secp256k1.h

Go to the documentation of this file.

#ifndef SECP256K1_H
#define SECP256K1_H

#ifdef __cplusplus
extern "C" {
#endif

#include <stddef.h>

typedef struct secp256k1_context_struct secp256k1_context;

typedef struct secp256k1_pubkey {
    unsigned char data[64];
} secp256k1_pubkey;

typedef struct secp256k1_ecdsa_signature {
    unsigned char data[64];
} secp256k1_ecdsa_signature;

typedef int (*secp256k1_nonce_function)(
    unsigned char *nonce32,
    const unsigned char *msg32,
    const unsigned char *key32,
    const unsigned char *algo16,
    void *data,
    unsigned int attempt
);

# if !defined(SECP256K1_GNUC_PREREQ)
#  if defined(__GNUC__)&&defined(__GNUC_MINOR__)
#   define SECP256K1_GNUC_PREREQ(_maj,_min) \
 ((__GNUC__<<16)+__GNUC_MINOR__>=((_maj)<<16)+(_min))
#  else
#   define SECP256K1_GNUC_PREREQ(_maj,_min) 0
#  endif
# endif

/*  When this header is used at build-time the SECP256K1_BUILD define needs to be set
 *  to correctly setup export attributes and nullness checks.  This is normally done
 *  by secp256k1.c but to guard against this header being included before secp256k1.c
 *  has had a chance to set the define (e.g. via test harnesses that just includes
 *  secp256k1.c) we set SECP256K1_NO_BUILD when this header is processed without the
 *  BUILD define so this condition can be caught.
 */
#ifndef SECP256K1_BUILD
# define SECP256K1_NO_BUILD
#endif

/* Symbol visibility. */
#if !defined(SECP256K1_API) && defined(SECP256K1_NO_API_VISIBILITY_ATTRIBUTES)
     /* The user has requested that we don't specify visibility attributes in
      * the public API.
      *
      * Since all our non-API declarations use the static qualifier, this means
      * that the user can use -fvisibility=<value> to set the visibility of the
      * API symbols. For instance, -fvisibility=hidden can be useful *even for
      * the API symbols*, e.g., when building a static library which is linked
      * into a shared library, and the latter should not re-export the
      * libsecp256k1 API.
      *
      * While visibility is a concept that applies only to shared libraries,
      * setting visibility will still make a difference when building a static
      * library: the visibility settings will be stored in the static library,
      * solely for the potential case that the static library will be linked into
      * a shared library. In that case, the stored visibility settings will
      * resurface and be honored for the shared library. */
#    define SECP256K1_API extern
#endif
#if !defined(SECP256K1_API)
#    if defined(SECP256K1_BUILD)
         /* On Windows, assume a shared library only if explicitly requested.
          *   1. If using Libtool, it defines DLL_EXPORT automatically.
          *   2. In other cases, SECP256K1_DLL_EXPORT must be defined. */
#        if defined(_WIN32) && (defined(SECP256K1_DLL_EXPORT) || defined(DLL_EXPORT))
             /* 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 . */
#            define SECP256K1_API extern __declspec(dllexport)
         /* Avoid __attribute__ ((visibility("default"))) on Windows to get rid
          * of warnings when compiling with -flto due to a bug in GCC, see
          * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116478 . */
#        elif !defined(_WIN32) && defined (__GNUC__) && (__GNUC__ >= 4)
#            define SECP256K1_API extern __attribute__ ((visibility("default")))
#        else
#            define SECP256K1_API extern
#        endif
#    else
         /* On Windows, SECP256K1_STATIC must be defined when consuming
          * libsecp256k1 as a static library. Note that SECP256K1_STATIC is a
          * "consumer-only" macro, and it has no meaning when building
          * libsecp256k1. */
#        if defined(_WIN32) && !defined(SECP256K1_STATIC)
#            define SECP256K1_API extern __declspec(dllimport)
#        else
#            define SECP256K1_API extern
#        endif
#    endif
#endif

