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- #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, or
- * comparison, use secp256k1_xonly_pubkey_serialize and
- * secp256k1_xonly_pubkey_parse.
- */
- 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 (cannot be NULL).
- * 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.
- * (cannot be NULL).
- * In: input32: pointer to a serialized xonly_pubkey (cannot be NULL)
- */
- 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 (cannot be NULL).
- * Out: output32: a pointer to a 32-byte array to place the serialized key in
- * (cannot be NULL).
- * In: pubkey: a pointer to a secp256k1_xonly_pubkey containing an
- * initialized public key (cannot be NULL).
- */
- 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);
-
- /** Converts a secp256k1_pubkey into a secp256k1_xonly_pubkey.
- *
- * Returns: 1 if the public key was successfully converted
- * 0 otherwise
- *
- * Args: ctx: pointer to a context object (cannot be NULL)
- * Out: xonly_pubkey: pointer to an x-only public key object for placing the
- * converted public key (cannot be NULL)
- * pk_parity: 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. (can be NULL)
- * In: pubkey: pointer to a public key that is converted (cannot be NULL)
- */
- 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 initialized for verification
- * (cannot be NULL)
- * Out: output_pubkey: pointer to a public key to store the result. Will be set
- * to an invalid value if this function returns 0 (cannot
- * be NULL)
- * In: internal_pubkey: pointer to an x-only pubkey to apply the tweak to.
- * (cannot be NULL).
- * 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) (cannot be NULL).
- */
- 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 initialized for verification
- * (cannot be NULL)
- * In: tweaked_pubkey32: pointer to a serialized xonly_pubkey (cannot be NULL)
- * 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 (cannot be NULL)
- * tweak32: pointer to a 32-byte tweak (cannot be NULL)
- */
- 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, initialized for signing (cannot be NULL)
- * Out: keypair: pointer to the created keypair (cannot be NULL)
- * In: seckey: pointer to a 32-byte secret key (cannot be NULL)
- */
- 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 public key from a keypair.
- *
- * Returns: 0 if the arguments are invalid. 1 otherwise.
- * Args: ctx: pointer to a context object (cannot be NULL)
- * 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.
- * (cannot be NULL)
- * In: keypair: pointer to a keypair (cannot be NULL)
- */
- 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: 0 if the arguments are invalid. 1 otherwise.
- * Args: ctx: pointer to a context object (cannot be NULL)
- * 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 (cannot be
- * NULL).
- * pk_parity: pointer to an integer that will be set to the pk_parity
- * argument of secp256k1_xonly_pubkey_from_pubkey (can be NULL).
- * In: keypair: pointer to a keypair (cannot be NULL)
- */
- 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 initialized for verification
- * (cannot be NULL)
- * In/Out: keypair: pointer to a keypair to apply the tweak to. Will be set to
- * an invalid value if this function returns 0 (cannot be
- * NULL).
- * 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) (cannot be NULL).
- */
- 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 */
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