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Separate recoverable and normal signatures

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This commit is contained in:
Pieter Wuille
2015-08-27 03:09:23 +02:00
parent a7b046e554
commit 439d34adc6
5 changed files with 203 additions and 73 deletions
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71
include/secp256k1.h
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@@ -40,7 +40,23 @@ typedef struct {
unsigned char data[64];
} secp256k1_pubkey_t;
/** Opaque data structured that holds a parsed ECDSA signature, optionally
/** Opaque data structured that holds a parsed ECDSA signature.
*
* The exact representation of data inside is implementation defined and not
* guaranteed to be portable between different platforms or versions. It is
* however guaranteed to be 64 bytes in size, and can be safely copied/moved.
* If you need to convert to a format suitable for storage or transmission, use
* the secp256k1_ecdsa_signature_serialize_* and
* secp256k1_ecdsa_signature_serialize_* functions.
*
* Furthermore, it is guaranteed to identical signatures will have identical
* representation, so they can be memcmp'ed.
*/
typedef struct {
unsigned char data[64];
} secp256k1_ecdsa_signature_t;
/** Opaque data structured that holds a parsed ECDSA signature,
* supporting pubkey recovery.
*
* The exact representation of data inside is implementation defined and not
@@ -56,7 +72,7 @@ typedef struct {
*/
typedef struct {
unsigned char data[65];
} secp256k1_ecdsa_signature_t;
} secp256k1_ecdsa_recoverable_signature_t;
/** A pointer to a function to deterministically generate a nonce.
*
@@ -246,8 +262,6 @@ int secp256k1_ec_pubkey_serialize(
* Out: sig: a pointer to a signature object
*
* Note that this function also supports some violations of DER and even BER.
*
* The resulting signature object will not support pubkey recovery.
*/
int secp256k1_ecdsa_signature_parse_der(
const secp256k1_context_t* ctx,
@@ -261,19 +275,28 @@ int secp256k1_ecdsa_signature_parse_der(
* Returns: 1 when the signature could be parsed, 0 otherwise
* In: ctx: a secp256k1 context object
* input64: a pointer to a 64-byte compact signature
* recid: the recovery id (0, 1, 2 or 3, or -1 for unknown)
* recid: the recovery id (0, 1, 2 or 3)
* Out: sig: a pointer to a signature object
*
* If recid is not -1, the resulting signature object will support pubkey
* recovery.
*/
int secp256k1_ecdsa_signature_parse_compact(
int secp256k1_ecdsa_recoverable_signature_parse_compact(
const secp256k1_context_t* ctx,
secp256k1_ecdsa_signature_t* sig,
secp256k1_ecdsa_recoverable_signature_t* sig,
const unsigned char *input64,
int recid
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Convert a recoverable signature into a normal signature.
*
* Returns: 1
* In: sigin: a pointer to a recoverable signature (cannot be NULL).
* Out: sig: a pointer to a normal signature (cannot be NULL).
*/
int secp256k1_ecdsa_recoverable_signature_convert(
const secp256k1_context_t* ctx,
secp256k1_ecdsa_signature_t* sig,
const secp256k1_ecdsa_recoverable_signature_t* sigin
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Serialize an ECDSA signature in DER format.
*
* Returns: 1 if enough space was available to serialize, 0 otherwise
@@ -299,14 +322,12 @@ int secp256k1_ecdsa_signature_serialize_der(
* sig: a pointer to an initialized signature object (cannot be NULL)
* Out: output64: a pointer to a 64-byte array of the compact signature (cannot be NULL)
* recid: a pointer to an integer to hold the recovery id (can be NULL).
*
* If recid is not NULL, the signature must support pubkey recovery.
*/
int secp256k1_ecdsa_signature_serialize_compact(
int secp256k1_ecdsa_recoverable_signature_serialize_compact(
const secp256k1_context_t* ctx,
unsigned char *output64,
int *recid,
const secp256k1_ecdsa_signature_t* sig
const secp256k1_ecdsa_recoverable_signature_t* sig
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
/** Verify an ECDSA signature.
@@ -383,6 +404,26 @@ int secp256k1_ecdsa_sign(
const void *ndata
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
/** Create a recoverable ECDSA signature.
*
* Returns: 1: signature created
* 0: the nonce generation function failed, or the private key was invalid.
* In: ctx: pointer to a context object, initialized for signing (cannot be NULL)
* msg32: the 32-byte message hash being signed (cannot be NULL)
* seckey: pointer to a 32-byte secret key (cannot be NULL)
* 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)
*/
int secp256k1_ecdsa_sign_recoverable(
const secp256k1_context_t* ctx,
const unsigned char *msg32,
secp256k1_ecdsa_recoverable_signature_t *sig,
const unsigned char *seckey,
secp256k1_nonce_function_t noncefp,
const void *ndata
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
/** Recover an ECDSA public key from a signature.
*
* Returns: 1: public key successfully recovered (which guarantees a correct signature).
@@ -395,7 +436,7 @@ int secp256k1_ecdsa_sign(
SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_recover(
const secp256k1_context_t* ctx,
const unsigned char *msg32,
const secp256k1_ecdsa_signature_t *sig,
const secp256k1_ecdsa_recoverable_signature_t *sig,
secp256k1_pubkey_t *pubkey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);