Update secp256k1 library to 0.6.0 (#5254)

This commit is contained in:
Michael Legleux
2025-01-27 11:47:47 -08:00
committed by GitHub
parent ed4870cdb4
commit b6e3453f49
109 changed files with 12713 additions and 13537 deletions

View File

@@ -49,19 +49,6 @@ extern "C" {
*/
typedef struct secp256k1_context_struct secp256k1_context;
/** Opaque data structure that holds rewritable "scratch space"
*
* The purpose of this structure is to replace dynamic memory allocations,
* because we target architectures where this may not be available. It is
* essentially a resizable (within specified parameters) block of bytes,
* which is initially created either by memory allocation or TODO as a pointer
* into some fixed rewritable space.
*
* Unlike the context object, this cannot safely be shared between threads
* without additional synchronization logic.
*/
typedef struct secp256k1_scratch_space_struct secp256k1_scratch_space;
/** Opaque data structure that holds a parsed and valid public key.
*
* The exact representation of data inside is implementation defined and not
@@ -71,11 +58,11 @@ typedef struct secp256k1_scratch_space_struct secp256k1_scratch_space;
* use secp256k1_ec_pubkey_serialize and secp256k1_ec_pubkey_parse. To
* compare keys, use secp256k1_ec_pubkey_cmp.
*/
typedef struct {
typedef struct secp256k1_pubkey {
unsigned char data[64];
} secp256k1_pubkey;
/** Opaque data structured that holds a parsed ECDSA signature.
/** Opaque data structure 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
@@ -84,7 +71,7 @@ typedef struct {
* comparison, use the secp256k1_ecdsa_signature_serialize_* and
* secp256k1_ecdsa_signature_parse_* functions.
*/
typedef struct {
typedef struct secp256k1_ecdsa_signature {
unsigned char data[64];
} secp256k1_ecdsa_signature;
@@ -133,28 +120,45 @@ typedef int (*secp256k1_nonce_function)(
# define SECP256K1_NO_BUILD
#endif
/* Symbol visibility. See libtool manual, section "Windows DLLs". */
#if defined(_WIN32) && !defined(__GNUC__)
# ifdef SECP256K1_BUILD
# ifdef DLL_EXPORT
# define SECP256K1_API __declspec (dllexport)
# define SECP256K1_API_VAR extern __declspec (dllexport)
/* Symbol visibility. */
#if defined(_WIN32)
/* GCC for Windows (e.g., MinGW) accepts the __declspec syntax
* for MSVC compatibility. A __declspec declaration implies (but is not
* exactly equivalent to) __attribute__ ((visibility("default"))), and so we
* actually want __declspec even on GCC, see "Microsoft Windows Function
* Attributes" in the GCC manual and the recommendations in
* https://gcc.gnu.org/wiki/Visibility. */
# if defined(SECP256K1_BUILD)
# if defined(DLL_EXPORT) || defined(SECP256K1_DLL_EXPORT)
/* Building libsecp256k1 as a DLL.
* 1. If using Libtool, it defines DLL_EXPORT automatically.
* 2. In other cases, SECP256K1_DLL_EXPORT must be defined. */
# define SECP256K1_API extern __declspec (dllexport)
# else
/* Building libsecp256k1 as a static library on Windows.
* No declspec is needed, and so we would want the non-Windows-specific
* logic below take care of this case. However, this may result in setting
* __attribute__ ((visibility("default"))), which is supposed to be a noop
* on Windows but may trigger warnings when compiling with -flto due to a
* bug in GCC, see
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116478 . */
# define SECP256K1_API extern
# endif
# elif defined _MSC_VER
# define SECP256K1_API
# define SECP256K1_API_VAR extern __declspec (dllimport)
# elif defined DLL_EXPORT
# define SECP256K1_API __declspec (dllimport)
# define SECP256K1_API_VAR extern __declspec (dllimport)
/* The user must define SECP256K1_STATIC when consuming libsecp256k1 as a static
* library on Windows. */
# elif !defined(SECP256K1_STATIC)
/* Consuming libsecp256k1 as a DLL. */
# define SECP256K1_API extern __declspec (dllimport)
# endif
#endif
#ifndef SECP256K1_API
/* All cases not captured by the Windows-specific logic. */
# if defined(__GNUC__) && (__GNUC__ >= 4) && defined(SECP256K1_BUILD)
# define SECP256K1_API __attribute__ ((visibility ("default")))
# define SECP256K1_API_VAR extern __attribute__ ((visibility ("default")))
/* Building libsecp256k1 using GCC or compatible. */
# define SECP256K1_API extern __attribute__ ((visibility ("default")))
# else
# define SECP256K1_API
# define SECP256K1_API_VAR extern
/* Fall back to standard C's extern. */
# define SECP256K1_API extern
# endif
#endif
@@ -226,10 +230,10 @@ typedef int (*secp256k1_nonce_function)(
*
* It is highly recommended to call secp256k1_selftest before using this context.
*/
SECP256K1_API_VAR const secp256k1_context *secp256k1_context_static;
SECP256K1_API const secp256k1_context *secp256k1_context_static;
/** Deprecated alias for secp256k1_context_static. */
SECP256K1_API_VAR const secp256k1_context *secp256k1_context_no_precomp
SECP256K1_API const secp256k1_context *secp256k1_context_no_precomp
SECP256K1_DEPRECATED("Use secp256k1_context_static instead");
/** Perform basic self tests (to be used in conjunction with secp256k1_context_static)
@@ -258,7 +262,7 @@ SECP256K1_API void secp256k1_selftest(void);
* memory allocation entirely, see secp256k1_context_static and the functions in
* secp256k1_preallocated.h.
*
* Returns: a newly created context object.
* Returns: pointer to a newly created context object.
* In: flags: Always set to SECP256K1_CONTEXT_NONE (see below).
*
* The only valid non-deprecated flag in recent library versions is
@@ -289,8 +293,8 @@ SECP256K1_API secp256k1_context *secp256k1_context_create(
* Cloning secp256k1_context_static is not possible, and should not be emulated by
* the caller (e.g., using memcpy). Create a new context instead.
*
* Returns: a newly created context object.
* Args: ctx: an existing context to copy (not secp256k1_context_static)
* Returns: pointer to a newly created context object.
* Args: ctx: pointer to a context to copy (not secp256k1_context_static).
*/
SECP256K1_API secp256k1_context *secp256k1_context_clone(
const secp256k1_context *ctx
@@ -306,7 +310,7 @@ SECP256K1_API secp256k1_context *secp256k1_context_clone(
* behaviour is undefined. In that case, secp256k1_context_preallocated_destroy must
* be used instead.
*
* Args: ctx: an existing context to destroy, constructed using
* Args: ctx: pointer to a context to destroy, constructed using
* secp256k1_context_create or secp256k1_context_clone
* (i.e., not secp256k1_context_static).
*/
@@ -343,8 +347,8 @@ SECP256K1_API void secp256k1_context_destroy(
* fails. In this case, the corresponding default handler will be called with
* the data pointer argument set to NULL.
*
* Args: ctx: an existing context object.
* In: fun: a pointer to a function to call when an illegal argument is
* Args: ctx: pointer to a context object.
* In: fun: pointer to a function to call when an illegal argument is
* passed to the API, taking a message and an opaque pointer.
* (NULL restores the default handler.)
* data: the opaque pointer to pass to fun above, must be NULL for the default handler.
@@ -370,8 +374,8 @@ SECP256K1_API void secp256k1_context_set_illegal_callback(
* for that). After this callback returns, anything may happen, including
* crashing.
*
* Args: ctx: an existing context object.
* In: fun: a pointer to a function to call when an internal error occurs,
* Args: ctx: pointer to a context object.
* In: fun: pointer to a function to call when an internal error occurs,
* taking a message and an opaque pointer (NULL restores the
* default handler, see secp256k1_context_set_illegal_callback
* for details).
@@ -385,34 +389,11 @@ SECP256K1_API void secp256k1_context_set_error_callback(
const void *data
) SECP256K1_ARG_NONNULL(1);
/** Create a secp256k1 scratch space object.
*
* Returns: a newly created scratch space.
* Args: ctx: an existing context object.
* In: size: amount of memory to be available as scratch space. Some extra
* (<100 bytes) will be allocated for extra accounting.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT secp256k1_scratch_space *secp256k1_scratch_space_create(
const secp256k1_context *ctx,
size_t size
) SECP256K1_ARG_NONNULL(1);
/** Destroy a secp256k1 scratch space.
*
* The pointer may not be used afterwards.
* Args: ctx: a secp256k1 context object.
* scratch: space to destroy
*/
SECP256K1_API void secp256k1_scratch_space_destroy(
const secp256k1_context *ctx,
secp256k1_scratch_space *scratch
) SECP256K1_ARG_NONNULL(1);
