diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/pk/dsa/dsa_sign_hash.c')
| -rw-r--r-- | core/lib/libtomcrypt/src/pk/dsa/dsa_sign_hash.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/pk/dsa/dsa_sign_hash.c b/core/lib/libtomcrypt/src/pk/dsa/dsa_sign_hash.c new file mode 100644 index 0000000..0c89967 --- /dev/null +++ b/core/lib/libtomcrypt/src/pk/dsa/dsa_sign_hash.c @@ -0,0 +1,178 @@ +/* + * Copyright (c) 2001-2007, Tom St Denis + * 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. + */ + +/* LibTomCrypt, modular cryptographic library -- Tom St Denis + * + * LibTomCrypt is a library that provides various cryptographic + * algorithms in a highly modular and flexible manner. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, tomstdenis@gmail.com, http://libtom.org + */ +#include "tomcrypt.h" + +/** + @file dsa_sign_hash.c + DSA implementation, sign a hash, Tom St Denis +*/ + +#ifdef LTC_MDSA + +/** + Sign a hash with DSA + @param in The hash to sign + @param inlen The length of the hash to sign + @param r The "r" integer of the signature (caller must initialize with mp_init() first) + @param s The "s" integer of the signature (caller must initialize with mp_init() first) + @param prng An active PRNG state + @param wprng The index of the PRNG desired + @param key A private DSA key + @return CRYPT_OK if successful +*/ +int dsa_sign_hash_raw(const unsigned char *in, unsigned long inlen, + void *r, void *s, + prng_state *prng, int wprng, dsa_key *key) +{ + void *k, *kinv, *tmp; + unsigned char *buf; + int err, qbits; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(r != NULL); + LTC_ARGCHK(s != NULL); + LTC_ARGCHK(key != NULL); + + if ((err = prng_is_valid(wprng)) != CRYPT_OK) { + return err; + } + if (key->type != PK_PRIVATE) { + return CRYPT_PK_NOT_PRIVATE; + } + + /* check group order size */ + if (key->qord >= LTC_MDSA_MAX_GROUP) { + return CRYPT_INVALID_ARG; + } + + buf = XMALLOC(LTC_MDSA_MAX_GROUP); + if (buf == NULL) { + return CRYPT_MEM; + } + + /* Init our temps */ + if ((err = mp_init_multi(&k, &kinv, &tmp, NULL)) != CRYPT_OK) { goto ERRBUF; } + + qbits = mp_count_bits(key->q); +retry: + + do { + /* gen random k */ + if ((err = rand_bn_bits(k, qbits, prng, wprng)) != CRYPT_OK) { goto error; } + + /* k should be from range: 1 <= k <= q-1 (see FIPS 186-4 B.2.2) */ + if (mp_cmp_d(k, 0) != LTC_MP_GT || mp_cmp(k, key->q) != LTC_MP_LT) { goto retry; } + + /* test gcd */ + if ((err = mp_gcd(k, key->q, tmp)) != CRYPT_OK) { goto error; } + } while (mp_cmp_d(tmp, 1) != LTC_MP_EQ); + + /* now find 1/k mod q */ + if ((err = mp_invmod(k, key->q, kinv)) != CRYPT_OK) { goto error; } + + /* now find r = g^k mod p mod q */ + if ((err = mp_exptmod(key->g, k, key->p, r)) != CRYPT_OK) { goto error; } + if ((err = mp_mod(r, key->q, r)) != CRYPT_OK) { goto error; } + + if (mp_iszero(r) == LTC_MP_YES) { goto retry; } + + /* now find s = (in + xr)/k mod q */ + if ((err = mp_read_unsigned_bin(tmp, (unsigned char *)in, inlen)) != CRYPT_OK) { goto error; } + if ((err = mp_mul(key->x, r, s)) != CRYPT_OK) { goto error; } + if ((err = mp_add(s, tmp, s)) != CRYPT_OK) { goto error; } + if ((err = mp_mulmod(s, kinv, key->q, s)) != CRYPT_OK) { goto error; } + + if (mp_iszero(s) == LTC_MP_YES) { goto retry; } + + err = CRYPT_OK; +error: + mp_clear_multi(k, kinv, tmp, NULL); +ERRBUF: +#ifdef LTC_CLEAN_STACK + zeromem(buf, LTC_MDSA_MAX_GROUP); +#endif + XFREE(buf); + return err; +} + +/** + Sign a hash with DSA + @param in The hash to sign + @param inlen The length of the hash to sign + @param out [out] Where to store the signature + @param outlen [in/out] The max size and resulting size of the signature + @param prng An active PRNG state + @param wprng The index of the PRNG desired + @param key A private DSA key + @return CRYPT_OK if successful +*/ +int dsa_sign_hash(const unsigned char *in, unsigned long inlen, + unsigned char *out, unsigned long *outlen, + prng_state *prng, int wprng, dsa_key *key) +{ + void *r, *s; + int err; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + LTC_ARGCHK(key != NULL); + + if (mp_init_multi(&r, &s, NULL) != CRYPT_OK) { + return CRYPT_MEM; + } + + if ((err = dsa_sign_hash_raw(in, inlen, r, s, prng, wprng, key)) != CRYPT_OK) { + goto error; + } + + err = der_encode_sequence_multi(out, outlen, + LTC_ASN1_INTEGER, 1UL, r, + LTC_ASN1_INTEGER, 1UL, s, + LTC_ASN1_EOL, 0UL, NULL); + +error: + mp_clear_multi(r, s, NULL); + return err; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_sign_hash.c,v $ */ +/* $Revision: 1.14 $ */ +/* $Date: 2007/05/12 14:32:35 $ */ |