Mercurial > dropbear
view rsa_verify_hash.c @ 164:cd1143579f00 libtomcrypt LTC_DB_0.44
mpi.c isn't needed if we're using libtommath seperately
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sun, 02 Jan 2005 17:19:46 +0000 |
parents | 5d99163f7e32 |
children |
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/* 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, [email protected], http://libtomcrypt.org */ #include "mycrypt.h" #ifdef MRSA /* (PKCS #1, v2.0) de-sign then PSS depad */ int rsa_verify_hash(const unsigned char *sig, unsigned long siglen, const unsigned char *msghash, unsigned long msghashlen, prng_state *prng, int prng_idx, int hash_idx, unsigned long saltlen, int *stat, rsa_key *key) { unsigned long modulus_bitlen, modulus_bytelen, x; int err; unsigned char *tmpbuf; _ARGCHK(msghash != NULL); _ARGCHK(sig != NULL); _ARGCHK(stat != NULL); _ARGCHK(key != NULL); /* default to invalid */ *stat = 0; /* valid hash ? */ if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { return err; } if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) { return err; } /* get modulus len in bits */ modulus_bitlen = mp_count_bits(&(key->N)); /* outlen must be at least the size of the modulus */ modulus_bytelen = mp_unsigned_bin_size(&(key->N)); if (modulus_bytelen != siglen) { return CRYPT_INVALID_PACKET; } /* allocate temp buffer for decoded sig */ tmpbuf = XMALLOC(siglen); if (tmpbuf == NULL) { return CRYPT_MEM; } /* RSA decode it */ x = siglen; if ((err = rsa_exptmod(sig, siglen, tmpbuf, &x, PK_PUBLIC, prng, prng_idx, key)) != CRYPT_OK) { XFREE(tmpbuf); return err; } /* PSS decode it */ err = pkcs_1_pss_decode(msghash, msghashlen, tmpbuf, x, saltlen, hash_idx, modulus_bitlen, stat); XFREE(tmpbuf); return err; } #endif /* MRSA */