diff options
Diffstat (limited to 'libtomcrypt/src/pk/rsa/rsa_sign_hash.c')
| -rw-r--r-- | libtomcrypt/src/pk/rsa/rsa_sign_hash.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/libtomcrypt/src/pk/rsa/rsa_sign_hash.c b/libtomcrypt/src/pk/rsa/rsa_sign_hash.c new file mode 100644 index 0000000..f10a97a --- /dev/null +++ b/libtomcrypt/src/pk/rsa/rsa_sign_hash.c @@ -0,0 +1,134 @@ +/* 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://libtomcrypt.com + */ +#include "tomcrypt.h" + +/** + @file rsa_sign_hash.c + RSA PKCS #1 v1.5 and v2 PSS sign hash, Tom St Denis and Andreas Lange +*/ + +#ifdef MRSA + +/** + PKCS #1 pad then sign + @param in The hash to sign + @param inlen The length of the hash to sign (octets) + @param out [out] The signature + @param outlen [in/out] The max size and resulting size of the signature + @param padding Type of padding (LTC_PKCS_1_PSS or LTC_PKCS_1_V1_5) + @param prng An active PRNG state + @param prng_idx The index of the PRNG desired + @param hash_idx The index of the hash desired + @param saltlen The length of the salt desired (octets) + @param key The private RSA key to use + @return CRYPT_OK if successful +*/ +int rsa_sign_hash_ex(const unsigned char *in, unsigned long inlen, + unsigned char *out, unsigned long *outlen, + int padding, + prng_state *prng, int prng_idx, + int hash_idx, unsigned long saltlen, + rsa_key *key) +{ + unsigned long modulus_bitlen, modulus_bytelen, x, y; + int err; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + LTC_ARGCHK(key != NULL); + + /* valid padding? */ + if ((padding != LTC_PKCS_1_V1_5) && (padding != LTC_PKCS_1_PSS)) { + return CRYPT_PK_INVALID_PADDING; + } + + if (padding == LTC_PKCS_1_PSS) { + /* valid prng and hash ? */ + if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) { + return err; + } + 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 > *outlen) { + *outlen = modulus_bytelen; + return CRYPT_BUFFER_OVERFLOW; + } + + if (padding == LTC_PKCS_1_PSS) { + /* PSS pad the key */ + x = *outlen; + if ((err = pkcs_1_pss_encode(in, inlen, saltlen, prng, prng_idx, + hash_idx, modulus_bitlen, out, &x)) != CRYPT_OK) { + return err; + } + } else { + /* PKCS #1 v1.5 pad the hash */ + unsigned char *tmpin; + ltc_asn1_list digestinfo[2], siginfo[2]; + + /* not all hashes have OIDs... so sad */ + if (hash_descriptor[hash_idx].OIDlen == 0) { + return CRYPT_INVALID_ARG; + } + + /* construct the SEQUENCE + SEQUENCE { + SEQUENCE {hashoid OID + blah NULL + } + hash OCTET STRING + } + */ + LTC_SET_ASN1(digestinfo, 0, LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash_idx].OID, hash_descriptor[hash_idx].OIDlen); + LTC_SET_ASN1(digestinfo, 1, LTC_ASN1_NULL, NULL, 0); + LTC_SET_ASN1(siginfo, 0, LTC_ASN1_SEQUENCE, digestinfo, 2); + LTC_SET_ASN1(siginfo, 1, LTC_ASN1_OCTET_STRING, in, inlen); + + /* allocate memory for the encoding */ + y = mp_unsigned_bin_size(key->N); + tmpin = XMALLOC(y); + if (tmpin == NULL) { + return CRYPT_MEM; + } + + if ((err = der_encode_sequence(siginfo, 2, tmpin, &y)) != CRYPT_OK) { + XFREE(tmpin); + return err; + } + + x = *outlen; + if ((err = pkcs_1_v1_5_encode(tmpin, y, LTC_PKCS_1_EMSA, + modulus_bitlen, NULL, 0, + out, &x)) != CRYPT_OK) { + XFREE(tmpin); + return err; + } + XFREE(tmpin); + } + + /* RSA encode it */ + return ltc_mp.rsa_me(out, x, out, outlen, PK_PRIVATE, key); +} + +#endif /* MRSA */ + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_sign_hash.c,v $ */ +/* $Revision: 1.9 $ */ +/* $Date: 2006/11/09 23:15:39 $ */ |