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-rw-r--r--src/secp256k1/include/secp256k1.h696
-rw-r--r--src/secp256k1/include/secp256k1_ecdh.h31
-rw-r--r--src/secp256k1/include/secp256k1_recovery.h110
-rw-r--r--src/secp256k1/include/secp256k1_schnorr.h173
4 files changed, 780 insertions, 230 deletions
diff --git a/src/secp256k1/include/secp256k1.h b/src/secp256k1/include/secp256k1.h
index 06afd4c65b..7145dbcc54 100644
--- a/src/secp256k1/include/secp256k1.h
+++ b/src/secp256k1/include/secp256k1.h
@@ -5,6 +5,99 @@
extern "C" {
# endif
+#include <stddef.h>
+
+/* These rules specify the order of arguments in API calls:
+ *
+ * 1. Context pointers go first, followed by output arguments, combined
+ * output/input arguments, and finally input-only arguments.
+ * 2. Array lengths always immediately the follow the argument whose length
+ * they describe, even if this violates rule 1.
+ * 3. Within the OUT/OUTIN/IN groups, pointers to data that is typically generated
+ * later go first. This means: signatures, public nonces, private nonces,
+ * messages, public keys, secret keys, tweaks.
+ * 4. Arguments that are not data pointers go last, from more complex to less
+ * complex: function pointers, algorithm names, messages, void pointers,
+ * counts, flags, booleans.
+ * 5. Opaque data pointers follow the function pointer they are to be passed to.
+ */
+
+/** Opaque data structure that holds context information (precomputed tables etc.).
+ *
+ * The purpose of context structures is to cache large precomputed data tables
+ * that are expensive to construct, and also to maintain the randomization data
+ * for blinding.
+ *
+ * Do not create a new context object for each operation, as construction is
+ * far slower than all other API calls (~100 times slower than an ECDSA
+ * verification).
+ *
+ * A constructed context can safely be used from multiple threads
+ * simultaneously, but API call that take a non-const pointer to a context
+ * need exclusive access to it. In particular this is the case for
+ * secp256k1_context_destroy and secp256k1_context_randomize.
+ *
+ * Regarding randomization, either do it once at creation time (in which case
+ * you do not need any locking for the other calls), or use a read-write lock.
+ */
+typedef struct secp256k1_context_struct secp256k1_context;
+
+/** Opaque data structure that holds a parsed and valid 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 64 bytes in size, and can be safely copied/moved.
+ * If you need to convert to a format suitable for storage or transmission, use
+ * secp256k1_ec_pubkey_serialize and secp256k1_ec_pubkey_parse.
+ *
+ * Furthermore, it is guaranteed that identical public keys (ignoring
+ * compression) will have identical representation, so they can be memcmp'ed.
+ */
+typedef struct {
+ unsigned char data[64];
+} secp256k1_pubkey;
+
+/** Opaque data structured 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
+ * 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 or transmission, use
+ * the secp256k1_ecdsa_signature_serialize_* and
+ * secp256k1_ecdsa_signature_serialize_* functions.
+ *
+ * Furthermore, it is guaranteed to identical signatures will have identical
+ * representation, so they can be memcmp'ed.
+ */
+typedef struct {
+ unsigned char data[64];
+} secp256k1_ecdsa_signature;
+
+/** A pointer to a function to deterministically generate a nonce.
+ *
+ * Returns: 1 if a nonce was successfully generated. 0 will cause signing to fail.
+ * Out: nonce32: pointer to a 32-byte array to be filled by the function.
+ * In: msg32: the 32-byte message hash being verified (will not be NULL)
+ * key32: pointer to a 32-byte secret key (will not be NULL)
+ * algo16: pointer to a 16-byte array describing the signature
+ * algorithm (will be NULL for ECDSA for compatibility).
+ * data: Arbitrary data pointer that is passed through.
+ * attempt: how many iterations we have tried to find a nonce.
+ * This will almost always be 0, but different attempt values
+ * are required to result in a different nonce.
+ *
+ * Except for test cases, this function should compute some cryptographic hash of
+ * the message, the algorithm, the key and the attempt.
+ */
+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) \
@@ -26,6 +119,20 @@ extern "C" {
# define SECP256K1_INLINE inline
# endif
+#ifndef SECP256K1_API
+# if defined(_WIN32)
+# ifdef SECP256K1_BUILD
+# define SECP256K1_API __declspec(dllexport)
+# else
+# define SECP256K1_API
+# endif
+# elif defined(__GNUC__) && defined(SECP256K1_BUILD)
+# define SECP256K1_API __attribute__ ((visibility ("default")))
+# else
+# define SECP256K1_API
+# endif
+#endif
+
/**Warning attributes
* NONNULL is not used if SECP256K1_BUILD is set to avoid the compiler optimizing out
* some paranoid null checks. */
@@ -40,305 +147,434 @@ extern "C" {
# define SECP256K1_ARG_NONNULL(_x)
# endif
-/** Opaque data structure that holds context information (precomputed tables etc.).
- * Only functions that take a pointer to a non-const context require exclusive
- * access to it. Multiple functions that take a pointer to a const context may
- * run simultaneously.
