crypto/secp256k1: update to github.com/bitcoin-core/secp256k1 @ 9d560f9 (#3544)

- Use defined constants instead of hard-coding their integer value.
- Allocate secp256k1 structs on the C stack instead of converting []byte
- Remove dead code

4 files changed, 145 insertions, 287 deletions

diff --git a/crypto/secp256k1/libsecp256k1/include/secp256k1.h b/crypto/secp256k1/libsecp256k1/include/secp256k1.h
index 23378de1f..f268e309d 100644
--- a/crypto/secp256k1/libsecp256k1/include/secp256k1.h
+++ b/crypto/secp256k1/libsecp256k1/include/secp256k1.h
@@ -47,11 +47,8 @@ typedef struct secp256k1_context_struct secp256k1_context;
  *  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.
+ *  If you need to convert to a format suitable for storage, transmission, or
+ *  comparison, use secp256k1_ec_pubkey_serialize and secp256k1_ec_pubkey_parse.
  */
 typedef struct {
     unsigned char data[64];
@@ -62,12 +59,9 @@ typedef struct {
  *  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
+ *  If you need to convert to a format suitable for storage, transmission, or
+ *  comparison, 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];
@@ -147,12 +141,23 @@ typedef int (*secp256k1_nonce_function)(
 #  define SECP256K1_ARG_NONNULL(_x)
 # 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_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  (1 << 0)
+#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.
  *
@@ -218,7 +223,7 @@ SECP256K1_API void secp256k1_context_set_illegal_callback(
  *  crashing.
  *
  *  Args: ctx:  an existing context object (cannot be NULL)
- *  In:   fun:  a pointer to a function to call when an interal error occurs,
+ *  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.
@@ -253,15 +258,17 @@ 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
- *                    compressed==1) byte array to place the serialized key in.
- *        outputlen:  a pointer to an integer which will contain the serialized
- *                    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.
+ *  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,
@@ -271,6 +278,27 @@ SECP256K1_API int secp256k1_ec_pubkey_serialize(
     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.
@@ -279,7 +307,12 @@ SECP256K1_API int secp256k1_ec_pubkey_serialize(
  *  In:   input:    a pointer to the signature to be parsed
  *        inputlen: the length of the array pointed to be input
  *
- *  Note that this function also supports some violations of DER and even BER.
+ *  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,
@@ -306,6 +339,21 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_der(
     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
@@ -314,6 +362,15 @@ SECP256K1_API int secp256k1_ecdsa_signature_serialize_der(
  *  In:      sig:       the signature being verified (cannot be NULL)
  *           msg32:     the 32-byte message hash being verified (cannot be NULL)
  *           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_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
     const secp256k1_context* ctx,
@@ -322,14 +379,62 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
     const secp256k1_pubkey *pubkey
 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
 
+/** 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.
+ */
+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 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 secp256k1_nonce_function_default;
+SECP256K1_API extern const secp256k1_nonce_function secp256k1_nonce_function_default;
 
 /** Create an ECDSA signature.
  *
@@ -342,32 +447,8 @@ extern const secp256k1_nonce_function secp256k1_nonce_function_default;
  *           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)
  *
- * 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.
+ * The created signature is always in lower-S form. See
+ * secp256k1_ecdsa_signature_normalize for more details.
  */
 SECP256K1_API int secp256k1_ecdsa_sign(
     const secp256k1_context* ctx,
@@ -404,55 +485,6 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_create(
     const unsigned char *seckey
 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
 