/** Parse a variable-length public key into the 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.
* Args: ctx: pointer to a context object.
* Out: pubkey: pointer to a pubkey object. If 1 is returned, it is set to a
* parsed version of input. If not, its value is undefined.
* In: input: pointer to a serialized public key
@@ -432,14 +413,14 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_parse(
/** Serialize a pubkey object into a serialized byte sequence.
*
* Returns: 1 always.
* Args: ctx: a secp256k1 context object.
* Out: output: a pointer to a 65-byte (if compressed==0) or 33-byte (if
* Args: ctx: pointer to a context object.
* Out: output: pointer to a 65-byte (if compressed==0) or 33-byte (if
* compressed==1) byte array to place the serialized key
* in.
* In/Out: outputlen: a pointer to an integer which is initially set to the
* In/Out: outputlen: pointer to an integer which is initially set to the
* size of output, and is overwritten with the written
* size.
* In: pubkey: a pointer to a secp256k1_pubkey containing an
* In: pubkey: pointer to a secp256k1_pubkey containing an
* initialized public key.
* flags: SECP256K1_EC_COMPRESSED if serialization should be in
* compressed format, otherwise SECP256K1_EC_UNCOMPRESSED.
@@ -457,7 +438,7 @@ SECP256K1_API int secp256k1_ec_pubkey_serialize(
* 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.
* Args: ctx: pointer to a context object
* In: pubkey1: first public key to compare
* pubkey2: second public key to compare
*/
@@ -467,12 +448,26 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_cmp(
const secp256k1_pubkey *pubkey2
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Sort public keys using lexicographic (of compressed serialization) order
*
* Returns: 0 if the arguments are invalid. 1 otherwise.
*
* Args: ctx: pointer to a context object
* In: pubkeys: array of pointers to pubkeys to sort
* n_pubkeys: number of elements in the pubkeys array
*/
SECP256K1_API int secp256k1_ec_pubkey_sort(
const secp256k1_context *ctx,
const secp256k1_pubkey **pubkeys,
size_t n_pubkeys
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2);
/** Parse an ECDSA signature in compact (64 bytes) format.
*
* Returns: 1 when the signature could be parsed, 0 otherwise.
* Args: ctx: a secp256k1 context object
* Out: sig: a pointer to a signature object
* In: input64: a pointer to the 64-byte array to parse
* Args: ctx: pointer to a context object
* Out: sig: pointer to a signature object
* In: input64: pointer to the 64-byte array to parse
*
* The signature must consist of a 32-byte big endian R value, followed by a
* 32-byte big endian S value. If R or S fall outside of [0..order-1], the
@@ -491,9 +486,9 @@ SECP256K1_API int secp256k1_ecdsa_signature_parse_compact(
/** Parse a DER ECDSA signature.
*
* Returns: 1 when the signature could be parsed, 0 otherwise.
* Args: ctx: a secp256k1 context object
* Out: sig: a pointer to a signature object
* In: input: a pointer to the signature to be parsed
* Args: ctx: pointer to a context object
* Out: sig: pointer to a signature object
* In: input: pointer to the signature to be parsed
* inputlen: the length of the array pointed to be input
*
* This function will accept any valid DER encoded signature, even if the
@@ -513,13 +508,13 @@ SECP256K1_API int secp256k1_ecdsa_signature_parse_der(
/** Serialize an ECDSA signature in DER format.
*
* Returns: 1 if enough space was available to serialize, 0 otherwise
* Args: ctx: a secp256k1 context object
* Out: output: a pointer to an array to store the DER serialization
* In/Out: outputlen: a pointer to a length integer. Initially, this integer
* Args: ctx: pointer to a context object
* Out: output: pointer to an array to store the DER serialization
* In/Out: outputlen: pointer to a length integer. Initially, this integer
* should be set to the length of output. After the call
* it will be set to the length of the serialization (even
* if 0 was returned).
* In: sig: a pointer to an initialized signature object
* In: sig: pointer to an initialized signature object
*/
SECP256K1_API int secp256k1_ecdsa_signature_serialize_der(
const secp256k1_context *ctx,
@@ -531,9 +526,9 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_der(
/** Serialize an ECDSA signature in compact (64 byte) format.
*
* Returns: 1
* Args: ctx: a secp256k1 context object
* Out: output64: a pointer to a 64-byte array to store the compact serialization
* In: sig: a pointer to an initialized signature object
* Args: ctx: pointer to a context object
* Out: output64: pointer to a 64-byte array to store the compact serialization
* In: sig: pointer to an initialized signature object
*
* See secp256k1_ecdsa_signature_parse_compact for details about the encoding.
*/
@@ -547,7 +542,7 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_compact(
*
* Returns: 1: correct signature
* 0: incorrect or unparseable signature
* Args: ctx: a secp256k1 context object.
* Args: ctx: pointer to a context object
* In: sig: the signature being verified.
* msghash32: the 32-byte message hash being verified.
* The verifier must make sure to apply a cryptographic
@@ -578,12 +573,12 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
/** Convert a signature to a normalized lower-S form.
*
* Returns: 1 if sigin was not normalized, 0 if it already was.
* Args: ctx: a secp256k1 context object
* Out: sigout: a pointer to a signature to fill with the normalized form,
* Args: ctx: pointer to a context object
* Out: sigout: pointer to a signature to fill with the normalized form,
* or copy if the input was already normalized. (can be NULL if
* you're only interested in whether the input was already
* normalized).
* In: sigin: a pointer to a signature to check/normalize (can be identical to sigout)
* In: sigin: pointer to a signature to check/normalize (can be identical to sigout)
*
* With ECDSA a third-party can forge a second distinct signature of the same
* message, given a single initial signature, but without knowing the key. This
@@ -626,10 +621,10 @@ SECP256K1_API int secp256k1_ecdsa_signature_normalize(
* If a data pointer is passed, it is assumed to be a pointer to 32 bytes of
* extra entropy.
*/
SECP256K1_API_VAR const secp256k1_nonce_function secp256k1_nonce_function_rfc6979;
SECP256K1_API const secp256k1_nonce_function secp256k1_nonce_function_rfc6979;
/** A default safe nonce generation function (currently equal to secp256k1_nonce_function_rfc6979). */
SECP256K1_API_VAR const secp256k1_nonce_function secp256k1_nonce_function_default;
SECP256K1_API const secp256k1_nonce_function secp256k1_nonce_function_default;
/** Create an ECDSA signature.
*
@@ -658,12 +653,14 @@ SECP256K1_API int secp256k1_ecdsa_sign(
const void *ndata
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
/** Verify an ECDSA secret key.
/** Verify an elliptic curve secret key.
*
* A secret key is valid if it is not 0 and less than the secp256k1 curve order
* when interpreted as an integer (most significant byte first). The
* probability of choosing a 32-byte string uniformly at random which is an
* invalid secret key is negligible.
* invalid secret key is negligible. However, if it does happen it should
* be assumed that the randomness source is severely broken and there should
* be no retry.
*
* Returns: 1: secret key is valid
* 0: secret key is invalid
@@ -733,10 +730,10 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_negate(
* invalid according to secp256k1_ec_seckey_verify, this
* function returns 0. seckey will be set to some unspecified
* 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).
* In: tweak32: pointer to a 32-byte tweak, which must be valid according to
* secp256k1_ec_seckey_verify or 32 zero bytes. For uniformly
* random 32-byte tweaks, the chance of being invalid is
* negligible (around 1 in 2^128).
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_add(
const secp256k1_context *ctx,
@@ -761,10 +758,10 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add(
* Args: ctx: pointer to a context object.
* In/Out: pubkey: pointer to a public key object. pubkey 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).
* In: tweak32: pointer to a 32-byte tweak, which must be valid according to
* secp256k1_ec_seckey_verify or 32 zero bytes. For uniformly
* random 32-byte tweaks, the chance of being invalid is
* negligible (around 1 in 2^128).
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add(
const secp256k1_context *ctx,

