mirror of https://github.com/bitcoin/bitcoin
250 lines
11 KiB
C
250 lines
11 KiB
C
#ifndef SECP256K1_EXTRAKEYS_H
|
|
#define SECP256K1_EXTRAKEYS_H
|
|
|
|
#include "secp256k1.h"
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
/** Opaque data structure that holds a parsed and valid "x-only" public key.
|
|
* An x-only pubkey encodes a point whose Y coordinate is even. It is
|
|
* serialized using only its X coordinate (32 bytes). See BIP-340 for more
|
|
* information about x-only pubkeys.
|
|
*
|
|
* 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, transmission, use
|
|
* use secp256k1_xonly_pubkey_serialize and secp256k1_xonly_pubkey_parse. To
|
|
* compare keys, use secp256k1_xonly_pubkey_cmp.
|
|
*/
|
|
typedef struct {
|
|
unsigned char data[64];
|
|
} secp256k1_xonly_pubkey;
|
|
|
|
/** Opaque data structure that holds a keypair consisting of a secret and a
|
|
* public key.
|
|
*
|
|
* 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 96 bytes in size, and can be safely copied/moved.
|
|
*/
|
|
typedef struct {
|
|
unsigned char data[96];
|
|
} secp256k1_keypair;
|
|
|
|
/** Parse a 32-byte sequence into a xonly_pubkey object.
|
|
*
|
|
* Returns: 1 if the public key was fully valid.
|
|
* 0 if the public key could not be parsed or is invalid.
|
|
*
|
|
* Args: ctx: a secp256k1 context object.
|
|
* Out: pubkey: pointer to a pubkey object. If 1 is returned, it is set to a
|
|
* parsed version of input. If not, it's set to an invalid value.
|
|
* In: input32: pointer to a serialized xonly_pubkey.
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_parse(
|
|
const secp256k1_context* ctx,
|
|
secp256k1_xonly_pubkey* pubkey,
|
|
const unsigned char *input32
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
|
|
|
|
/** Serialize an xonly_pubkey object into a 32-byte sequence.
|
|
*
|
|
* Returns: 1 always.
|
|
*
|
|
* Args: ctx: a secp256k1 context object.
|
|
* Out: output32: a pointer to a 32-byte array to place the serialized key in.
|
|
* In: pubkey: a pointer to a secp256k1_xonly_pubkey containing an initialized public key.
|
|
*/
|
|
SECP256K1_API int secp256k1_xonly_pubkey_serialize(
|
|
const secp256k1_context* ctx,
|
|
unsigned char *output32,
|
|
const secp256k1_xonly_pubkey* pubkey
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
|
|
|
|
/** Compare two x-only public keys using lexicographic order
|
|
*
|
|
* Returns: <0 if the first public key is less than the second
|
|
* >0 if the first public key is greater than the second
|
|
* 0 if the two public keys are equal
|
|
* Args: ctx: a secp256k1 context object.
|
|
* In: pubkey1: first public key to compare
|
|
* pubkey2: second public key to compare
|
|
*/
|
|
SECP256K1_API int secp256k1_xonly_pubkey_cmp(
|
|
const secp256k1_context* ctx,
|
|
const secp256k1_xonly_pubkey* pk1,
|
|
const secp256k1_xonly_pubkey* pk2
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
|
|
|
|
/** Converts a secp256k1_pubkey into a secp256k1_xonly_pubkey.
|
|
*
|
|
* Returns: 1 always.
|
|
*
|
|
* Args: ctx: pointer to a context object.
|
|
* Out: xonly_pubkey: pointer to an x-only public key object for placing the converted public key.
|
|
* pk_parity: Ignored if NULL. Otherwise, pointer to an integer that
|
|
* will be set to 1 if the point encoded by xonly_pubkey is
|
|
* the negation of the pubkey and set to 0 otherwise.
|
|
* In: pubkey: pointer to a public key that is converted.
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_from_pubkey(
|
|
const secp256k1_context* ctx,
|
|
secp256k1_xonly_pubkey *xonly_pubkey,
|
|
int *pk_parity,
|
|
const secp256k1_pubkey *pubkey
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
|
|
|
|
/** Tweak an x-only public key by adding the generator multiplied with tweak32
|
|
* to it.
|
|
*
|
|
* Note that the resulting point can not in general be represented by an x-only
|
|
* pubkey because it may have an odd Y coordinate. Instead, the output_pubkey
|
|
* is a normal secp256k1_pubkey.
|
|
*
|
|
* Returns: 0 if the arguments are invalid or the resulting public key would be
|
|
* invalid (only when the tweak is the negation of the corresponding
|
|
* secret key). 1 otherwise.
|
|
*
|
|
* Args: ctx: pointer to a context object.
|
|
* Out: output_pubkey: pointer to a public key to store the result. Will be set
|
|
* to an invalid value if this function returns 0.
|
|
* In: internal_pubkey: pointer to an x-only pubkey to apply the tweak to.
|
|
* tweak32: pointer to a 32-byte tweak. If the tweak is invalid
|
|
* according to secp256k1_ec_seckey_verify, this function
|
|
* returns 0. For uniformly random 32-byte arrays the
|
|
* chance of being invalid is negligible (around 1 in 2^128).