- */
-typedef struct secp256k1_context_struct secp256k1_context_t;
+/** 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_COMPRESSION (1 << 8)
/** Flags to pass to secp256k1_context_create. */
-# define SECP256K1_CONTEXT_VERIFY (1 << 0)
-# define SECP256K1_CONTEXT_SIGN (1 << 1)
+#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)
+#define SECP256K1_CONTEXT_NONE (SECP256K1_FLAGS_TYPE_CONTEXT)
+
+/** Flag to pass to secp256k1_ec_pubkey_serialize and secp256k1_ec_privkey_export. */
+#define SECP256K1_EC_COMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION | SECP256K1_FLAGS_BIT_COMPRESSION)
+#define SECP256K1_EC_UNCOMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION)
/** Create a secp256k1 context object.
+ *
* Returns: a newly created context object.
* In: flags: which parts of the context to initialize.
*/
-secp256k1_context_t* secp256k1_context_create(
- int flags
+SECP256K1_API secp256k1_context* secp256k1_context_create(
+ unsigned int flags
) SECP256K1_WARN_UNUSED_RESULT;
/** Copies a secp256k1 context object.
+ *
* Returns: a newly created context object.
- * In: ctx: an existing context to copy
+ * Args: ctx: an existing context to copy (cannot be NULL)
*/
-secp256k1_context_t* secp256k1_context_clone(
- const secp256k1_context_t* ctx
-) SECP256K1_WARN_UNUSED_RESULT;
+SECP256K1_API secp256k1_context* secp256k1_context_clone(
+ const secp256k1_context* ctx
+) SECP256K1_ARG_NONNULL(1) SECP256K1_WARN_UNUSED_RESULT;
/** Destroy a secp256k1 context object.
+ *
* The context pointer may not be used afterwards.
+ * Args: ctx: an existing context to destroy (cannot be NULL)
+ */
+SECP256K1_API void secp256k1_context_destroy(
+ secp256k1_context* ctx
+);
+
+/** Set a callback function to be called when an illegal argument is passed to
+ * an API call. It will only trigger for violations that are mentioned
+ * explicitly in the header.
+ *
+ * The philosophy is that these shouldn't be dealt with through a
+ * specific return value, as calling code should not have branches to deal with
+ * the case that this code itself is broken.
+ *
+ * On the other hand, during debug stage, one would want to be informed about
+ * such mistakes, and the default (crashing) may be inadvisable.
+ * When this callback is triggered, the API function called is guaranteed not
+ * to cause a crash, though its return value and output arguments are
+ * undefined.
+ *
+ * Args: ctx: an existing context object (cannot be NULL)
+ * In: fun: a pointer to a function to call when an illegal argument is
+ * passed to the API, taking a message and an opaque pointer
+ * (NULL restores a default handler that calls abort).
+ * data: the opaque pointer to pass to fun above.
*/
-void secp256k1_context_destroy(
- secp256k1_context_t* ctx
+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);
+/** Set a callback function to be called when an internal consistency check
+ * fails. The default is crashing.
+ *
+ * This can only trigger in case of a hardware failure, miscompilation,
+ * memory corruption, serious bug in the library, or other error would can
+ * otherwise result in undefined behaviour. It will not trigger due to mere
+ * incorrect usage of the API (see secp256k1_context_set_illegal_callback
+ * for that). After this callback returns, anything may happen, including
+ * crashing.
+ *
+ * Args: ctx: an existing context object (cannot be NULL)
+ * In: fun: a pointer to a function to call when an internal error occurs,
+ * taking a message and an opaque pointer (NULL restores a default
+ * handler that calls abort).
+ * data: the opaque pointer to pass to fun above.
+ */
+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);
+
+/** 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.
+ * 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
+ * inputlen: length of the array pointed to by input
+ *
+ * This function supports parsing compressed (33 bytes, header byte 0x02 or
+ * 0x03), uncompressed (65 bytes, header byte 0x04), or hybrid (65 bytes, header
+ * byte 0x06 or 0x07) format public keys.
+ */
+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);
+
+/** 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
+ * compressed==1) byte array to place the serialized key
+ * in.
+ * In/Out: outputlen: a 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
+ * initialized public key.
+ * flags: SECP256K1_EC_COMPRESSED if serialization should be in
+ * compressed format, otherwise SECP256K1_EC_UNCOMPRESSED.
+ */
+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);
+
+/** 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
+ *
+ * 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
+ * encoding is invalid. R and S with value 0 are allowed in the encoding.
+ *
+ * After the call, sig will always be initialized. If parsing failed or R or
+ * S are zero, the resulting sig value is guaranteed to fail validation for any
+ * message and public key.
+ */
+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);
+
+/** 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
+ * inputlen: the length of the array pointed to be input
+ *
+ * This function will accept any valid DER encoded signature, even if the
+ * encoded numbers are out of range.
+ *
+ * After the call, sig will always be initialized. If parsing failed or the
+ * encoded numbers are out of range, signature validation with it is
+ * guaranteed to fail for every message and public key.
