac[16], - const u8 *ad, size_t ad_size, - const u8 *cipher_text, size_t text_size) -{ - u8 auth_key[64]; // the last 32 bytes are used for rekeying. - u8 real_mac[16]; - crypto_chacha20_djb(auth_key, 0, 64, ctx->key, ctx->nonce, ctx->counter); - lock_auth(real_mac, auth_key, ad, ad_size, cipher_text, text_size); - int mismatch = crypto_verify16(mac, real_mac); - if (!mismatch) { - crypto_chacha20_djb(plain_text, cipher_text, text_size, - ctx->key, ctx->nonce, ctx->counter + 1); - COPY(ctx->key, auth_key + 32, 32); - } - WIPE_BUFFER(auth_key); - WIPE_BUFFER(real_mac); - return mismatch; -} - -void crypto_aead_lock(u8 *cipher_text, u8 mac[16], const u8 key[32], - const u8 nonce[24], const u8 *ad, size_t ad_size, - const u8 *plain_text, size_t text_size) -{ - crypto_aead_ctx ctx; - crypto_aead_init_x(&ctx, key, nonce); - crypto_aead_write(&ctx, cipher_text, mac, ad, ad_size, - plain_text, text_size); - crypto_wipe(&ctx, sizeof(ctx)); -} - -int crypto_aead_unlock(u8 *plain_text, const u8 mac[16], const u8 key[32], - const u8 nonce[24], const u8 *ad, size_t ad_size, - const u8 *cipher_text, size_t text_size) -{ - crypto_aead_ctx ctx; - crypto_aead_init_x(&ctx, key, nonce); - int mismatch = crypto_aead_read(&ctx, plain_text, mac, ad, ad_size, - cipher_text, text_size); - crypto_wipe(&ctx, sizeof(ctx)); - return mismatch; -} - -#ifdef MONOCYPHER_CPP_NAMESPACE -} -#endif diff --git a/monocypher.h b/monocypher.h deleted file mode 100644 index 765a07f..0000000 --- a/monocypher.h +++ /dev/null @@ -1,321 +0,0 @@ -// Monocypher version 4.0.2 -// -// This file is dual-licensed. Choose whichever licence you want from -// the two licences listed below. -// -// The first licence is a regular 2-clause BSD licence. The second licence -// is the CC-0 from Creative Commons. It is intended to release Monocypher -// to the public domain. The BSD licence serves as a fallback option. -// -// SPDX-License-Identifier: BSD-2-Clause OR CC0-1.0 -// -// ------------------------------------------------------------------------ -// -// Copyright (c) 2017-2019, Loup Vaillant -// All rights reserved. -// -// -// Redistribution and use in source and binary forms, with or without -// modification, are permitted provided that the following conditions are -// met: -// -// 1. Redistributions of source code must retain the above copyright -// notice, this list of conditions and the following disclaimer. -// -// 2. Redistributions in binary form must reproduce the above copyright -// notice, this list of conditions and the following disclaimer in the -// documentation and/or other materials provided with the -// distribution. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT -// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -// -// ------------------------------------------------------------------------ -// -// Written in 2017-2019 by Loup Vaillant -// -// To the extent possible under law, the author(s) have dedicated all copyright -// and related neighboring rights to this software to the public domain -// worldwide. This software is distributed without any warranty. -// -// You should have received a copy of the CC0 Public Domain Dedication along -// with this software. If not, see -// - -#ifndef MONOCYPHER_H -#define MONOCYPHER_H - -#include -#include - -#ifdef MONOCYPHER_CPP_NAMESPACE -namespace MONOCYPHER_CPP_NAMESPACE { -#elif defined(__cplusplus) -extern "C" { -#endif - -// Constant time comparisons -// ------------------------- - -// Return 0 if a and b are equal, -1 otherwise -int crypto_verify16(const uint8_t a[16], const uint8_t b[16]); -int crypto_verify32(const uint8_t a[32], const uint8_t b[32]); -int crypto_verify64(const uint8_t a[64], const uint8_t b[64]); - - -// Erase sensitive data -// -------------------- -void crypto_wipe(void *secret, size_t size); - - -// Authenticated encryption -// ------------------------ -void crypto_aead_lock(uint8_t *cipher_text, - uint8_t mac [16], - const uint8_t key [32], - const uint8_t nonce[24], - const uint8_t *ad, size_t ad_size, - const uint8_t *plain_text, size_t text_size); -int crypto_aead_unlock(uint8_t *plain_text, - const uint8_t mac [16], - const uint8_t key [32], - const uint8_t nonce[24], - const uint8_t *ad, size_t ad_size, - const uint8_t *cipher_text, size_t text_size); - -// Authenticated stream -// -------------------- -typedef struct { - uint64_t counter; - uint8_t key[32]; - uint8_t nonce[8]; -} crypto_aead_ctx; - -void crypto_aead_init_x(crypto_aead_ctx *ctx, - const uint8_t key[32], const uint8_t nonce[24]); -void crypto_aead_init_djb(crypto_aead_ctx *ctx, - const uint8_t key[32], const uint8_t nonce[8]); -void crypto_aead_init_ietf(crypto_aead_ctx *ctx, - const uint8_t key[32], const uint8_t nonce[12]); - -void crypto_aead_write(crypto_aead_ctx *ctx, - uint8_t *cipher_text, - uint8_t mac[16], - const uint8_t *ad , size_t ad_size, - const uint8_t *plain_text, size_t text_size); -int crypto_aead_read(crypto_aead_ctx *ctx, - uint8_t *plain_text, - const uint8_t mac[16], - const uint8_t *ad , size_t ad_size, - const uint8_t *cipher_text, size_t text_size); - - -// General purpose hash (BLAKE2b) -// ------------------------------ - -// Direct interface -void crypto_blake2b(uint8_t *hash, size_t hash_size, - const uint8_t *message, size_t message_size); - -void crypto_blake2b_keyed(uint8_t *hash, size_t hash_size, - const uint8_t *key, size_t key_size, - const uint8_t *message, size_t message_size); - -// Incremental interface -typedef struct { - // Do not rely on the size or contents of this type, - // for they may change without notice. - uint64_t hash[8]; - uint64_t input_offset[2]; - uint64_t input[16]; - size_t input_idx; - size_t hash_size; -} crypto_blake2b_ctx; - -void crypto_blake2b_init(crypto_blake2b_ctx *ctx, size_t hash_size); -void crypto_blake2b_keyed_init(crypto_blake2b_ctx *ctx, size_t hash_size, - const uint8_t *key, size_t key_size); -void crypto_blake2b_update(crypto_blake2b_ctx *ctx, - const uint8_t *message, size_t message_size); -void crypto_blake2b_final(crypto_blake2b_ctx *ctx, uint8_t *hash); - - -// Password key derivation (Argon2) -// -------------------------------- -#define CRYPTO_ARGON2_D 0 -#define CRYPTO_ARGON2_I 1 -#define CRYPTO_ARGON2_ID 2 - -typedef struct { - uint32_t algorithm; // Argon2d, Argon2i, Argon2id - uint32_t nb_blocks; // memory hardness, >= 8 * nb_lanes - uint32_t nb_passes; // CPU hardness, >= 1 (>= 3 recommended for Argon2i) - uint32_t nb_lanes; // parallelism level (single threaded anyway) -} crypto_argon2_config; - -typedef struct { - const uint8_t *pass; - const uint8_t *salt; - uint32_t pass_size; - uint32_t salt_size; // 16 bytes recommended -} crypto_argon2_inputs; - -typedef struct { - const uint8_t *key; // may be NULL if no key - const uint8_t *ad; // may be NULL if no additional data - uint32_t key_size; // 0 if no key (32 bytes recommended otherwise) - uint32_t ad_size; // 0 if no additional data -} crypto_argon2_extras; - -extern const crypto_argon2_extras crypto_argon2_no_extras; - -void crypto_argon2(uint8_t *hash, uint32_t hash_size, void *work_area, - crypto_argon2_config config, - crypto_argon2_inputs inputs, - crypto_argon2_extras extras); - - -// Key exchange (X-25519) -// ---------------------- - -// Shared secrets are not quite random. -// Hash them to derive an actual shared key. -void crypto_x25519_public_key(uint8_t public_key[32], - const uint8_t secret_key[32]); -void crypto_x25519(uint8_t raw_shared_secret[32], - const uint8_t your_secret_key [32], - const uint8_t their_public_key [32]); - -// Conversion to EdDSA -void