diff options
Diffstat (limited to 'src/secp256k1/include/secp256k1.h')
| -rw-r--r-- | src/secp256k1/include/secp256k1.h | 51 |
1 files changed, 41 insertions, 10 deletions
diff --git a/src/secp256k1/include/secp256k1.h b/src/secp256k1/include/secp256k1.h index dca7ca00e7..cfdae31eaf 100644 --- a/src/secp256k1/include/secp256k1.h +++ b/src/secp256k1/include/secp256k1.h @@ -77,42 +77,73 @@ SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify( int pubkeylen ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4); +/** A pointer to a function to deterministically generate a nonce. + * Returns: 1 if a nonce was succesfully generated. 0 will cause signing to fail. + * In: msg32: the 32-byte message hash being verified (will not be NULL) + * key32: pointer to a 32-byte secret key (will not be NULL) + * attempt: how many iterations we have tried to find a nonce. + * This will almost always be 0, but different attempt values + * are required to result in a different nonce. + * data: Arbitrary data pointer that is passed through. + * Out: nonce32: pointer to a 32-byte array to be filled by the function. + * Except for test cases, this function should compute some cryptographic hash of + * the message, the key and the attempt. + */ +typedef int (*secp256k1_nonce_function_t)( + unsigned char *nonce32, + const unsigned char *msg32, + const unsigned char *key32, + unsigned int attempt, + const void *data +); + +/** An implementation of RFC6979 (using HMAC-SHA256) as nonce generation function. */ +extern const secp256k1_nonce_function_t secp256k1_nonce_function_rfc6979; + +/** A default safe nonce generation function (currently equal to secp256k1_nonce_function_rfc6979). */ +extern const secp256k1_nonce_function_t secp256k1_nonce_function_default; + + /** Create an ECDSA signature. * Returns: 1: signature created - * 0: nonce invalid, try another one + * 0: the nonce generation function failed * In: msg32: the 32-byte message hash being signed (cannot be NULL) * seckey: pointer to a 32-byte secret key (cannot be NULL, assumed to be valid) - * nonce: pointer to a 32-byte nonce (cannot be NULL, generated with a cryptographic PRNG) + * noncefp:pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used + * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL) * Out: sig: pointer to an array where the signature will be placed (cannot be NULL) * In/Out: siglen: pointer to an int with the length of sig, which will be updated * to contain the actual signature length (<=72). * Requires starting using SECP256K1_START_SIGN. */ -SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_sign( +int secp256k1_ecdsa_sign( const unsigned char *msg32, unsigned char *sig, int *siglen, const unsigned char *seckey, - const unsigned char *nonce -) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5); + secp256k1_nonce_function_t noncefp, + const void *ndata +) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4); /** Create a compact ECDSA signature (64 byte + recovery id). * Returns: 1: signature created - * 0: nonce invalid, try another one + * 0: the nonce generation function failed * In: msg32: the 32-byte message hash being signed (cannot be NULL) * seckey: pointer to a 32-byte secret key (cannot be NULL, assumed to be valid) - * nonce: pointer to a 32-byte nonce (cannot be NULL, generated with a cryptographic PRNG) + * noncefp:pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used + * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL) * Out: sig: pointer to a 64-byte array where the signature will be placed (cannot be NULL) * recid: pointer to an int, which will be updated to contain the recovery id (can be NULL) * Requires starting using SECP256K1_START_SIGN. */ -SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_sign_compact( +int secp256k1_ecdsa_sign_compact( const unsigned char *msg32, unsigned char *sig64, const unsigned char *seckey, - const unsigned char *nonce, + secp256k1_nonce_function_t noncefp, + const void *ndata, int *recid -) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4); +) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); /** Recover an ECDSA public key from a compact signature. * Returns: 1: public key successfully recovered (which guarantees a correct signature). |