+ */
+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);
+
+/** 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
+ * 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
+ */
+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);
+
+/** 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
+ *
+ * See secp256k1_ecdsa_signature_parse_compact for details about the encoding.
+ */
+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);
+
/** Verify an ECDSA signature.
+ *
* Returns: 1: correct signature
- * 0: incorrect signature
- * -1: invalid public key
- * -2: invalid signature
- * In: ctx: a secp256k1 context object, initialized for verification.
+ * 0: incorrect or unparseable signature
+ * Args: ctx: a secp256k1 context object, initialized for verification.
+ * In: sig: the signature being verified (cannot be NULL)
* msg32: the 32-byte message hash being verified (cannot be NULL)
- * sig: the signature being verified (cannot be NULL)
- * siglen: the length of the signature
- * pubkey: the public key to verify with (cannot be NULL)
- * pubkeylen: the length of pubkey
+ * pubkey: pointer to an initialized public key to verify with (cannot be NULL)
+ *
+ * To avoid accepting malleable signatures, only ECDSA signatures in lower-S
+ * form are accepted.
+ *
+ * If you need to accept ECDSA signatures from sources that do not obey this
+ * rule, apply secp256k1_ecdsa_signature_normalize to the signature prior to
+ * validation, but be aware that doing so results in malleable signatures.
+ *
+ * For details, see the comments for that function.
*/
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
- const secp256k1_context_t* ctx,
- const unsigned char *msg32,
- const unsigned char *sig,
- int siglen,
- const unsigned char *pubkey,
- int pubkeylen
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(5);
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
+ const secp256k1_context* ctx,
+ const secp256k1_ecdsa_signature *sig,
+ const unsigned char *msg32,
+ const secp256k1_pubkey *pubkey
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
-/** A pointer to a function to deterministically generate a nonce.
- * Returns: 1 if a nonce was successfully generated. 0 will cause signing to fail.
- * In: msg32: the 32-byte message hash being verified (will not be NULL)
- * key32: pointer to a 32-byte secret key (will not be NULL)
- * attempt: how many iterations we have tried to find a nonce.
- * This will almost always be 0, but different attempt values
- * are required to result in a different nonce.
- * data: Arbitrary data pointer that is passed through.
- * Out: nonce32: pointer to a 32-byte array to be filled by the function.
- * Except for test cases, this function should compute some cryptographic hash of
- * the message, the key and the attempt.
+/** 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,
+ * 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 (cannot be NULL,
+ * 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
+ * is done by negating the S value modulo the order of the curve, 'flipping'
+ * the sign of the random point R which is not included in the signature.
+ *
+ * Forgery of the same message isn't universally problematic, but in systems
+ * where message malleability or uniqueness of signatures is important this can
+ * cause issues. This forgery can be blocked by all verifiers forcing signers
+ * to use a normalized form.
+ *
+ * The lower-S form reduces the size of signatures slightly on average when
+ * variable length encodings (such as DER) are used and is cheap to verify,
+ * making it a good choice. Security of always using lower-S is assured because
+ * anyone can trivially modify a signature after the fact to enforce this
+ * property anyway.
+ *
+ * The lower S value is always between 0x1 and
+ * 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,
+ * inclusive.
+ *
+ * No other forms of ECDSA malleability are known and none seem likely, but
+ * there is no formal proof that ECDSA, even with this additional restriction,
+ * is free of other malleability. Commonly used serialization schemes will also
+ * accept various non-unique encodings, so care should be taken when this
+ * property is required for an application.
+ *
+ * The secp256k1_ecdsa_sign function will by default create signatures in the
+ * lower-S form, and secp256k1_ecdsa_verify will not accept others. In case
+ * signatures come from a system that cannot enforce this property,
+ * secp256k1_ecdsa_signature_normalize must be called before verification.
*/
-typedef int (*secp256k1_nonce_function_t)(
- unsigned char *nonce32,
- const unsigned char *msg32,
- const unsigned char *key32,
- unsigned int attempt,
- const void *data
-);
+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);
/** An implementation of RFC6979 (using HMAC-SHA256) as nonce generation function.
* If a data pointer is passed, it is assumed to be a pointer to 32 bytes of
* extra entropy.
*/
-extern const secp256k1_nonce_function_t secp256k1_nonce_function_rfc6979;
+SECP256K1_API extern const secp256k1_nonce_function secp256k1_nonce_function_rfc6979;
/** A default safe nonce generation function (currently equal to secp256k1_nonce_function_rfc6979). */
-extern const secp256k1_nonce_function_t secp256k1_nonce_function_default;
-
+SECP256K1_API extern const secp256k1_nonce_function secp256k1_nonce_function_default;
/** Create an ECDSA signature.
+ *
* Returns: 1: signature created
- * 0: the nonce generation function failed, the private key was invalid, or there is not
- * enough space in the signature (as indicated by siglen).
- * In: ctx: pointer to a context object, initialized for signing (cannot be NULL)
- * msg32: the 32-byte message hash being signed (cannot be NULL)
- * seckey: pointer to a 32-byte secret key (cannot be NULL)
- * noncefp:pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used
- * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL)
+ * 0: the nonce generation function failed, or the private key was invalid.
