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#ifndef SECP256K1_RECOVERY_H
#define SECP256K1_RECOVERY_H
#include "secp256k1.h"
#ifdef __cplusplus
extern "C" {
#endif
/** Opaque data structure that holds a parsed ECDSA signature,
* supporting pubkey recovery.
*
* 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 65 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_parse_* functions.
*
* Furthermore, it is guaranteed that identical signatures (including their
* recoverability) will have identical representation, so they can be
* memcmp'ed.
*/
typedef struct secp256k1_ecdsa_recoverable_signature {
unsigned char data[65];
} secp256k1_ecdsa_recoverable_signature;
/** Parse a compact ECDSA signature (64 bytes + recovery id).
*
* Returns: 1 when the signature could be parsed, 0 otherwise
* Args: ctx: pointer to a context object
* Out: sig: pointer to a signature object
* In: input64: pointer to a 64-byte compact signature
* recid: the recovery id (0, 1, 2 or 3)
*/
SECP256K1_API int secp256k1_ecdsa_recoverable_signature_parse_compact(
const secp256k1_context *ctx,
secp256k1_ecdsa_recoverable_signature *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
* Args: ctx: pointer to a context object.
* Out: sig: pointer to a normal signature.
* In: sigin: pointer to a recoverable signature.
*/
SECP256K1_API int secp256k1_ecdsa_recoverable_signature_convert(
const secp256k1_context *ctx,
secp256k1_ecdsa_signature *sig,
const secp256k1_ecdsa_recoverable_signature *sigin
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Serialize an ECDSA signature in compact format (64 bytes + recovery id).
*
* Returns: 1
* Args: ctx: pointer to a context object.
* Out: output64: pointer to a 64-byte array of the compact signature.
* recid: pointer to an integer to hold the recovery id.
* In: sig: pointer to an initialized signature object.
*/
SECP256K1_API int secp256k1_ecdsa_recoverable_signature_serialize_compact(
const secp256k1_context *ctx,
unsigned char *output64,
int *recid,
const secp256k1_ecdsa_recoverable_signature *sig
) 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 secret key was invalid.
* Args: ctx: pointer to a context object (not secp256k1_context_static).
* Out: sig: pointer to an array where the signature will be placed.
* In: msghash32: the 32-byte message hash being signed.
* seckey: pointer to a 32-byte secret key.
* 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 for secp256k1_nonce_function_default).
*/
SECP256K1_API int secp256k1_ecdsa_sign_recoverable(
const secp256k1_context *ctx,
secp256k1_ecdsa_recoverable_signature *sig,
const unsigned char *msghash32,
const unsigned char *seckey,
secp256k1_nonce_function 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).
* 0: otherwise.
* Args: ctx: pointer to a context object.
* Out: pubkey: pointer to the recovered public key.
* In: sig: pointer to initialized signature that supports pubkey recovery.
* msghash32: the 32-byte message hash assumed to be signed.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_recover(
const secp256k1_context *ctx,
secp256k1_pubkey *pubkey,
const secp256k1_ecdsa_recoverable_signature *sig,
const unsigned char *msghash32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
#ifdef __cplusplus
}
#endif
#endif /* SECP256K1_RECOVERY_H */
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