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@@ -27,11 +27,11 @@ typedef int (*secp256k1_ecdh_hash_function)(
/** An implementation of SHA256 hash function that applies to compressed public key.
* Populates the output parameter with 32 bytes. */
SECP256K1_API_VAR const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_sha256;
SECP256K1_API const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_sha256;
/** A default ECDH hash function (currently equal to secp256k1_ecdh_hash_function_sha256).
* Populates the output parameter with 32 bytes. */
SECP256K1_API_VAR const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_default;
SECP256K1_API const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_default;
/** Compute an EC Diffie-Hellman secret in constant time
*
@@ -39,7 +39,7 @@ SECP256K1_API_VAR const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_functio
* 0: scalar was invalid (zero or overflow) or hashfp returned 0
* Args: ctx: pointer to a context object.
* Out: output: pointer to an array to be filled by hashfp.
* In: pubkey: a pointer to a secp256k1_pubkey containing an initialized public key.
* In: pubkey: pointer to a secp256k1_pubkey containing an initialized public key.
* seckey: 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

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@@ -0,0 +1,200 @@
#ifndef SECP256K1_ELLSWIFT_H
#define SECP256K1_ELLSWIFT_H
#include "secp256k1.h"
#ifdef __cplusplus
extern "C" {
#endif
/* This module provides an implementation of ElligatorSwift as well as a
* version of x-only ECDH using it (including compatibility with BIP324).
*
* ElligatorSwift is described in https://eprint.iacr.org/2022/759 by
* Chavez-Saab, Rodriguez-Henriquez, and Tibouchi. It permits encoding
* uniformly chosen public keys as 64-byte arrays which are indistinguishable
* from uniformly random arrays.
*
* Let f be the function from pairs of field elements to point X coordinates,
* defined as follows (all operations modulo p = 2^256 - 2^32 - 977)
* f(u,t):
* - Let C = 0xa2d2ba93507f1df233770c2a797962cc61f6d15da14ecd47d8d27ae1cd5f852,
* a square root of -3.
* - If u=0, set u=1 instead.
* - If t=0, set t=1 instead.
* - If u^3 + t^2 + 7 = 0, multiply t by 2.
* - Let X = (u^3 + 7 - t^2) / (2 * t)
* - Let Y = (X + t) / (C * u)
* - Return the first in [u + 4 * Y^2, (-X/Y - u) / 2, (X/Y - u) / 2] that is an
* X coordinate on the curve (at least one of them is, for any u and t).
*
* Then an ElligatorSwift encoding of x consists of the 32-byte big-endian
* encodings of field elements u and t concatenated, where f(u,t) = x.
* The encoding algorithm is described in the paper, and effectively picks a
* uniformly random pair (u,t) among those which encode x.
*
* If the Y coordinate is relevant, it is given the same parity as t.
*
* Changes w.r.t. the paper:
* - The u=0, t=0, and u^3+t^2+7=0 conditions result in decoding to the point
* at infinity in the paper. Here they are remapped to finite points.
* - The paper uses an additional encoding bit for the parity of y. Here the
* parity of t is used (negating t does not affect the decoded x coordinate,
* so this is possible).
*
* For mathematical background about the scheme, see the doc/ellswift.md file.
*/
/** A pointer to a function used by secp256k1_ellswift_xdh to hash the shared X
* coordinate along with the encoded public keys to a uniform shared secret.
*
* Returns: 1 if a shared secret was successfully computed.
* 0 will cause secp256k1_ellswift_xdh to fail and return 0.
* Other return values are not allowed, and the behaviour of
* secp256k1_ellswift_xdh is undefined for other return values.
* Out: output: pointer to an array to be filled by the function
* In: x32: pointer to the 32-byte serialized X coordinate
* of the resulting shared point (will not be NULL)
* ell_a64: pointer to the 64-byte encoded public key of party A
* (will not be NULL)
* ell_b64: pointer to the 64-byte encoded public key of party B
* (will not be NULL)
* data: arbitrary data pointer that is passed through
*/
typedef int (*secp256k1_ellswift_xdh_hash_function)(
unsigned char *output,
const unsigned char *x32,
const unsigned char *ell_a64,
const unsigned char *ell_b64,
void *data
);
/** An implementation of an secp256k1_ellswift_xdh_hash_function which uses
* SHA256(prefix64 || ell_a64 || ell_b64 || x32), where prefix64 is the 64-byte
* array pointed to by data. */
SECP256K1_API const secp256k1_ellswift_xdh_hash_function secp256k1_ellswift_xdh_hash_function_prefix;
/** An implementation of an secp256k1_ellswift_xdh_hash_function compatible with
* BIP324. It returns H_tag(ell_a64 || ell_b64 || x32), where H_tag is the
* BIP340 tagged hash function with tag "bip324_ellswift_xonly_ecdh". Equivalent
* to secp256k1_ellswift_xdh_hash_function_prefix with prefix64 set to
* SHA256("bip324_ellswift_xonly_ecdh")||SHA256("bip324_ellswift_xonly_ecdh").
* The data argument is ignored. */
SECP256K1_API const secp256k1_ellswift_xdh_hash_function secp256k1_ellswift_xdh_hash_function_bip324;
/** Construct a 64-byte ElligatorSwift encoding of a given pubkey.
*
* Returns: 1 always.
* Args: ctx: pointer to a context object
* Out: ell64: pointer to a 64-byte array to be filled
* In: pubkey: pointer to a secp256k1_pubkey containing an
* initialized public key
* rnd32: pointer to 32 bytes of randomness
*
* It is recommended that rnd32 consists of 32 uniformly random bytes, not
* known to any adversary trying to detect whether public keys are being
* encoded, though 16 bytes of randomness (padded to an array of 32 bytes,
* e.g., with zeros) suffice to make the result indistinguishable from
* uniform. The randomness in rnd32 must not be a deterministic function of
* the pubkey (it can be derived from the private key, though).
*
* It is not guaranteed that the computed encoding is stable across versions
* of the library, even if all arguments to this function (including rnd32)
* are the same.
*
* This function runs in variable time.
*/
SECP256K1_API int secp256k1_ellswift_encode(
const secp256k1_context *ctx,
unsigned char *ell64,
const secp256k1_pubkey *pubkey,
const unsigned char *rnd32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
/** Decode a 64-bytes ElligatorSwift encoded public key.
*
* Returns: always 1
* Args: ctx: pointer to a context object
* Out: pubkey: pointer to a secp256k1_pubkey that will be filled