+ * Args: ctx: pointer to a context object, initialized for signing (cannot be NULL)
* Out: sig: pointer to an array where the signature will be placed (cannot be NULL)
- * In/Out: siglen: pointer to an int with the length of sig, which will be updated
- * to contain the actual signature length (<=72).
- *
- * The sig always has an s value in the lower half of the range (From 0x1
- * to 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,
- * inclusive), unlike many other implementations.
- * With ECDSA a third-party can can forge a second distinct signature
- * of the same message given a single initial signature without knowing
- * the key by setting s to its additive inverse mod-order, 'flipping' the
- * sign of the random point R which is not included in the signature.
- * Since the forgery is of the same message this isn't universally
- * problematic, but in systems where message malleability or uniqueness
- * of signatures is important this can cause issues. This forgery can be
- * blocked by all verifiers forcing signers to use a canonical form. The
- * lower-S form reduces the size of signatures slightly on average when
- * variable length encodings (such as DER) are used and is cheap to
- * verify, making it a good choice. Security of always using lower-S is
- * assured because anyone can trivially modify a signature after the
- * fact to enforce this property. Adjusting it inside the signing
- * function avoids the need to re-serialize or have curve specific
- * constants outside of the library. By always using a canonical form
- * even in applications where it isn't needed it becomes possible to
- * impose a requirement later if a need is discovered.
- * No other forms of ECDSA malleability are known and none seem likely,
- * but there is no formal proof that ECDSA, even with this additional
- * restriction, is free of other malleability. Commonly used serialization
- * schemes will also accept various non-unique encodings, so care should
- * be taken when this property is required for an application.
- */
-int secp256k1_ecdsa_sign(
- const secp256k1_context_t* ctx,
- const unsigned char *msg32,
- unsigned char *sig,
- int *siglen,
- const unsigned char *seckey,
- secp256k1_nonce_function_t noncefp,
- const void *ndata
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5);
-
-/** Create a compact ECDSA signature (64 byte + recovery id).
- * Returns: 1: signature created
- * 0: the nonce generation function failed, or the secret key was invalid.
- * In: ctx: pointer to a context object, initialized for signing (cannot be NULL)
- * msg32: the 32-byte message hash being signed (cannot be NULL)
+ * In: msg32: the 32-byte message hash being signed (cannot be NULL)
* seckey: pointer to a 32-byte secret key (cannot be NULL)
* noncefp:pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used
* ndata: pointer to arbitrary data used by the nonce generation function (can be NULL)
- * Out: sig: pointer to a 64-byte array where the signature will be placed (cannot be NULL)
- * In case 0 is returned, the returned signature length will be zero.
- * recid: pointer to an int, which will be updated to contain the recovery id (can be NULL)
+ *
+ * The created signature is always in lower-S form. See
+ * secp256k1_ecdsa_signature_normalize for more details.
*/
-int secp256k1_ecdsa_sign_compact(
- const secp256k1_context_t* ctx,
- const unsigned char *msg32,
- unsigned char *sig64,
- const unsigned char *seckey,
- secp256k1_nonce_function_t noncefp,
- const void *ndata,
- int *recid
+SECP256K1_API int secp256k1_ecdsa_sign(
+ const secp256k1_context* ctx,
+ secp256k1_ecdsa_signature *sig,
+ const unsigned char *msg32,
+ const unsigned char *seckey,
+ secp256k1_nonce_function noncefp,
+ const void *ndata
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
-/** Recover an ECDSA public key from a compact signature.
- * Returns: 1: public key successfully recovered (which guarantees a correct signature).
- * 0: otherwise.
- * In: ctx: pointer to a context object, initialized for verification (cannot be NULL)
- * msg32: the 32-byte message hash assumed to be signed (cannot be NULL)
- * sig64: signature as 64 byte array (cannot be NULL)
- * compressed: whether to recover a compressed or uncompressed pubkey
- * recid: the recovery id (0-3, as returned by ecdsa_sign_compact)
- * Out: pubkey: pointer to a 33 or 65 byte array to put the pubkey (cannot be NULL)
- * pubkeylen: pointer to an int that will contain the pubkey length (cannot be NULL)
- */
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_recover_compact(
- const secp256k1_context_t* ctx,
- const unsigned char *msg32,
- const unsigned char *sig64,
- unsigned char *pubkey,
- int *pubkeylen,
- int compressed,
- int recid
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5);
-
/** Verify an ECDSA secret key.
+ *
* Returns: 1: secret key is valid
* 0: secret key is invalid
- * In: ctx: pointer to a context object (cannot be NULL)
- * seckey: pointer to a 32-byte secret key (cannot be NULL)
+ * Args: ctx: pointer to a context object (cannot be NULL)
+ * In: seckey: pointer to a 32-byte secret key (cannot be NULL)
*/
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_verify(
- const secp256k1_context_t* ctx,
- const unsigned char *seckey
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2);
-
-/** Just validate a public key.