crypto_x25519_to_eddsa(uint8_t eddsa[32], const uint8_t x25519[32]); - -// scalar "division" -// Used for OPRF. Be aware that exponential blinding is less secure -// than Diffie-Hellman key exchange. -void crypto_x25519_inverse(uint8_t blind_salt [32], - const uint8_t private_key[32], - const uint8_t curve_point[32]); - -// "Dirty" versions of x25519_public_key(). -// Use with crypto_elligator_rev(). -// Leaks 3 bits of the private key. -void crypto_x25519_dirty_small(uint8_t pk[32], const uint8_t sk[32]); -void crypto_x25519_dirty_fast (uint8_t pk[32], const uint8_t sk[32]); - - -// Signatures -// ---------- - -// EdDSA with curve25519 + BLAKE2b -void crypto_eddsa_key_pair(uint8_t secret_key[64], - uint8_t public_key[32], - uint8_t seed[32]); -void crypto_eddsa_sign(uint8_t signature [64], - const uint8_t secret_key[64], - const uint8_t *message, size_t message_size); -int crypto_eddsa_check(const uint8_t signature [64], - const uint8_t public_key[32], - const uint8_t *message, size_t message_size); - -// Conversion to X25519 -void crypto_eddsa_to_x25519(uint8_t x25519[32], const uint8_t eddsa[32]); - -// EdDSA building blocks -void crypto_eddsa_trim_scalar(uint8_t out[32], const uint8_t in[32]); -void crypto_eddsa_reduce(uint8_t reduced[32], const uint8_t expanded[64]); -void crypto_eddsa_mul_add(uint8_t r[32], - const uint8_t a[32], - const uint8_t b[32], - const uint8_t c[32]); -void crypto_eddsa_scalarbase(uint8_t point[32], const uint8_t scalar[32]); -int crypto_eddsa_check_equation(const uint8_t signature[64], - const uint8_t public_key[32], - const uint8_t h_ram[32]); - - -// Chacha20 -// -------- - -// Specialised hash. -// Used to hash X25519 shared secrets. -void crypto_chacha20_h(uint8_t out[32], - const uint8_t key[32], - const uint8_t in [16]); - -// Unauthenticated stream cipher. -// Don't forget to add authentication. -uint64_t crypto_chacha20_djb(uint8_t *cipher_text, - const uint8_t *plain_text, - size_t text_size, - const uint8_t key[32], - const uint8_t nonce[8], - uint64_t ctr); -uint32_t crypto_chacha20_ietf(uint8_t *cipher_text, - const uint8_t *plain_text, - size_t text_size, - const uint8_t key[32], - const uint8_t nonce[12], - uint32_t ctr); -uint64_t crypto_chacha20_x(uint8_t *cipher_text, - const uint8_t *plain_text, - size_t text_size, - const uint8_t key[32], - const uint8_t nonce[24], - uint64_t ctr); - - -// Poly 1305 -// --------- - -// This is a *one time* authenticator. -// Disclosing the mac reveals the key. -// See crypto_lock() on how to use it properly. - -// Direct interface -void crypto_poly1305(uint8_t mac[16], - const uint8_t *message, size_t message_size, - const uint8_t key[32]); - -// Incremental interface -typedef struct { - // Do not rely on the size or contents of this type, - // for they may change without notice. - uint8_t c[16]; // chunk of the message - size_t c_idx; // How many bytes are there in the chunk. - uint32_t r [4]; // constant multiplier (from the secret key) - uint32_t pad[4]; // random number added at the end (from the secret key) - uint32_t h [5]; // accumulated hash -} crypto_poly1305_ctx; - -void crypto_poly1305_init (crypto_poly1305_ctx *ctx, const uint8_t key[32]); -void crypto_poly1305_update(crypto_poly1305_ctx *ctx, - const uint8_t *message, size_t message_size); -void crypto_poly1305_final (crypto_poly1305_ctx *ctx, uint8_t mac[16]); - - -// Elligator 2 -// ----------- - -// Elligator mappings proper -void crypto_elligator_map(uint8_t curve [32], const uint8_t hidden[32]); -int crypto_elligator_rev(uint8_t hidden[32], const uint8_t curve [32], - uint8_t tweak); - -// Easy to use key pair generation -void crypto_elligator_key_pair(uint8_t hidden[32], uint8_t secret_key[32], - uint8_t seed[32]); - -#ifdef __cplusplus -} -#endif - -#endif // MONOCYPHER_H