* In: ell64: pointer to a 64-byte array to decode
*
* This function runs in variable time.
*/
SECP256K1_API int secp256k1_ellswift_decode(
const secp256k1_context *ctx,
secp256k1_pubkey *pubkey,
const unsigned char *ell64
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Compute an ElligatorSwift public key for a secret key.
*
* Returns: 1: secret was valid, public key was stored.
* 0: secret was invalid, try again.
* Args: ctx: pointer to a context object
* Out: ell64: pointer to a 64-byte array to receive the ElligatorSwift
* public key
* In: seckey32: pointer to a 32-byte secret key
* auxrnd32: (optional) pointer to 32 bytes of randomness
*
* Constant time in seckey and auxrnd32, but not in the resulting public key.
*
* It is recommended that auxrnd32 contains 32 uniformly random bytes, though
* it is optional (and does result in encodings that are indistinguishable from
* uniform even without any auxrnd32). It differs from the (mandatory) rnd32
* argument to secp256k1_ellswift_encode in this regard.
*
* This function can be used instead of calling secp256k1_ec_pubkey_create
* followed by secp256k1_ellswift_encode. It is safer, as it uses the secret
* key as entropy for the encoding (supplemented with auxrnd32, if provided).
*
* Like secp256k1_ellswift_encode, this function does not guarantee that the
* computed encoding is stable across versions of the library, even if all
* arguments (including auxrnd32) are the same.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ellswift_create(
const secp256k1_context *ctx,
unsigned char *ell64,
const unsigned char *seckey32,
const unsigned char *auxrnd32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Given a private key, and ElligatorSwift public keys sent in both directions,
* compute a shared secret using x-only Elliptic Curve Diffie-Hellman (ECDH).
*
* Returns: 1: shared secret was successfully computed
* 0: secret was invalid or hashfp returned 0
* Args: ctx: pointer to a context object.
* Out: output: pointer to an array to be filled by hashfp.
* In: ell_a64: pointer to the 64-byte encoded public key of party A
* (will not be NULL)
* ell_b64: pointer to the 64-byte encoded public key of party B
* (will not be NULL)
* seckey32: pointer to our 32-byte secret key
* party: boolean indicating which party we are: zero if we are
* party A, non-zero if we are party B. seckey32 must be
* the private key corresponding to that party's ell_?64.
* This correspondence is not checked.
* hashfp: pointer to a hash function.
* data: arbitrary data pointer passed through to hashfp.
*
* Constant time in seckey32.
*
* This function is more efficient than decoding the public keys, and performing
* ECDH on them.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ellswift_xdh(
const secp256k1_context *ctx,
unsigned char *output,
const unsigned char *ell_a64,
const unsigned char *ell_b64,
const unsigned char *seckey32,
int party,
secp256k1_ellswift_xdh_hash_function hashfp,
void *data
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5) SECP256K1_ARG_NONNULL(7);
#ifdef __cplusplus
}
#endif
#endif /* SECP256K1_ELLSWIFT_H */

View File

@@ -19,7 +19,7 @@ extern "C" {
* use secp256k1_xonly_pubkey_serialize and secp256k1_xonly_pubkey_parse. To
* compare keys, use secp256k1_xonly_pubkey_cmp.
*/
typedef struct {
typedef struct secp256k1_xonly_pubkey {
unsigned char data[64];
} secp256k1_xonly_pubkey;
@@ -30,7 +30,7 @@ typedef struct {
* 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 {
typedef struct secp256k1_keypair {
unsigned char data[96];
} secp256k1_keypair;
@@ -39,7 +39,7 @@ typedef struct {
* 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.
* Args: ctx: pointer to a 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.
@@ -54,9 +54,9 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_parse(
*
* 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.
* Args: ctx: pointer to a context object.
* Out: output32: pointer to a 32-byte array to place the serialized key in.
* In: pubkey: pointer to a secp256k1_xonly_pubkey containing an initialized public key.
*/
SECP256K1_API int secp256k1_xonly_pubkey_serialize(
const secp256k1_context *ctx,
@@ -69,7 +69,7 @@ SECP256K1_API int secp256k1_xonly_pubkey_serialize(
* 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.
* Args: ctx: pointer to a context object.
* In: pubkey1: first public key to compare
* pubkey2: second public key to compare
*/
@@ -112,10 +112,10 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_from_pubke
* 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).
* tweak32: pointer to a 32-byte tweak, which must be valid
* according to secp256k1_ec_seckey_verify or 32 zero
* bytes. For uniformly random 32-byte tweaks, 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,
@@ -155,10 +155,13 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_tweak_add_
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.
/** Compute the keypair for a valid secret key.
*
* Returns: 1: secret was valid, keypair is ready to use
* 0: secret was invalid, try again with a different secret
* See the documentation of `secp256k1_ec_seckey_verify` for more information
* about the validity of secret keys.
*
* Returns: 1: secret key is valid
* 0: secret key is invalid
* 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.
@@ -185,9 +188,8 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_sec(
/** 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.
* Args: ctx: pointer to a context object.
* Out: pubkey: pointer to a pubkey object, set to the keypair public key.
* In: keypair: pointer to a keypair.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_pub(
@@ -203,9 +205,8 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_pub(
*
* 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.
* Out: pubkey: pointer to an xonly_pubkey object, set to the keypair
* public key after converting it to an xonly_pubkey.
* 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.
@@ -231,10 +232,10 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_xonly_pub(
* 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).
* In: tweak32: pointer to a 32-byte tweak, which must be valid according to
* secp256k1_ec_seckey_verify or 32 zero bytes. For uniformly
* random 32-byte tweaks, 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,