- * Returns: 1: public key is valid
- * 0: public key is invalid
- * In: ctx: pointer to a context object (cannot be NULL)
- * pubkey: pointer to a 33-byte or 65-byte public key (cannot be NULL).
- * pubkeylen: length of pubkey
- */
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_verify(
- const secp256k1_context_t* ctx,
- const unsigned char *pubkey,
- int pubkeylen
+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);
/** Compute the public key for a secret key.
- * In: ctx: pointer to a context object, initialized for signing (cannot be NULL)
- * compressed: whether the computed public key should be compressed
- * seckey: pointer to a 32-byte private key (cannot be NULL)
- * Out: pubkey: pointer to a 33-byte (if compressed) or 65-byte (if uncompressed)
- * area to store the public key (cannot be NULL)
- * pubkeylen: pointer to int that will be updated to contains the pubkey's
- * length (cannot be NULL)
+ *
* Returns: 1: secret was valid, public key stores
* 0: secret was invalid, try again
+ * Args: ctx: pointer to a context object, initialized for signing (cannot be NULL)
+ * Out: pubkey: pointer to the created public key (cannot be NULL)
+ * In: seckey: pointer to a 32-byte private key (cannot be NULL)
*/
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_create(
- const secp256k1_context_t* ctx,
- unsigned char *pubkey,
- int *pubkeylen,
- const unsigned char *seckey,
- int compressed
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
-
-/** Decompress a public key.
- * In: ctx: pointer to a context object (cannot be NULL)
- * In/Out: pubkey: pointer to a 65-byte array to put the decompressed public key.
- * It must contain a 33-byte or 65-byte public key already (cannot be NULL)
- * pubkeylen: pointer to the size of the public key pointed to by pubkey (cannot be NULL)
- * It will be updated to reflect the new size.
- * Returns: 0: pubkey was invalid
- * 1: pubkey was valid, and was replaced with its decompressed version
- */
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_decompress(
- const secp256k1_context_t* ctx,
- unsigned char *pubkey,
- int *pubkeylen
+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);
-/** Export a private key in DER format.
- * In: ctx: pointer to a context object, initialized for signing (cannot be NULL)
+/** Tweak a private key by adding tweak to it.
+ * Returns: 0 if the tweak was out of range (chance of around 1 in 2^128 for
+ * uniformly random 32-byte arrays, or if the resulting private key
+ * would be invalid (only when the tweak is the complement of the
+ * private key). 1 otherwise.
+ * Args: ctx: pointer to a context object (cannot be NULL).
+ * In/Out: seckey: pointer to a 32-byte private key.
+ * In: tweak: pointer to a 32-byte tweak.
*/
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_export(
- const secp256k1_context_t* ctx,
- const unsigned char *seckey,
- unsigned char *privkey,
- int *privkeylen,
- int compressed
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
-
-/** Import a private key in DER format. */
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_import(
- const secp256k1_context_t* ctx,
- unsigned char *seckey,
- const unsigned char *privkey,
- int privkeylen
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add(
+ const secp256k1_context* ctx,
+ unsigned char *seckey,
+ const unsigned char *tweak
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
-/** Tweak a private key by adding tweak to it. */
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_add(
- const secp256k1_context_t* ctx,
- unsigned char *seckey,
- const unsigned char *tweak
+/** Tweak a public key by adding tweak times the generator to it.
+ * Returns: 0 if the tweak was out of range (chance of around 1 in 2^128 for
+ * uniformly random 32-byte arrays, or if the resulting public key
+ * would be invalid (only when the tweak is the complement of the
+ * corresponding private key). 1 otherwise.
+ * Args: ctx: pointer to a context object initialized for validation
+ * (cannot be NULL).
+ * In/Out: pubkey: pointer to a public key object.
+ * In: tweak: pointer to a 32-byte tweak.
+ */
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add(
+ const secp256k1_context* ctx,
+ secp256k1_pubkey *pubkey,
+ const unsigned char *tweak
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
-/** Tweak a public key by adding tweak times the generator to it.
- * In: ctx: pointer to a context object, initialized for verification (cannot be NULL)
+/** Tweak a private key by multiplying it by a tweak.
+ * Returns: 0 if the tweak was out of range (chance of around 1 in 2^128 for
+ * uniformly random 32-byte arrays, or equal to zero. 1 otherwise.
+ * Args: ctx: pointer to a context object (cannot be NULL).
+ * In/Out: seckey: pointer to a 32-byte private key.
+ * In: tweak: pointer to a 32-byte tweak.
*/
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_add(
- const secp256k1_context_t* ctx,
- unsigned char *pubkey,
- int pubkeylen,
- const unsigned char *tweak
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
-
-/** Tweak a private key by multiplying it with tweak. */
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul(
- const secp256k1_context_t* ctx,
- unsigned char *seckey,
- const unsigned char *tweak
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_tweak_mul(
+ const secp256k1_context* ctx,
+ unsigned char *seckey,
+ const unsigned char *tweak
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
-/** Tweak a public key by multiplying it with tweak.
