/* scrypt.c - Scrypt password-based key derivation function. * Copyright (C) 2012 Simon Josefsson * Copyright (C) 2013 Christian Grothoff * Copyright (C) 2013 g10 Code GmbH * * This file is part of Libgcrypt. * * Libgcrypt is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser general Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * Libgcrypt is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, see . */ /* Adapted from the nettle, low-level cryptographics library for * libgcrypt by Christian Grothoff; original license: * * Copyright (C) 2012 Simon Josefsson * * The nettle library is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or (at your * option) any later version. * * The nettle library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public * License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with the nettle library; see the file COPYING.LIB. If not, write to * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02111-1301, USA. */ #include #include #include #include #include "g10lib.h" #include "kdf-internal.h" #include "bufhelp.h" /* We really need a 64 bit type for this code. */ #define SALSA20_INPUT_LENGTH 16 #define ROTL32(n,x) (((x)<<(n)) | ((x)>>(32-(n)))) /* Reads a 64-bit integer, in network, big-endian, byte order */ #define READ_UINT64(p) buf_get_be64(p) /* And the other, little-endian, byteorder */ #define LE_READ_UINT64(p) buf_get_le64(p) #define LE_SWAP32(v) le_bswap32(v) #define QROUND(x0, x1, x2, x3) do { \ x1 ^= ROTL32(7, x0 + x3); \ x2 ^= ROTL32(9, x1 + x0); \ x3 ^= ROTL32(13, x2 + x1); \ x0 ^= ROTL32(18, x3 + x2); \ } while(0) static void salsa20_core (u32 *dst, const u32 *src, unsigned int rounds) { u32 x[SALSA20_INPUT_LENGTH]; unsigned i; assert ( (rounds & 1) == 0); for (i = 0; i < SALSA20_INPUT_LENGTH; i++) x[i] = LE_SWAP32(src[i]); for (i = 0; i < rounds;i += 2) { QROUND(x[0], x[4], x[8], x[12]); QROUND(x[5], x[9], x[13], x[1]); QROUND(x[10], x[14], x[2], x[6]); QROUND(x[15], x[3], x[7], x[11]); QROUND(x[0], x[1], x[2], x[3]); QROUND(x[5], x[6], x[7], x[4]); QROUND(x[10], x[11], x[8], x[9]); QROUND(x[15], x[12], x[13], x[14]); } for (i = 0; i < SALSA20_INPUT_LENGTH; i++) { u32 t = x[i] + LE_SWAP32(src[i]); dst[i] = LE_SWAP32(t); } } static void scrypt_block_mix (u32 r, unsigned char *B, unsigned char *tmp2) { u64 i; unsigned char *X = tmp2; unsigned char *Y = tmp2 + 64; #if 0 if (r == 1) { for (i = 0; i < 2 * r; i++) { size_t j; printf ("B[%d] = ", (int)i); for (j = 0; j < 64; j++) { if (j && !(j % 16)) printf ("\n "); printf (" %02x", B[i * 64 + j]); } putchar ('\n'); } } #endif /* X = B[2 * r - 1] */ memcpy (X, &B[(2 * r - 1) * 64], 64); /* for i = 0 to 2 * r - 1 do */ for (i = 0; i <= 2 * r - 1; i++) { /* T = X xor B[i] */ buf_xor(X, X, &B[i * 64], 64); /* X = Salsa (T) */ salsa20_core ((u32*)(void*)X, (u32*)(void*)X, 8); /* Y[i] = X */ memcpy (&Y[i * 64], X, 64); } for (i = 0; i < r; i++) { memcpy (&B[i * 64], &Y[2 * i * 64], 64); memcpy (&B[(r + i) * 64], &Y[(2 * i + 1) * 64], 64); } #if 0 if (r==1) { for (i = 0; i < 2 * r; i++) { size_t j; printf ("B'[%d] =", (int)i); for (j = 0; j < 64; j++) { if (j && !(j % 16)) printf ("\n "); printf (" %02x", B[i * 64 + j]); } putchar ('\n'); } } #endif } static void scrypt_ro_mix (u32 r, unsigned char *B, u64 N, unsigned char *tmp1, unsigned char *tmp2) { unsigned char *X = B, *T = B; u64 i; #if 0 if (r == 1) { printf ("B = "); for (i = 0; i < 128 * r; i++) { if (i && !(i % 16)) printf ("\n "); printf (" %02x", B[i]); } putchar ('\n'); } #endif /* for i = 0 to N - 1 do */ for (i = 0; i <= N - 1; i++) { /* V[i] = X */ memcpy (&tmp1[i * 128 * r], X, 128 * r); /* X = ScryptBlockMix (X) */ scrypt_block_mix (r, X, tmp2); } /* for i = 0 to N - 1 do */ for (i = 0; i <= N - 1; i++) { u64 j; /* j = Integerify (X) mod N */ j = LE_READ_UINT64 (&X[128 * r - 64]) % N; /* T = X xor V[j] */ buf_xor (T, T, &tmp1[j * 128 * r], 128 * r); /* X = scryptBlockMix (T) */ scrypt_block_mix (r, T, tmp2); } #if 0 if (r == 1) { printf ("B' ="); for (i = 0; i < 128 * r; i++) { if (i && !(i % 16)) printf ("\n "); printf (" %02x", B[i]); } putchar ('\n'); } #endif } /* * */ gcry_err_code_t _gcry_kdf_scrypt (const unsigned char *passwd, size_t passwdlen, int algo, int subalgo, const unsigned char *salt, size_t saltlen, unsigned long iterations, size_t dkLen, unsigned char *DK) { u64 N = subalgo; /* CPU/memory cost parameter. */ u32 r; /* Block size. */ u32 p = iterations; /* Parallelization parameter. */ gpg_err_code_t ec; u32 i; unsigned char *B = NULL; unsigned char *tmp1 = NULL; unsigned char *tmp2 = NULL; size_t r128; size_t nbytes; if (subalgo < 1 || !iterations) return GPG_ERR_INV_VALUE; if (algo == GCRY_KDF_SCRYPT) r = 8; else if (algo == 41) /* Hack to allow the use of all test vectors. */ r = 1; else return GPG_ERR_UNKNOWN_ALGORITHM; r128 = r * 128; if (r128 / 128 != r) return GPG_ERR_ENOMEM; nbytes = p * r128; if (r128 && nbytes / r128 != p) return GPG_ERR_ENOMEM; nbytes = N * r128; if (r128 && nbytes / r128 != N) return GPG_ERR_ENOMEM; nbytes = 64 + r128; if (nbytes < r128) return GPG_ERR_ENOMEM; B = xtrymalloc (p * r128); if (!B) { ec = gpg_err_code_from_syserror (); goto leave; } tmp1 = xtrymalloc (N * r128); if (!tmp1) { ec = gpg_err_code_from_syserror (); goto leave; } tmp2 = xtrymalloc (64 + r128); if (!tmp2) { ec = gpg_err_code_from_syserror (); goto leave; } ec = _gcry_kdf_pkdf2 (passwd, passwdlen, GCRY_MD_SHA256, salt, saltlen, 1 /* iterations */, p * r128, B); for (i = 0; !ec && i < p; i++) scrypt_ro_mix (r, &B[i * r128], N, tmp1, tmp2); for (i = 0; !ec && i < p; i++) ec = _gcry_kdf_pkdf2 (passwd, passwdlen, GCRY_MD_SHA256, B, p * r128, 1 /* iterations */, dkLen, DK); leave: xfree (tmp2); xfree (tmp1); xfree (B); return ec; }