/* Warning attributes
 * NONNULL is not used if SECP256K1_BUILD is set to avoid the compiler optimizing out
 * some paranoid null checks. */
# if defined(__GNUC__) && SECP256K1_GNUC_PREREQ(3, 4)
#  define SECP256K1_WARN_UNUSED_RESULT __attribute__ ((__warn_unused_result__))
# else
#  define SECP256K1_WARN_UNUSED_RESULT
# endif
# if !defined(SECP256K1_BUILD) && defined(__GNUC__) && SECP256K1_GNUC_PREREQ(3, 4)
#  define SECP256K1_ARG_NONNULL(_x)  __attribute__ ((__nonnull__(_x)))
# else
#  define SECP256K1_ARG_NONNULL(_x)
# endif

/* Attribute for marking functions, types, and variables as deprecated */
#if !defined(SECP256K1_BUILD) && defined(__has_attribute)
# if __has_attribute(__deprecated__)
#  define SECP256K1_DEPRECATED(_msg) __attribute__ ((__deprecated__(_msg)))
# else
#  define SECP256K1_DEPRECATED(_msg)
# endif
#else
# define SECP256K1_DEPRECATED(_msg)
#endif

/* All flags' lower 8 bits indicate what they're for. Do not use directly. */
#define SECP256K1_FLAGS_TYPE_MASK ((1 << 8) - 1)
#define SECP256K1_FLAGS_TYPE_CONTEXT (1 << 0)
#define SECP256K1_FLAGS_TYPE_COMPRESSION (1 << 1)
/* The higher bits contain the actual data. Do not use directly. */
#define SECP256K1_FLAGS_BIT_CONTEXT_VERIFY (1 << 8)
#define SECP256K1_FLAGS_BIT_CONTEXT_SIGN (1 << 9)
#define SECP256K1_FLAGS_BIT_CONTEXT_DECLASSIFY (1 << 10)
#define SECP256K1_FLAGS_BIT_COMPRESSION (1 << 8)

#define SECP256K1_CONTEXT_NONE (SECP256K1_FLAGS_TYPE_CONTEXT)

#define SECP256K1_CONTEXT_VERIFY (SECP256K1_FLAGS_TYPE_CONTEXT | SECP256K1_FLAGS_BIT_CONTEXT_VERIFY)
#define SECP256K1_CONTEXT_SIGN (SECP256K1_FLAGS_TYPE_CONTEXT | SECP256K1_FLAGS_BIT_CONTEXT_SIGN)

/* Testing flag. Do not use. */
#define SECP256K1_CONTEXT_DECLASSIFY (SECP256K1_FLAGS_TYPE_CONTEXT | SECP256K1_FLAGS_BIT_CONTEXT_DECLASSIFY)

#define SECP256K1_EC_COMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION | SECP256K1_FLAGS_BIT_COMPRESSION)
#define SECP256K1_EC_UNCOMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION)

#define SECP256K1_TAG_PUBKEY_EVEN 0x02
#define SECP256K1_TAG_PUBKEY_ODD 0x03
#define SECP256K1_TAG_PUBKEY_UNCOMPRESSED 0x04
#define SECP256K1_TAG_PUBKEY_HYBRID_EVEN 0x06
#define SECP256K1_TAG_PUBKEY_HYBRID_ODD 0x07

SECP256K1_API const secp256k1_context * const secp256k1_context_static;

SECP256K1_API const secp256k1_context * const secp256k1_context_no_precomp
SECP256K1_DEPRECATED("Use secp256k1_context_static instead");

SECP256K1_API void secp256k1_selftest(void);


SECP256K1_API secp256k1_context *secp256k1_context_create(
    unsigned int flags
) SECP256K1_WARN_UNUSED_RESULT;

SECP256K1_API secp256k1_context *secp256k1_context_clone(
    const secp256k1_context *ctx
) SECP256K1_ARG_NONNULL(1) SECP256K1_WARN_UNUSED_RESULT;

SECP256K1_API void secp256k1_context_destroy(
    secp256k1_context *ctx
) SECP256K1_ARG_NONNULL(1);