- * In: ctx: pointer to a context object, initialized for verification (cannot be NULL)
+/** Tweak a public key by multiplying it by a tweak value.
+ * Returns: 0 if the tweak was out of range (chance of around 1 in 2^128 for
+ * uniformly random 32-byte arrays, or equal to zero. 1 otherwise.
+ * Args: ctx: pointer to a context object initialized for validation
+ * (cannot be NULL).
+ * In/Out: pubkey: pointer to a public key obkect.
+ * In: tweak: pointer to a 32-byte tweak.
*/
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_mul(
- const secp256k1_context_t* ctx,
- unsigned char *pubkey,
- int pubkeylen,
- const unsigned char *tweak
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_tweak_mul(
+ const secp256k1_context* ctx,
+ secp256k1_pubkey *pubkey,
+ const unsigned char *tweak
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Updates the context randomization.
* Returns: 1: randomization successfully updated
* 0: error
- * In: ctx: pointer to a context object (cannot be NULL)
- * seed32: pointer to a 32-byte random seed (NULL resets to initial state)
+ * Args: ctx: pointer to a context object (cannot be NULL)
+ * In: seed32: pointer to a 32-byte random seed (NULL resets to initial state)
*/
-SECP256K1_WARN_UNUSED_RESULT int secp256k1_context_randomize(
- secp256k1_context_t* ctx,
- const unsigned char *seed32
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_context_randomize(
+ secp256k1_context* ctx,
+ const unsigned char *seed32
) SECP256K1_ARG_NONNULL(1);
+/** Add a number of public keys together.
+ * Returns: 1: the sum of the public keys is valid.
+ * 0: the sum of the public keys is not valid.
+ * Args: ctx: pointer to a context object
+ * Out: out: pointer to a public key object for placing the resulting public key
+ * (cannot be NULL)
+ * In: ins: pointer to array of pointers to public keys (cannot be NULL)
+ * n: the number of public keys to add together (must be at least 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(2) SECP256K1_ARG_NONNULL(3);
# ifdef __cplusplus
}
diff --git a/src/secp256k1/include/secp256k1_ecdh.h b/src/secp256k1/include/secp256k1_ecdh.h
new file mode 100644
index 0000000000..4b84d7a963
--- /dev/null
+++ b/src/secp256k1/include/secp256k1_ecdh.h
@@ -0,0 +1,31 @@
+#ifndef _SECP256K1_ECDH_
+# define _SECP256K1_ECDH_
+
+# include "secp256k1.h"
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+/** Compute an EC Diffie-Hellman secret in constant time
+ * Returns: 1: exponentiation was successful
+ * 0: scalar was invalid (zero or overflow)
+ * Args: ctx: pointer to a context object (cannot be NULL)
+ * Out: result: a 32-byte array which will be populated by an ECDH
+ * secret computed from the point and scalar
+ * In: pubkey: a pointer to a secp256k1_pubkey containing an
+ * initialized public key
+ * privkey: a 32-byte scalar with which to multiply the point
+ */
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdh(
+ const secp256k1_context* ctx,
+ unsigned char *result,
+ const secp256k1_pubkey *pubkey,
+ const unsigned char *privkey
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
diff --git a/src/secp256k1/include/secp256k1_recovery.h b/src/secp256k1/include/secp256k1_recovery.h
new file mode 100644
index 0000000000..0553797253
--- /dev/null
+++ b/src/secp256k1/include/secp256k1_recovery.h
@@ -0,0 +1,110 @@
+#ifndef _SECP256K1_RECOVERY_
+# define _SECP256K1_RECOVERY_
+
+# include "secp256k1.h"
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+/** Opaque data structured that holds a parsed ECDSA signature,
+ * supporting pubkey recovery.
+ *
+ * The exact representation of data inside is implementation defined and not
+ * guaranteed to be portable between different platforms or versions. It is
+ * however guaranteed to be 65 bytes in size, and can be safely copied/moved.
+ * If you need to convert to a format suitable for storage or transmission, use
+ * the secp256k1_ecdsa_signature_serialize_* and
+ * secp256k1_ecdsa_signature_parse_* functions.
+ *
+ * Furthermore, it is guaranteed that identical signatures (including their
+ * recoverability) will have identical representation, so they can be
+ * memcmp'ed.
+ */
+typedef struct {
+ 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
+ * recid: the recovery id (0, 1, 2 or 3)
+ */
+SECP256K1_API int secp256k1_ecdsa_recoverable_signature_parse_compact(
+ const secp256k1_context* ctx,
+ secp256k1_ecdsa_recoverable_signature* sig,
+ const unsigned char *input64,
+ int recid
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
+
+/** Convert a recoverable signature into a normal signature.
+ *
+ * Returns: 1
+ * Out: sig: a pointer to a normal signature (cannot be NULL).
+ * In: sigin: a pointer to a recoverable signature (cannot be NULL).
+ */
+SECP256K1_API int secp256k1_ecdsa_recoverable_signature_convert(
+ const secp256k1_context* ctx,
+ secp256k1_ecdsa_signature* sig,
+ const secp256k1_ecdsa_recoverable_signature* sigin
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
+
+/** Serialize an ECDSA signature in compact format (64 bytes + recovery id).