View File

@@ -0,0 +1,588 @@
#ifndef SECP256K1_MUSIG_H
#define SECP256K1_MUSIG_H
#include "secp256k1_extrakeys.h"
#ifdef __cplusplus
extern "C" {
#endif
#include <stddef.h>
#include <stdint.h>
/** This module implements BIP 327 "MuSig2 for BIP340-compatible
* Multi-Signatures"
* (https://github.com/bitcoin/bips/blob/master/bip-0327.mediawiki)
* v1.0.0. You can find an example demonstrating the musig module in
* examples/musig.c.
*
* The module also supports BIP 341 ("Taproot") public key tweaking.
*
* It is recommended to read the documentation in this include file carefully.
* Further notes on API usage can be found in doc/musig.md
*
* Since the first version of MuSig is essentially replaced by MuSig2, we use
* MuSig, musig and MuSig2 synonymously unless noted otherwise.
*/
/** Opaque data structures
*
* The exact representation of data inside the opaque data structures is
* implementation defined and not guaranteed to be portable between different
* platforms or versions. With the exception of `secp256k1_musig_secnonce`, the
* data structures can be safely copied/moved. If you need to convert to a
* format suitable for storage, transmission, or comparison, use the
* corresponding serialization and parsing functions.
*/
/** Opaque data structure that caches information about public key aggregation.
*
* Guaranteed to be 197 bytes in size. No serialization and parsing functions
* (yet).
*/
typedef struct secp256k1_musig_keyagg_cache {
unsigned char data[197];
} secp256k1_musig_keyagg_cache;
/** Opaque data structure that holds a signer's _secret_ nonce.
*
* Guaranteed to be 132 bytes in size.
*
* WARNING: This structure MUST NOT be copied or read or written to directly. A
* signer who is online throughout the whole process and can keep this
* structure in memory can use the provided API functions for a safe standard
* workflow.
*
* Copying this data structure can result in nonce reuse which will leak the
* secret signing key.
*/
typedef struct secp256k1_musig_secnonce {
unsigned char data[132];
} secp256k1_musig_secnonce;
/** Opaque data structure that holds a signer's public nonce.
*
* Guaranteed to be 132 bytes in size. Serialized and parsed with
* `musig_pubnonce_serialize` and `musig_pubnonce_parse`.
*/
typedef struct secp256k1_musig_pubnonce {
unsigned char data[132];
} secp256k1_musig_pubnonce;
/** Opaque data structure that holds an aggregate public nonce.
*
* Guaranteed to be 132 bytes in size. Serialized and parsed with
* `musig_aggnonce_serialize` and `musig_aggnonce_parse`.
*/
typedef struct secp256k1_musig_aggnonce {
unsigned char data[132];
} secp256k1_musig_aggnonce;
/** Opaque data structure that holds a MuSig session.
*
* This structure is not required to be kept secret for the signing protocol to
* be secure. Guaranteed to be 133 bytes in size. No serialization and parsing
* functions (yet).
*/
typedef struct secp256k1_musig_session {
unsigned char data[133];
} secp256k1_musig_session;
/** Opaque data structure that holds a partial MuSig signature.
*
* Guaranteed to be 36 bytes in size. Serialized and parsed with
* `musig_partial_sig_serialize` and `musig_partial_sig_parse`.
*/
typedef struct secp256k1_musig_partial_sig {
unsigned char data[36];
} secp256k1_musig_partial_sig;
/** Parse a signer's public nonce.
*
* Returns: 1 when the nonce could be parsed, 0 otherwise.
* Args: ctx: pointer to a context object
* Out: nonce: pointer to a nonce object
* In: in66: pointer to the 66-byte nonce to be parsed
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_pubnonce_parse(
const secp256k1_context *ctx,
secp256k1_musig_pubnonce *nonce,
const unsigned char *in66
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Serialize a signer's public nonce
*
* Returns: 1 always
* Args: ctx: pointer to a context object
* Out: out66: pointer to a 66-byte array to store the serialized nonce
* In: nonce: pointer to the nonce
*/
SECP256K1_API int secp256k1_musig_pubnonce_serialize(
const secp256k1_context *ctx,
unsigned char *out66,
const secp256k1_musig_pubnonce *nonce
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Parse an aggregate public nonce.
*
* Returns: 1 when the nonce could be parsed, 0 otherwise.
* Args: ctx: pointer to a context object
* Out: nonce: pointer to a nonce object
* In: in66: pointer to the 66-byte nonce to be parsed
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_aggnonce_parse(
const secp256k1_context *ctx,
secp256k1_musig_aggnonce *nonce,
const unsigned char *in66
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Serialize an aggregate public nonce
*
* Returns: 1 always
* Args: ctx: pointer to a context object
* Out: out66: pointer to a 66-byte array to store the serialized nonce
* In: nonce: pointer to the nonce
*/
SECP256K1_API int secp256k1_musig_aggnonce_serialize(
const secp256k1_context *ctx,
unsigned char *out66,
const secp256k1_musig_aggnonce *nonce
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Parse a MuSig partial signature.
*
* 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: in32: pointer to the 32-byte signature to be parsed
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_partial_sig_parse(
const secp256k1_context *ctx,
secp256k1_musig_partial_sig *sig,
const unsigned char *in32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Serialize a MuSig partial signature
*
* Returns: 1 always
* Args: ctx: pointer to a context object
* Out: out32: pointer to a 32-byte array to store the serialized signature
* In: sig: pointer to the signature
*/
SECP256K1_API int secp256k1_musig_partial_sig_serialize(
const secp256k1_context *ctx,
unsigned char *out32,
const secp256k1_musig_partial_sig *sig
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Computes an aggregate public key and uses it to initialize a keyagg_cache
*
* Different orders of `pubkeys` result in different `agg_pk`s.
*
* Before aggregating, the pubkeys can be sorted with `secp256k1_ec_pubkey_sort`
* which ensures the same `agg_pk` result for the same multiset of pubkeys.
* This is useful to do before `pubkey_agg`, such that the order of pubkeys
* does not affect the aggregate public key.
*
* Returns: 0 if the arguments are invalid, 1 otherwise
* Args: ctx: pointer to a context object
* Out: agg_pk: the MuSig-aggregated x-only public key. If you do not need it,
* this arg can be NULL.
* keyagg_cache: if non-NULL, pointer to a musig_keyagg_cache struct that
* is required for signing (or observing the signing session
* and verifying partial signatures).
* In: pubkeys: input array of pointers to public keys to aggregate. The order
* is important; a different order will result in a different
* aggregate public key.
* n_pubkeys: length of pubkeys array. Must be greater than 0.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_pubkey_agg(
const secp256k1_context *ctx,
secp256k1_xonly_pubkey *agg_pk,
secp256k1_musig_keyagg_cache *keyagg_cache,
const secp256k1_pubkey * const *pubkeys,
size_t n_pubkeys
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(4);
/** Obtain the aggregate public key from a keyagg_cache.
*
* This is only useful if you need the non-xonly public key, in particular for
* plain (non-xonly) tweaking or batch-verifying multiple key aggregations
* (not implemented).
*
* Returns: 0 if the arguments are invalid, 1 otherwise
* Args: ctx: pointer to a context object
* Out: agg_pk: the MuSig-aggregated public key.
* In: keyagg_cache: pointer to a `musig_keyagg_cache` struct initialized by
* `musig_pubkey_agg`
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_pubkey_get(
const secp256k1_context *ctx,
secp256k1_pubkey *agg_pk,
const secp256k1_musig_keyagg_cache *keyagg_cache
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Apply plain "EC" tweaking to a public key in a given keyagg_cache by adding
* the generator multiplied with `tweak32` to it. This is useful for deriving
* child keys from an aggregate public key via BIP 32 where `tweak32` is set to
* a hash as defined in BIP 32.
*
* Callers are responsible for deriving `tweak32` in a way that does not reduce
