Mercurial > dropbear
view src/pk/rsa/rsa_verify_hash.c @ 222:36160290a1b2 libtomcrypt LTC_DB_0.46
* change include path of options.h
* don't use the constant ROL/ROR operations, since compilers
seem to have problems
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Fri, 08 Jul 2005 19:13:24 +0000 |
parents | 39d5d58461d6 |
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 "tomcrypt.h" /** @file rsa_verify_hash.c RSA PKCS v2 PSS signature verification, Tom St Denis */ #ifdef MRSA /** (PKCS #1, v2.0) de-sign then PSS depad @param sig The signature data @param siglen The length of the signature data (octets) @param hash The hash of the message that was signed @param hashlen The length of the hash of the message that was signed (octets) @param hash_idx The index of the desired hash @param saltlen The length of the salt used during signature @param stat [out] The result of the signature comparison, 1==valid, 0==invalid @param key The public RSA key corresponding to the key that performed the signature @return CRYPT_OK on success (even if the signature is invalid) */ int rsa_verify_hash(const unsigned char *sig, unsigned long siglen, const unsigned char *hash, unsigned long hashlen, int hash_idx, unsigned long saltlen, int *stat, rsa_key *key) { unsigned long modulus_bitlen, modulus_bytelen, x; int err; unsigned char *tmpbuf; LTC_ARGCHK(hash != NULL); LTC_ARGCHK(sig != NULL); LTC_ARGCHK(stat != NULL); LTC_ARGCHK(key != NULL); /* default to invalid */ *stat = 0; /* valid hash ? */ if ((err = hash_is_valid(hash_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, key)) != CRYPT_OK) { XFREE(tmpbuf); return err; } /* PSS decode it */ err = pkcs_1_pss_decode(hash, hashlen, tmpbuf, x, saltlen, hash_idx, modulus_bitlen, stat); XFREE(tmpbuf); return err; } #endif /* MRSA */ /* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_verify_hash.c,v $ */ /* $Revision: 1.3 $ */ /* $Date: 2005/05/05 14:35:59 $ */