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_tweak_add(
|
|
const secp256k1_context* ctx,
|
|
secp256k1_pubkey *output_pubkey,
|
|
const secp256k1_xonly_pubkey *internal_pubkey,
|
|
const unsigned char *tweak32
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
|
|
|
|
/** Checks that a tweaked pubkey is the result of calling
|
|
* secp256k1_xonly_pubkey_tweak_add with internal_pubkey and tweak32.
|
|
*
|
|
* The tweaked pubkey is represented by its 32-byte x-only serialization and
|
|
* its pk_parity, which can both be obtained by converting the result of
|
|
* tweak_add to a secp256k1_xonly_pubkey.
|
|
*
|
|
* Note that this alone does _not_ verify that the tweaked pubkey is a
|
|
* commitment. If the tweak is not chosen in a specific way, the tweaked pubkey
|
|
* can easily be the result of a different internal_pubkey and tweak.
|
|
*
|
|
* Returns: 0 if the arguments are invalid or the tweaked pubkey is not the
|
|
* result of tweaking the internal_pubkey with tweak32. 1 otherwise.
|
|
* Args: ctx: pointer to a context object.
|
|
* In: tweaked_pubkey32: pointer to a serialized xonly_pubkey.
|
|
* tweaked_pk_parity: the parity of the tweaked pubkey (whose serialization
|
|
* is passed in as tweaked_pubkey32). This must match the
|
|
* pk_parity value that is returned when calling
|
|
* secp256k1_xonly_pubkey with the tweaked pubkey, or
|
|
* this function will fail.
|
|
* internal_pubkey: pointer to an x-only public key object to apply the tweak to.
|
|
* tweak32: pointer to a 32-byte tweak.
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_tweak_add_check(
|
|
const secp256k1_context* ctx,
|
|
const unsigned char *tweaked_pubkey32,
|
|
int tweaked_pk_parity,
|
|
const secp256k1_xonly_pubkey *internal_pubkey,
|
|
const unsigned char *tweak32
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5);
|
|
|
|
/** Compute the keypair for a secret key.
|
|
*
|
|
* Returns: 1: secret was valid, keypair is ready to use
|
|
* 0: secret was invalid, try again with a different secret
|
|
* Args: ctx: pointer to a context object (not secp256k1_context_static).
|
|
* Out: keypair: pointer to the created keypair.
|
|
* In: seckey: pointer to a 32-byte secret key.
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_create(
|
|
const secp256k1_context* ctx,
|
|
secp256k1_keypair *keypair,
|
|
const unsigned char *seckey
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
|
|
|
|
/** Get the secret key from a keypair.
|
|
*
|
|
* Returns: 1 always.
|
|
* Args: ctx: pointer to a context object.
|
|
* Out: seckey: pointer to a 32-byte buffer for the secret key.
|
|
* In: keypair: pointer to a keypair.
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_sec(
|
|
const secp256k1_context* ctx,
|
|
unsigned char *seckey,
|
|
const secp256k1_keypair *keypair
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
|
|
|
|
/** Get the public key from a keypair.
|
|
*
|
|
* Returns: 1 always.
|
|
* Args: ctx: pointer to a context object.
|
|
* Out: pubkey: pointer to a pubkey object. If 1 is returned, it is set to
|
|
* the keypair public key. If not, it's set to an invalid value.
|
|
* In: keypair: pointer to a keypair.
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_pub(
|
|
const secp256k1_context* ctx,
|
|
secp256k1_pubkey *pubkey,
|
|
const secp256k1_keypair *keypair
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
|
|
|
|
/** Get the x-only public key from a keypair.
|
|
*
|
|
* This is the same as calling secp256k1_keypair_pub and then
|
|
* secp256k1_xonly_pubkey_from_pubkey.
|
|
*
|
|
* Returns: 1 always.
|
|
* Args: ctx: pointer to a context object.
|
|
* Out: pubkey: pointer to an xonly_pubkey object. If 1 is returned, it is set
|
|
* to the keypair public key after converting it to an
|
|
* xonly_pubkey. If not, it's set to an invalid value.
|
|
* pk_parity: Ignored if NULL. Otherwise, pointer to an integer that will be set to the
|
|
* pk_parity argument of secp256k1_xonly_pubkey_from_pubkey.
|
|
* In: keypair: pointer to a keypair.
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_xonly_pub(
|
|
const secp256k1_context* ctx,
|
|
secp256k1_xonly_pubkey *pubkey,
|
|
int *pk_parity,
|
|
const secp256k1_keypair *keypair
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
|
|
|
|
/** Tweak a keypair by adding tweak32 to the secret key and updating the public
|
|
* key accordingly.
|
|
*
|
|
* Calling this function and then secp256k1_keypair_pub results in the same
|
|
* public key as calling secp256k1_keypair_xonly_pub and then
|
|
* secp256k1_xonly_pubkey_tweak_add.
|
|
*
|
|
* Returns: 0 if the arguments are invalid or the resulting keypair would be
|
|
* invalid (only when the tweak is the negation of the keypair's
|
|
* secret key). 1 otherwise.
|
|
*
|
|
* Args: ctx: pointer to a context object.
|
|
* In/Out: keypair: pointer to a keypair to apply the tweak to. Will be set to
|
|
* an invalid value if this function returns 0.
|
|
* In: tweak32: pointer to a 32-byte tweak. If the tweak is invalid according
|
|
* to secp256k1_ec_seckey_verify, this function returns 0. For
|
|
* uniformly random 32-byte arrays the chance of being invalid
|
|
* is negligible (around 1 in 2^128).
|
|
*/
|
|
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_xonly_tweak_add(
|
|
const secp256k1_context* ctx,
|
|
secp256k1_keypair *keypair,
|
|
const unsigned char *tweak32
|
|
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* SECP256K1_EXTRAKEYS_H */
|