* the security of MuSig (for example, by following BIP 32).
*
* The tweaking method is the same as `secp256k1_ec_pubkey_tweak_add`. So after
* the following pseudocode buf and buf2 have identical contents (absent
* earlier failures).
*
* secp256k1_musig_pubkey_agg(..., keyagg_cache, pubkeys, ...)
* secp256k1_musig_pubkey_get(..., agg_pk, keyagg_cache)
* secp256k1_musig_pubkey_ec_tweak_add(..., output_pk, tweak32, keyagg_cache)
* secp256k1_ec_pubkey_serialize(..., buf, ..., output_pk, ...)
* secp256k1_ec_pubkey_tweak_add(..., agg_pk, tweak32)
* secp256k1_ec_pubkey_serialize(..., buf2, ..., agg_pk, ...)
*
* This function is required if you want to _sign_ for a tweaked aggregate key.
* If you are only computing a public key but not intending to create a
* signature for it, use `secp256k1_ec_pubkey_tweak_add` instead.
*
* Returns: 0 if the arguments are invalid, 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. If you
* do not need it, this arg can be NULL.
* In/Out: keyagg_cache: pointer to a `musig_keyagg_cache` struct initialized by
* `musig_pubkey_agg`
* In: tweak32: pointer to a 32-byte tweak. The tweak is valid if it passes
* `secp256k1_ec_seckey_verify` and is not equal to the
* secret key corresponding to the public key represented
* by keyagg_cache or its negation. 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_musig_pubkey_ec_tweak_add(
const secp256k1_context *ctx,
secp256k1_pubkey *output_pubkey,
secp256k1_musig_keyagg_cache *keyagg_cache,
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
/** Apply x-only tweaking to a public key in a given keyagg_cache by adding the
* generator multiplied with `tweak32` to it. This is useful for creating
* Taproot outputs where `tweak32` is set to a TapTweak hash as defined in BIP
* 341.
*
* Callers are responsible for deriving `tweak32` in a way that does not reduce
* the security of MuSig (for example, by following Taproot BIP 341).
*
* The tweaking method is the same as `secp256k1_xonly_pubkey_tweak_add`. So in
* the following pseudocode xonly_pubkey_tweak_add_check (absent earlier
* failures) returns 1.
*
* secp256k1_musig_pubkey_agg(..., agg_pk, keyagg_cache, pubkeys, ...)
* secp256k1_musig_pubkey_xonly_tweak_add(..., output_pk, keyagg_cache, tweak32)
* secp256k1_xonly_pubkey_serialize(..., buf, output_pk)
* secp256k1_xonly_pubkey_tweak_add_check(..., buf, ..., agg_pk, tweak32)
*
* This function is required if you want to _sign_ for a tweaked aggregate key.
* If you are only computing a public key but not intending to create a
* signature for it, use `secp256k1_xonly_pubkey_tweak_add` instead.
*
* Returns: 0 if the arguments are invalid, 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. If you
* do not need it, this arg can be NULL.
* In/Out: keyagg_cache: pointer to a `musig_keyagg_cache` struct initialized by
* `musig_pubkey_agg`
* In: tweak32: pointer to a 32-byte tweak. The tweak is valid if it passes
* `secp256k1_ec_seckey_verify` and is not equal to the
* secret key corresponding to the public key represented
* by keyagg_cache or its negation. 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_musig_pubkey_xonly_tweak_add(
const secp256k1_context *ctx,
secp256k1_pubkey *output_pubkey,
secp256k1_musig_keyagg_cache *keyagg_cache,
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
/** Starts a signing session by generating a nonce
*
* This function outputs a secret nonce that will be required for signing and a
* corresponding public nonce that is intended to be sent to other signers.
*
* MuSig differs from regular Schnorr signing in that implementers _must_ take
* special care to not reuse a nonce. This can be ensured by following these rules:
*
* 1. Each call to this function must have a UNIQUE session_secrand32 that must
* NOT BE REUSED in subsequent calls to this function and must be KEPT
* SECRET (even from other signers).
* 2. If you already know the seckey, message or aggregate public key
* cache, they can be optionally provided to derive the nonce and increase
* misuse-resistance. The extra_input32 argument can be used to provide
* additional data that does not repeat in normal scenarios, such as the
* current time.
* 3. Avoid copying (or serializing) the secnonce. This reduces the possibility
* that it is used more than once for signing.
*
* If you don't have access to good randomness for session_secrand32, but you
* have access to a non-repeating counter, then see
* secp256k1_musig_nonce_gen_counter.
*
* Remember that nonce reuse will leak the secret key!
* Note that using the same seckey for multiple MuSig sessions is fine.
*
* Returns: 0 if the arguments are invalid and 1 otherwise
* Args: ctx: pointer to a context object (not secp256k1_context_static)
* Out: secnonce: pointer to a structure to store the secret nonce
* pubnonce: pointer to a structure to store the public nonce
* In/Out:
* session_secrand32: a 32-byte session_secrand32 as explained above. Must be unique to this
* call to secp256k1_musig_nonce_gen and must be uniformly
* random. If the function call is successful, the
* session_secrand32 buffer is invalidated to prevent reuse.
* In:
* seckey: the 32-byte secret key that will later be used for signing, if
* already known (can be NULL)
* pubkey: public key of the signer creating the nonce. The secnonce
* output of this function cannot be used to sign for any
* other public key. While the public key should correspond
* to the provided seckey, a mismatch will not cause the
* function to return 0.
* msg32: the 32-byte message that will later be signed, if already known
* (can be NULL)
* keyagg_cache: pointer to the keyagg_cache that was used to create the aggregate
* (and potentially tweaked) public key if already known
* (can be NULL)
* extra_input32: an optional 32-byte array that is input to the nonce
* derivation function (can be NULL)
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_nonce_gen(
const secp256k1_context *ctx,
secp256k1_musig_secnonce *secnonce,
secp256k1_musig_pubnonce *pubnonce,
unsigned char *session_secrand32,
const unsigned char *seckey,
const secp256k1_pubkey *pubkey,
const unsigned char *msg32,
const secp256k1_musig_keyagg_cache *keyagg_cache,
const unsigned char *extra_input32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(6);
/** Alternative way to generate a nonce and start a signing session
*
* This function outputs a secret nonce that will be required for signing and a
* corresponding public nonce that is intended to be sent to other signers.
*
* This function differs from `secp256k1_musig_nonce_gen` by accepting a
* non-repeating counter value instead of a secret random value. This requires
* that a secret key is provided to `secp256k1_musig_nonce_gen_counter`
* (through the keypair argument), as opposed to `secp256k1_musig_nonce_gen`
* where the seckey argument is optional.
*
* MuSig differs from regular Schnorr signing in that implementers _must_ take
* special care to not reuse a nonce. This can be ensured by following these rules:
*
* 1. The nonrepeating_cnt argument must be a counter value that never repeats,
* i.e., you must never call `secp256k1_musig_nonce_gen_counter` twice with
* the same keypair and nonrepeating_cnt value. For example, this implies
* that if the same keypair is used with `secp256k1_musig_nonce_gen_counter`
* on multiple devices, none of the devices should have the same counter
* value as any other device.
* 2. If the seckey, message or aggregate public key cache is already available
* at this stage, any of these can be optionally provided, in which case
* they will be used in the derivation of the nonce and increase
* misuse-resistance. The extra_input32 argument can be used to provide
* additional data that does not repeat in normal scenarios, such as the
* current time.
* 3. Avoid copying (or serializing) the secnonce. This reduces the possibility
* that it is used more than once for signing.
*
* Remember that nonce reuse will leak the secret key!