-/** Export a private key in BER format.
- *
- *  Returns: 1 if the private key was valid.
- *  Args: ctx:        pointer to a context object, initialized for signing (cannot
- *                    be NULL)
- *  Out: privkey:     pointer to an array for storing the private key in BER.
- *                    Should have space for 279 bytes, and cannot be NULL.
- *       privkeylen:  Pointer to an int where the length of the private key in
- *                    privkey will be stored.
- *  In:  seckey:      pointer to a 32-byte secret key to export.
- *       flags:       SECP256K1_EC_COMPRESSED if the key should be exported in
- *                    compressed format.
- *
- *  This function is purely meant for compatibility with applications that
- *  require BER encoded keys. When working with secp256k1-specific code, the
- *  simple 32-byte private keys are sufficient.
- *
- *  Note that this function does not guarantee correct DER output. It is
- *  guaranteed to be parsable by secp256k1_ec_privkey_import.
- */
-SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_export(
-    const secp256k1_context* ctx,
-    unsigned char *privkey,
-    size_t *privkeylen,
-    const unsigned char *seckey,
-    unsigned int flags
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
-
-/** Import a private key in DER format.
- * Returns: 1 if a private key was extracted.
- * Args: ctx:        pointer to a context object (cannot be NULL).
- * Out:  seckey:     pointer to a 32-byte array for storing the private key.
- *                   (cannot be NULL).
- * In:   privkey:    pointer to a private key in DER format (cannot be NULL).
- *       privkeylen: length of the DER private key pointed to be privkey.
- *
- * This function will accept more than just strict DER, and even allow some BER
- * violations. The public key stored inside the DER-encoded private key is not
- * verified for correctness, nor are the curve parameters. Use this function
- * only if you know in advance it is supposed to contain a secp256k1 private
- * key.
- */
-SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_privkey_import(
-    const secp256k1_context* ctx,
-    unsigned char *seckey,
-    const unsigned char *privkey,
-    size_t privkeylen
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
-
 /** 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
@@ -526,18 +558,16 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_context_randomize(
  *  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 pubkey for placing the resulting public key
+ *  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)
- *  Use secp256k1_ec_pubkey_compress and secp256k1_ec_pubkey_decompress if the
- *  uncompressed format is needed.
  */
 SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_combine(
     const secp256k1_context* ctx,
     secp256k1_pubkey *out,
     const secp256k1_pubkey * const * ins,
-    int n
+    size_t n
 ) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
 
 # ifdef __cplusplus
diff --git a/crypto/secp256k1/libsecp256k1/include/secp256k1_ecdh.h b/crypto/secp256k1/libsecp256k1/include/secp256k1_ecdh.h
index db520f446..4b84d7a96 100644
--- a/crypto/secp256k1/libsecp256k1/include/secp256k1_ecdh.h
+++ b/crypto/secp256k1/libsecp256k1/include/secp256k1_ecdh.h
@@ -10,17 +10,18 @@ extern "C" {
 /** 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:      point:    pointer to a public point
- *           scalar:   a 32-byte scalar with which to multiply the point
+ *  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 *point,
-  const unsigned char *scalar
+  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
diff --git a/crypto/secp256k1/libsecp256k1/include/secp256k1_recovery.h b/crypto/secp256k1/libsecp256k1/include/secp256k1_recovery.h
index c9b8c0a30..055379725 100644
--- a/crypto/secp256k1/libsecp256k1/include/secp256k1_recovery.h
+++ b/crypto/secp256k1/libsecp256k1/include/secp256k1_recovery.h
@@ -65,7 +65,7 @@ SECP256K1_API int secp256k1_ecdsa_recoverable_signature_serialize_compact(
     unsigned char *output64,
     int *recid,
     const secp256k1_ecdsa_recoverable_signature* sig
-) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
 
 /** Create a recoverable ECDSA signature.
  *
@@ -92,7 +92,7 @@ SECP256K1_API int secp256k1_ecdsa_sign_recoverable(
  *  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 recoved public key (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)
  */
diff --git a/crypto/secp256k1/libsecp256k1/include/secp256k1_schnorr.h b/crypto/secp256k1/libsecp256k1/include/secp256k1_schnorr.h
deleted file mode 100644
index 9b4f5b607..000000000
--- a/crypto/secp256k1/libsecp256k1/include/secp256k1_schnorr.h
+++ /dev/null
@@ -1,173 +0,0 @@
-#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,
-  int n
-) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
-
-# ifdef __cplusplus
-}
-# endif
-
-#endif