SECP256K1_API void secp256k1_context_set_illegal_callback(
    secp256k1_context *ctx,
    void (*fun)(const char *message, void *data),
    const void *data
) SECP256K1_ARG_NONNULL(1);

SECP256K1_API void secp256k1_context_set_error_callback(
    secp256k1_context *ctx,
    void (*fun)(const char *message, void *data),
    const void *data
) SECP256K1_ARG_NONNULL(1);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_parse(
    const secp256k1_context *ctx,
    secp256k1_pubkey *pubkey,
    const unsigned char *input,
    size_t inputlen
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API int secp256k1_ec_pubkey_serialize(
    const secp256k1_context *ctx,
    unsigned char *output,
    size_t *outputlen,
    const secp256k1_pubkey *pubkey,
    unsigned int flags
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_cmp(
    const secp256k1_context *ctx,
    const secp256k1_pubkey *pubkey1,
    const secp256k1_pubkey *pubkey2
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

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);

SECP256K1_API int secp256k1_ecdsa_signature_parse_compact(
    const secp256k1_context *ctx,
    secp256k1_ecdsa_signature *sig,
    const unsigned char *input64
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API int secp256k1_ecdsa_signature_parse_der(
    const secp256k1_context *ctx,
    secp256k1_ecdsa_signature *sig,
    const unsigned char *input,
    size_t inputlen
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API int secp256k1_ecdsa_signature_serialize_der(
    const secp256k1_context *ctx,
    unsigned char *output,
    size_t *outputlen,
    const secp256k1_ecdsa_signature *sig
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);

SECP256K1_API int secp256k1_ecdsa_signature_serialize_compact(
    const secp256k1_context *ctx,
    unsigned char *output64,
    const secp256k1_ecdsa_signature *sig
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
    const secp256k1_context *ctx,
    const secp256k1_ecdsa_signature *sig,
    const unsigned char *msghash32,
    const secp256k1_pubkey *pubkey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);

SECP256K1_API int secp256k1_ecdsa_signature_normalize(
    const secp256k1_context *ctx,
    secp256k1_ecdsa_signature *sigout,
    const secp256k1_ecdsa_signature *sigin
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(3);

SECP256K1_API const secp256k1_nonce_function secp256k1_nonce_function_rfc6979;

SECP256K1_API const secp256k1_nonce_function secp256k1_nonce_function_default;

SECP256K1_API int secp256k1_ecdsa_sign(
    const secp256k1_context *ctx,
    secp256k1_ecdsa_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);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_verify(
    const secp256k1_context *ctx,
    const unsigned char *seckey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_create(
    const secp256k1_context *ctx,
    secp256k1_pubkey *pubkey,
    const unsigned char *seckey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_negate(
    const secp256k1_context *ctx,
    unsigned char *seckey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2);

SECP256K1_API int secp256k1_ec_pubkey_negate(
    const secp256k1_context *ctx,
    secp256k1_pubkey *pubkey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_add(
    const secp256k1_context *ctx,
    unsigned char *seckey,
    const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add(
    const secp256k1_context *ctx,
    secp256k1_pubkey *pubkey,
    const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_tweak_mul(
    const secp256k1_context *ctx,
    unsigned char *seckey,
    const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_mul(
    const secp256k1_context *ctx,
    secp256k1_pubkey *pubkey,
    const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_context_randomize(
    secp256k1_context *ctx,
    const unsigned char *seed32
) SECP256K1_ARG_NONNULL(1);

SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_combine(
    const secp256k1_context *ctx,
    secp256k1_pubkey *out,
    const secp256k1_pubkey * const *ins,
    size_t n
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);

SECP256K1_API int secp256k1_tagged_sha256(
    const secp256k1_context *ctx,
    unsigned char *hash32,
    const unsigned char *tag,
    size_t taglen,
    const unsigned char *msg,
    size_t msglen
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(5);

#ifdef __cplusplus
}
#endif

#endif /* SECP256K1_H */