* Note that using the same keypair for multiple MuSig sessions is fine.
*
* Returns: 0 if the arguments are invalid and 1 otherwise
* Args: ctx: pointer to a context object (not secp256k1_context_static)
* Out: secnonce: pointer to a structure to store the secret nonce
* pubnonce: pointer to a structure to store the public nonce
* In:
* nonrepeating_cnt: the value of a counter as explained above. Must be
* unique to this call to secp256k1_musig_nonce_gen.
* keypair: keypair of the signer creating the nonce. The secnonce
* output of this function cannot be used to sign for any
* other keypair.
* msg32: the 32-byte message that will later be signed, if already known
* (can be NULL)
* keyagg_cache: pointer to the keyagg_cache that was used to create the aggregate
* (and potentially tweaked) public key if already known
* (can be NULL)
* extra_input32: an optional 32-byte array that is input to the nonce
* derivation function (can be NULL)
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_nonce_gen_counter(
const secp256k1_context *ctx,
secp256k1_musig_secnonce *secnonce,
secp256k1_musig_pubnonce *pubnonce,
uint64_t nonrepeating_cnt,
const secp256k1_keypair *keypair,
const unsigned char *msg32,
const secp256k1_musig_keyagg_cache *keyagg_cache,
const unsigned char *extra_input32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(5);
/** Aggregates the nonces of all signers into a single nonce
*
* This can be done by an untrusted party to reduce the communication
* between signers. Instead of everyone sending nonces to everyone else, there
* can be one party receiving all nonces, aggregating the nonces with this
* function and then sending only the aggregate nonce back to the signers.
*
* If the aggregator does not compute the aggregate nonce correctly, the final
* signature will be invalid.
*
* Returns: 0 if the arguments are invalid, 1 otherwise
* Args: ctx: pointer to a context object
* Out: aggnonce: pointer to an aggregate public nonce object for
* musig_nonce_process
* In: pubnonces: array of pointers to public nonces sent by the
* signers
* n_pubnonces: number of elements in the pubnonces array. Must be
* greater than 0.
*/
SECP256K1_API int secp256k1_musig_nonce_agg(
const secp256k1_context *ctx,
secp256k1_musig_aggnonce *aggnonce,
const secp256k1_musig_pubnonce * const *pubnonces,
size_t n_pubnonces
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Takes the aggregate nonce and creates a session that is required for signing
* and verification of partial signatures.
*
* Returns: 0 if the arguments are invalid, 1 otherwise
* Args: ctx: pointer to a context object
* Out: session: pointer to a struct to store the session
* In: aggnonce: pointer to an aggregate public nonce object that is the
* output of musig_nonce_agg
* msg32: the 32-byte message to sign
* keyagg_cache: pointer to the keyagg_cache that was used to create the
* aggregate (and potentially tweaked) pubkey
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_nonce_process(
const secp256k1_context *ctx,
secp256k1_musig_session *session,
const secp256k1_musig_aggnonce *aggnonce,
const unsigned char *msg32,
const secp256k1_musig_keyagg_cache *keyagg_cache
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5);
/** Produces a partial signature
*
* This function overwrites the given secnonce with zeros and will abort if given a
* secnonce that is all zeros. This is a best effort attempt to protect against nonce
* reuse. However, this is of course easily defeated if the secnonce has been
* copied (or serialized). Remember that nonce reuse will leak the secret key!
*
* For signing to succeed, the secnonce provided to this function must have
* been generated for the provided keypair. This means that when signing for a
* keypair consisting of a seckey and pubkey, the secnonce must have been
* created by calling musig_nonce_gen with that pubkey. Otherwise, the
* illegal_callback is called.
*
* This function does not verify the output partial signature, deviating from
* the BIP 327 specification. It is recommended to verify the output partial
* signature with `secp256k1_musig_partial_sig_verify` to prevent random or
* adversarially provoked computation errors.
*
* Returns: 0 if the arguments are invalid or the provided secnonce has already
* been used for signing, 1 otherwise
* Args: ctx: pointer to a context object
* Out: partial_sig: pointer to struct to store the partial signature
* In/Out: secnonce: pointer to the secnonce struct created in
* musig_nonce_gen that has been never used in a
* partial_sign call before and has been created for the
* keypair
* In: keypair: pointer to keypair to sign the message with
* keyagg_cache: pointer to the keyagg_cache that was output when the
* aggregate public key for this session
* session: pointer to the session that was created with
* musig_nonce_process
*/
SECP256K1_API int secp256k1_musig_partial_sign(
const secp256k1_context *ctx,
secp256k1_musig_partial_sig *partial_sig,
secp256k1_musig_secnonce *secnonce,
const secp256k1_keypair *keypair,
const secp256k1_musig_keyagg_cache *keyagg_cache,
const secp256k1_musig_session *session
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5) SECP256K1_ARG_NONNULL(6);
/** Verifies an individual signer's partial signature
*
* The signature is verified for a specific signing session. In order to avoid
* accidentally verifying a signature from a different or non-existing signing
* session, you must ensure the following:
* 1. The `keyagg_cache` argument is identical to the one used to create the
* `session` with `musig_nonce_process`.
* 2. The `pubkey` argument must be identical to the one sent by the signer
* before aggregating it with `musig_pubkey_agg` to create the
* `keyagg_cache`.
* 3. The `pubnonce` argument must be identical to the one sent by the signer
* before aggregating it with `musig_nonce_agg` and using the result to
* create the `session` with `musig_nonce_process`.
*
* It is not required to call this function in regular MuSig sessions, because
* if any partial signature does not verify, the final signature will not
* verify either, so the problem will be caught. However, this function
* provides the ability to identify which specific partial signature fails
* verification.
*
* Returns: 0 if the arguments are invalid or the partial signature does not
* verify, 1 otherwise
* Args ctx: pointer to a context object
* In: partial_sig: pointer to partial signature to verify, sent by
* the signer associated with `pubnonce` and `pubkey`
* pubnonce: public nonce of the signer in the signing session
* pubkey: public key of the signer in the signing session
* keyagg_cache: pointer to the keyagg_cache that was output when the
* aggregate public key for this signing session
* session: pointer to the session that was created with
* `musig_nonce_process`
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_musig_partial_sig_verify(
const secp256k1_context *ctx,
const secp256k1_musig_partial_sig *partial_sig,
const secp256k1_musig_pubnonce *pubnonce,
const secp256k1_pubkey *pubkey,
const secp256k1_musig_keyagg_cache *keyagg_cache,
const secp256k1_musig_session *session
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5) SECP256K1_ARG_NONNULL(6);
/** Aggregates partial signatures
*
* Returns: 0 if the arguments are invalid, 1 otherwise (which does NOT mean
* the resulting signature verifies).
* Args: ctx: pointer to a context object
* Out: sig64: complete (but possibly invalid) Schnorr signature
* In: session: pointer to the session that was created with
* musig_nonce_process
* partial_sigs: array of pointers to partial signatures to aggregate
* n_sigs: number of elements in the partial_sigs array. Must be
* greater than 0.
*/
SECP256K1_API int secp256k1_musig_partial_sig_agg(
const secp256k1_context *ctx,
unsigned char *sig64,
const secp256k1_musig_session *session,
const secp256k1_musig_partial_sig * const *partial_sigs,
size_t n_sigs
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
#ifdef __cplusplus
}
#endif
#endif

View File

@@ -52,8 +52,8 @@ SECP256K1_API size_t secp256k1_context_preallocated_size(
* in the memory. In simpler words, the prealloc pointer (or any pointer derived
* from it) should not be used during the lifetime of the context object.
*
* Returns: a newly created context object.
* In: prealloc: a pointer to a rewritable contiguous block of memory of
* Returns: pointer to newly created context object.
* In: prealloc: pointer to a rewritable contiguous block of memory of
* size at least secp256k1_context_preallocated_size(flags)
* bytes, as detailed above.
* flags: which parts of the context to initialize.
@@ -72,7 +72,7 @@ SECP256K1_API secp256k1_context *secp256k1_context_preallocated_create(
* caller-provided memory.
*
* Returns: the required size of the caller-provided memory block.
* In: ctx: an existing context to copy.
* In: ctx: pointer to a context to copy.
*/
SECP256K1_API size_t secp256k1_context_preallocated_clone_size(
const secp256k1_context *ctx
@@ -91,9 +91,9 @@ SECP256K1_API size_t secp256k1_context_preallocated_clone_size(
* Cloning secp256k1_context_static is not possible, and should not be emulated by
* the caller (e.g., using memcpy). Create a new context instead.
*
* Returns: a newly created context object.
* Args: ctx: an existing context to copy (not secp256k1_context_static).
* In: prealloc: a pointer to a rewritable contiguous block of memory of
* Returns: pointer to a newly created context object.
* Args: ctx: pointer to a context to copy (not secp256k1_context_static).
* In: prealloc: pointer to a rewritable contiguous block of memory of
* size at least secp256k1_context_preallocated_size(flags)
* bytes, as detailed above.
*/
@@ -118,7 +118,7 @@ SECP256K1_API secp256k1_context *secp256k1_context_preallocated_clone(
* preallocated pointer given to secp256k1_context_preallocated_create or
* secp256k1_context_preallocated_clone.
*
* Args: ctx: an existing context to destroy, constructed using
* Args: ctx: pointer to a context to destroy, constructed using
* secp256k1_context_preallocated_create or
* secp256k1_context_preallocated_clone
* (i.e., not secp256k1_context_static).

View File

@@ -7,7 +7,7 @@
extern "C" {
#endif
/** Opaque data structured that holds a parsed ECDSA signature,
/** Opaque data structure that holds a parsed ECDSA signature,
* supporting pubkey recovery.
*
* The exact representation of data inside is implementation defined and not
@@ -21,16 +21,16 @@ extern "C" {
* recoverability) will have identical representation, so they can be
* memcmp'ed.
*/
typedef struct {
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: a secp256k1 context object
* Out: sig: a pointer to a signature object
* In: input64: a pointer to a 64-byte compact signature
* 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(
@@ -43,9 +43,9 @@ SECP256K1_API int secp256k1_ecdsa_recoverable_signature_parse_compact(
/** Convert a recoverable signature into a normal signature.
*
* Returns: 1
* Args: ctx: a secp256k1 context object.
* Out: sig: a pointer to a normal signature.
* In: sigin: a pointer to a recoverable signature.
* 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,
@@ -56,10 +56,10 @@ SECP256K1_API int secp256k1_ecdsa_recoverable_signature_convert(
/** Serialize an ECDSA signature in compact format (64 bytes + recovery id).
*
* Returns: 1
* Args: ctx: a secp256k1 context object.
* Out: output64: a pointer to a 64-byte array of the compact signature.
* recid: a pointer to an integer to hold the recovery id.
* In: sig: a pointer to an initialized signature object.
* 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,

View File

@@ -61,7 +61,7 @@ typedef int (*secp256k1_nonce_function_hardened)(
* Therefore, to create BIP-340 compliant signatures, algo must be set to
* "BIP0340/nonce" and algolen to 13.
*/
SECP256K1_API_VAR const secp256k1_nonce_function_hardened secp256k1_nonce_function_bip340;
SECP256K1_API const secp256k1_nonce_function_hardened secp256k1_nonce_function_bip340;
/** Data structure that contains additional arguments for schnorrsig_sign_custom.
*
@@ -79,7 +79,7 @@ SECP256K1_API_VAR const secp256k1_nonce_function_hardened secp256k1_nonce_functi
* secp256k1_nonce_function_bip340 is used, then ndata must be a
* pointer to 32-byte auxiliary randomness as per BIP-340.
*/
typedef struct {
typedef struct secp256k1_schnorrsig_extraparams {
unsigned char magic[4];
secp256k1_nonce_function_hardened noncefp;
void *ndata;
@@ -169,11 +169,11 @@ SECP256K1_API int secp256k1_schnorrsig_sign_custom(
*
* Returns: 1: correct signature
* 0: incorrect signature
* Args: ctx: a secp256k1 context object.
* Args: ctx: pointer to a context object.
* In: sig64: pointer to the 64-byte signature to verify.
* msg: the message being verified. Can only be NULL if msglen is 0.
* msglen: length of the message
* pubkey: pointer to an x-only public key to verify with (cannot be NULL)
* pubkey: pointer to an x-only public key to verify with
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_schnorrsig_verify(
const secp256k1_context *ctx,