+ *
+ * Returns: 1
+ * Args: ctx: a secp256k1 context object
+ * Out: output64: a pointer to a 64-byte array of the compact signature (cannot be NULL)
+ * recid: a pointer to an integer to hold the recovery id (can be NULL).
+ * In: sig: a pointer to an initialized signature object (cannot be NULL)
+ */
+SECP256K1_API int secp256k1_ecdsa_recoverable_signature_serialize_compact(
+ const secp256k1_context* ctx,
+ unsigned char *output64,
+ int *recid,
+ const secp256k1_ecdsa_recoverable_signature* sig
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
+
+/** Create a recoverable ECDSA signature.
+ *
+ * Returns: 1: signature created
+ * 0: the nonce generation function failed, or the private key was invalid.
+ * Args: ctx: pointer to a context object, initialized for signing (cannot be NULL)
+ * Out: sig: pointer to an array where the signature will be placed (cannot be NULL)
+ * In: msg32: the 32-byte message hash being signed (cannot be NULL)
+ * seckey: pointer to a 32-byte secret key (cannot be NULL)
+ * noncefp:pointer to a nonce generation function. If NULL, secp256k1_nonce_function_default is used
+ * ndata: pointer to arbitrary data used by the nonce generation function (can be NULL)
+ */
+SECP256K1_API int secp256k1_ecdsa_sign_recoverable(
+ const secp256k1_context* ctx,
+ secp256k1_ecdsa_recoverable_signature *sig,
+ const unsigned char *msg32,
+ const unsigned char *seckey,
+ secp256k1_nonce_function noncefp,
+ const void *ndata
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
+
+/** Recover an ECDSA public key from a signature.
+ *
+ * Returns: 1: public key successfully recovered (which guarantees a correct signature).
+ * 0: otherwise.
+ * Args: ctx: pointer to a context object, initialized for verification (cannot be NULL)
+ * Out: pubkey: pointer to the recovered public key (cannot be NULL)
+ * In: sig: pointer to initialized signature that supports pubkey recovery (cannot be NULL)
+ * msg32: the 32-byte message hash assumed to be signed (cannot be NULL)
+ */
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_recover(
+ const secp256k1_context* ctx,
+ secp256k1_pubkey *pubkey,
+ const secp256k1_ecdsa_recoverable_signature *sig,
+ const unsigned char *msg32
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
diff --git a/src/secp256k1/include/secp256k1_schnorr.h b/src/secp256k1/include/secp256k1_schnorr.h
new file mode 100644
index 0000000000..dc32fec1ea
--- /dev/null
+++ b/src/secp256k1/include/secp256k1_schnorr.h
@@ -0,0 +1,173 @@
+#ifndef _SECP256K1_SCHNORR_
+# define _SECP256K1_SCHNORR_
+
+# include "secp256k1.h"
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+/** Create a signature using a custom EC-Schnorr-SHA256 construction. It
+ * produces non-malleable 64-byte signatures which support public key recovery
+ * batch validation, and multiparty signing.
+ * Returns: 1: signature created
+ * 0: the nonce generation function failed, or the private key was
+ * invalid.
+ * Args: ctx: pointer to a context object, initialized for signing
+ * (cannot be NULL)
+ * Out: sig64: pointer to a 64-byte array where the signature will be
+ * placed (cannot be NULL)
+ * In: msg32: the 32-byte message hash being signed (cannot be NULL)
+ * seckey: pointer to a 32-byte secret key (cannot be NULL)
+ * noncefp:pointer to a nonce generation function. If NULL,
+ * secp256k1_nonce_function_default is used
+ * ndata: pointer to arbitrary data used by the nonce generation
+ * function (can be NULL)
+ */
+SECP256K1_API int secp256k1_schnorr_sign(
+ const secp256k1_context* ctx,
+ unsigned char *sig64,
+ const unsigned char *msg32,
+ 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);
+
+/** Verify a signature created by secp256k1_schnorr_sign.
+ * Returns: 1: correct signature
+ * 0: incorrect signature
+ * Args: ctx: a secp256k1 context object, initialized for verification.
+ * In: sig64: the 64-byte signature being verified (cannot be NULL)
+ * msg32: the 32-byte message hash being verified (cannot be NULL)
+ * pubkey: the public key to verify with (cannot be NULL)
+ */
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_schnorr_verify(
+ const secp256k1_context* ctx,
+ const unsigned char *sig64,
+ const unsigned char *msg32,
+ const secp256k1_pubkey *pubkey
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
+
+/** Recover an EC public key from a Schnorr signature created using
+ * secp256k1_schnorr_sign.
+ * Returns: 1: public key successfully recovered (which guarantees a correct
+ * signature).
+ * 0: otherwise.
+ * Args: ctx: pointer to a context object, initialized for
+ * verification (cannot be NULL)
+ * Out: pubkey: pointer to a pubkey to set to the recovered public key
+ * (cannot be NULL).
