diff options
Diffstat (limited to 'src/secp256k1/include/secp256k1_ecdh.h')
| -rw-r--r-- | src/secp256k1/include/secp256k1_ecdh.h | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/src/secp256k1/include/secp256k1_ecdh.h b/src/secp256k1/include/secp256k1_ecdh.h index 88492dc1a4..df5fde235c 100644 --- a/src/secp256k1/include/secp256k1_ecdh.h +++ b/src/secp256k1/include/secp256k1_ecdh.h @@ -7,21 +7,45 @@ extern "C" { #endif +/** A pointer to a function that applies hash function to a point + * + * Returns: 1 if a point was successfully hashed. 0 will cause ecdh to fail + * Out: output: pointer to an array to be filled by the function + * In: x: pointer to a 32-byte x coordinate + * y: pointer to a 32-byte y coordinate + * data: Arbitrary data pointer that is passed through + */ +typedef int (*secp256k1_ecdh_hash_function)( + unsigned char *output, + const unsigned char *x, + const unsigned char *y, + void *data +); + +/** An implementation of SHA256 hash function that applies to compressed public key. */ +SECP256K1_API extern const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_sha256; + +/** A default ecdh hash function (currently equal to secp256k1_ecdh_hash_function_sha256). */ +SECP256K1_API extern const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_default; + /** Compute an EC Diffie-Hellman secret in constant time * Returns: 1: exponentiation was successful * 0: scalar was invalid (zero or overflow) * Args: ctx: pointer to a context object (cannot be NULL) - * Out: result: a 32-byte array which will be populated by an ECDH - * secret computed from the point and scalar + * Out: output: pointer to an array to be filled by the function * In: pubkey: a pointer to a secp256k1_pubkey containing an * initialized public key * privkey: a 32-byte scalar with which to multiply the point + * hashfp: pointer to a hash function. If NULL, secp256k1_ecdh_hash_function_sha256 is used + * data: Arbitrary data pointer that is passed through */ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdh( const secp256k1_context* ctx, - unsigned char *result, + unsigned char *output, const secp256k1_pubkey *pubkey, - const unsigned char *privkey + const unsigned char *privkey, + secp256k1_ecdh_hash_function hashfp, + void *data ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4); #ifdef __cplusplus |