diff options
Diffstat (limited to 'libtomcrypt/src/pk/ecc/ecc_sign_hash.c')
| -rw-r--r-- | libtomcrypt/src/pk/ecc/ecc_sign_hash.c | 114 |
1 files changed, 84 insertions, 30 deletions
diff --git a/libtomcrypt/src/pk/ecc/ecc_sign_hash.c b/libtomcrypt/src/pk/ecc/ecc_sign_hash.c index 0ef7e2b..bae0c00 100644 --- a/libtomcrypt/src/pk/ecc/ecc_sign_hash.c +++ b/libtomcrypt/src/pk/ecc/ecc_sign_hash.c @@ -5,42 +5,26 @@ * * The library is free for all purposes without any express * guarantee it works. - * - * Tom St Denis, tomstdenis@gmail.com, http://libtom.org */ -/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b - * - * All curves taken from NIST recommendation paper of July 1999 - * Available at http://csrc.nist.gov/cryptval/dss.htm - */ #include "tomcrypt.h" +#ifdef LTC_MECC + /** @file ecc_sign_hash.c ECC Crypto, Tom St Denis */ -#if defined(LTC_MECC) && defined(LTC_DER) - -/** - Sign a message digest - @param in The message digest to sign - @param inlen The length of the digest - @param out [out] The destination for 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 you wish to use - @param key A private ECC key - @return CRYPT_OK if successful -*/ -int ecc_sign_hash(const unsigned char *in, unsigned long inlen, +static int _ecc_sign_hash(const unsigned char *in, unsigned long inlen, unsigned char *out, unsigned long *outlen, - prng_state *prng, int wprng, ecc_key *key) + prng_state *prng, int wprng, ecc_key *key, int sigformat) { ecc_key pubkey; void *r, *s, *e, *p; - int err; + int err, max_iterations = LTC_PK_MAX_RETRIES; + unsigned long pbits, pbytes, i, shift_right; + unsigned char ch, buf[MAXBLOCKSIZE]; LTC_ARGCHK(in != NULL); LTC_ARGCHK(out != NULL); @@ -61,16 +45,33 @@ int ecc_sign_hash(const unsigned char *in, unsigned long inlen, return err; } - /* get the hash and load it as a bignum into 'e' */ /* init the bignums */ if ((err = mp_init_multi(&r, &s, &p, &e, NULL)) != CRYPT_OK) { return err; } if ((err = mp_read_radix(p, (char *)key->dp->order, 16)) != CRYPT_OK) { goto errnokey; } - if ((err = mp_read_unsigned_bin(e, (unsigned char *)in, (int)inlen)) != CRYPT_OK) { goto errnokey; } + + /* get the hash and load it as a bignum into 'e' */ + pbits = mp_count_bits(p); + pbytes = (pbits+7) >> 3; + if (pbits > inlen*8) { + if ((err = mp_read_unsigned_bin(e, (unsigned char *)in, inlen)) != CRYPT_OK) { goto errnokey; } + } + else if (pbits % 8 == 0) { + if ((err = mp_read_unsigned_bin(e, (unsigned char *)in, pbytes)) != CRYPT_OK) { goto errnokey; } + } + else { + shift_right = 8 - pbits % 8; + for (i=0, ch=0; i<pbytes; i++) { + buf[i] = ch; + ch = (in[i] << (8-shift_right)); + buf[i] = buf[i] ^ (in[i] >> shift_right); + } + if ((err = mp_read_unsigned_bin(e, (unsigned char *)buf, pbytes)) != CRYPT_OK) { goto errnokey; } + } /* make up a key and export the public copy */ - for (;;) { + do { if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) { goto errnokey; } @@ -92,13 +93,30 @@ int ecc_sign_hash(const unsigned char *in, unsigned long inlen, break; } } + } while (--max_iterations > 0); + + if (max_iterations == 0) { + goto errnokey; } - /* store as SEQUENCE { r, s -- integer } */ + if (sigformat == 1) { + /* RFC7518 format */ + if (*outlen < 2*pbytes) { err = CRYPT_MEM; goto errnokey; } + zeromem(out, 2*pbytes); + i = mp_unsigned_bin_size(r); + if ((err = mp_to_unsigned_bin(r, out + (pbytes - i))) != CRYPT_OK) { goto errnokey; } + i = mp_unsigned_bin_size(s); + if ((err = mp_to_unsigned_bin(s, out + (2*pbytes - i))) != CRYPT_OK) { goto errnokey; } + *outlen = 2*pbytes; + err = CRYPT_OK; + } + else { + /* store as ASN.1 SEQUENCE { r, s -- integer } */ err = der_encode_sequence_multi(out, outlen, LTC_ASN1_INTEGER, 1UL, r, LTC_ASN1_INTEGER, 1UL, s, LTC_ASN1_EOL, 0UL, NULL); + } goto errnokey; error: ecc_free(&pubkey); @@ -107,8 +125,44 @@ errnokey: return err; } +/** + Sign a message digest + @param in The message digest to sign + @param inlen The length of the digest + @param out [out] The destination for 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 you wish to use + @param key A private ECC key + @return CRYPT_OK if successful +*/ +int ecc_sign_hash(const unsigned char *in, unsigned long inlen, + unsigned char *out, unsigned long *outlen, + prng_state *prng, int wprng, ecc_key *key) +{ + return _ecc_sign_hash(in, inlen, out, outlen, prng, wprng, key, 0); +} + +/** + Sign a message digest in RFC7518 format + @param in The message digest to sign + @param inlen The length of the digest + @param out [out] The destination for 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 you wish to use + @param key A private ECC key + @return CRYPT_OK if successful +*/ +int ecc_sign_hash_rfc7518(const unsigned char *in, unsigned long inlen, + unsigned char *out, unsigned long *outlen, + prng_state *prng, int wprng, ecc_key *key) +{ + return _ecc_sign_hash(in, inlen, out, outlen, prng, wprng, key, 1); +} + #endif -/* $Source$ */ -/* $Revision$ */ -/* $Date$ */ +/* ref: $Format:%D$ */ +/* git commit: $Format:%H$ */ +/* commit time: $Format:%ai$ */ |