+ * In: sig64: signature as 64 byte array (cannot be NULL)
+ * msg32: the 32-byte message hash assumed to be signed (cannot
+ * be NULL)
+ */
+SECP256K1_API int secp256k1_schnorr_recover(
+ const secp256k1_context* ctx,
+ secp256k1_pubkey *pubkey,
+ const unsigned char *sig64,
+ const unsigned char *msg32
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
+
+/** Generate a nonce pair deterministically for use with
+ * secp256k1_schnorr_partial_sign.
+ * Returns: 1: valid nonce pair was generated.
+ * 0: otherwise (nonce generation function failed)
+ * Args: ctx: pointer to a context object, initialized for signing
+ * (cannot be NULL)
+ * Out: pubnonce: public side of the nonce (cannot be NULL)
+ * privnonce32: private side of the nonce (32 byte) (cannot be NULL)
+ * In: msg32: the 32-byte message hash assumed to be signed (cannot
+ * be NULL)
+ * sec32: the 32-byte private key (cannot be NULL)
+ * noncefp: pointer to a nonce generation function. If NULL,
+ * secp256k1_nonce_function_default is used
+ * noncedata: pointer to arbitrary data used by the nonce generation
+ * function (can be NULL)
+ *
+ * Do not use the output as a private/public key pair for signing/validation.
+ */
+SECP256K1_API int secp256k1_schnorr_generate_nonce_pair(
+ const secp256k1_context* ctx,
+ secp256k1_pubkey *pubnonce,
+ unsigned char *privnonce32,
+ const unsigned char *msg32,
+ const unsigned char *sec32,
+ secp256k1_nonce_function noncefp,
+ const void* noncedata
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
+
+/** Produce a partial Schnorr signature, which can be combined using
+ * secp256k1_schnorr_partial_combine, to end up with a full signature that is
+ * verifiable using secp256k1_schnorr_verify.
+ * Returns: 1: signature created successfully.
+ * 0: no valid signature exists with this combination of keys, nonces
+ * and message (chance around 1 in 2^128)
+ * -1: invalid private key, nonce, or public nonces.
+ * Args: ctx: pointer to context object, initialized for signing (cannot
+ * be NULL)
+ * Out: sig64: pointer to 64-byte array to put partial signature in
+ * In: msg32: pointer to 32-byte message to sign
+ * sec32: pointer to 32-byte private key
+ * pubnonce_others: pointer to pubkey containing the sum of the other's
+ * nonces (see secp256k1_ec_pubkey_combine)
+ * secnonce32: pointer to 32-byte array containing our nonce
+ *
+ * The intended procedure for creating a multiparty signature is:
+ * - Each signer S[i] with private key x[i] and public key Q[i] runs
+ * secp256k1_schnorr_generate_nonce_pair to produce a pair (k[i],R[i]) of
+ * private/public nonces.
+ * - All signers communicate their public nonces to each other (revealing your
+ * private nonce can lead to discovery of your private key, so it should be
+ * considered secret).
+ * - All signers combine all the public nonces they received (excluding their
+ * own) using secp256k1_ec_pubkey_combine to obtain an
+ * Rall[i] = sum(R[0..i-1,i+1..n]).
+ * - All signers produce a partial signature using
+ * secp256k1_schnorr_partial_sign, passing in their own private key x[i],
+ * their own private nonce k[i], and the sum of the others' public nonces
+ * Rall[i].
+ * - All signers communicate their partial signatures to each other.
+ * - Someone combines all partial signatures using
+ * secp256k1_schnorr_partial_combine, to obtain a full signature.
+ * - The resulting signature is validatable using secp256k1_schnorr_verify, with
+ * public key equal to the result of secp256k1_ec_pubkey_combine of the
+ * signers' public keys (sum(Q[0..n])).
+ *
+ * Note that secp256k1_schnorr_partial_combine and secp256k1_ec_pubkey_combine
+ * function take their arguments in any order, and it is possible to
+ * pre-combine several inputs already with one call, and add more inputs later
+ * by calling the function again (they are commutative and associative).
+ */
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_schnorr_partial_sign(
+ const secp256k1_context* ctx,
+ unsigned char *sig64,
+ const unsigned char *msg32,
+ const unsigned char *sec32,
+ const secp256k1_pubkey *pubnonce_others,
+ const unsigned char *secnonce32
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5) SECP256K1_ARG_NONNULL(6);
+
+/** Combine multiple Schnorr partial signatures.
+ * Returns: 1: the passed signatures were successfully combined.
+ * 0: the resulting signature is not valid (chance of 1 in 2^256)
+ * -1: some inputs were invalid, or the signatures were not created
+ * using the same set of nonces
+ * Args: ctx: pointer to a context object
+ * Out: sig64: pointer to a 64-byte array to place the combined signature
+ * (cannot be NULL)
+ * In: sig64sin: pointer to an array of n pointers to 64-byte input
+ * signatures
+ * n: the number of signatures to combine (at least 1)
+ */
+SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_schnorr_partial_combine(
+ const secp256k1_context* ctx,
+ unsigned char *sig64,
+ const unsigned char * const * sig64sin,
+ size_t n
+) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif