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Change rfc6979 implementation to be a generic PRNG

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This commit is contained in:
Pieter Wuille
2015-07-08 18:10:25 -04:00
parent 1b68366201
commit 3e6f1e20dc
7 changed files with 30 additions and 25 deletions
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13
src/secp256k1.c
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@@ -86,9 +86,20 @@ int secp256k1_ecdsa_verify(const secp256k1_context_t* ctx, const unsigned char *
}
static int nonce_function_rfc6979(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, unsigned int counter, const void *data) {
unsigned char keydata[96];
secp256k1_rfc6979_hmac_sha256_t rng;
unsigned int i;
secp256k1_rfc6979_hmac_sha256_initialize(&rng, key32, 32, msg32, 32, (const unsigned char*)data, data != NULL ? 32 : 0);
/* We feed a byte array to the PRNG as input, consisting of:
* - the private key (32 bytes) and message (32 bytes), see RFC 6979 3.2d.
* - optionally 32 extra bytes of data, see RFC 6979 3.6 Additional Data.
*/
memcpy(keydata, key32, 32);
memcpy(keydata + 32, msg32, 32);
if (data != NULL) {
memcpy(keydata + 64, data, 32);
}
secp256k1_rfc6979_hmac_sha256_initialize(&rng, keydata, data != NULL ? 96 : 64);
memset(keydata, 0, sizeof(keydata));
for (i = 0; i <= counter; i++) {
secp256k1_rfc6979_hmac_sha256_generate(&rng, nonce32, 32);
}