diff --git a/.gitignore b/.gitignore
index 46114e4be6..e930572946 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,7 @@ bench_inv
 bench_ecdh
 bench_sign
 bench_verify
+bench_verify_schnorr
 bench_recover
 bench_internal
 tests
diff --git a/.travis.yml b/.travis.yml
index 282c8b8d5e..57a3f53db1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ compiler:
   - gcc
 env:
   global:
-    - FIELD=auto  BIGNUM=auto  SCALAR=auto  ENDOMORPHISM=no  STATICPRECOMPUTATION=no ASM=no  BUILD=check  EXTRAFLAGS= HOST= ECDH=no
+    - FIELD=auto  BIGNUM=auto  SCALAR=auto  ENDOMORPHISM=no  STATICPRECOMPUTATION=no ASM=no  BUILD=check  EXTRAFLAGS= HOST= ECDH=no schnorr=NO
   matrix:
     - SCALAR=32bit
     - SCALAR=32bit    FIELD=32bit       ECDH=yes
@@ -18,10 +18,10 @@ env:
     - FIELD=64bit     ENDOMORPHISM=yes  ECDH=yes
     - FIELD=64bit                       ASM=x86_64
     - FIELD=64bit     ENDOMORPHISM=yes  ASM=x86_64
-    - FIELD=32bit
+    - FIELD=32bit     SCHNORR=yes
     - FIELD=32bit     ENDOMORPHISM=yes
     - BIGNUM=no
-    - BIGNUM=no       ENDOMORPHISM=yes
+    - BIGNUM=no       ENDOMORPHISM=yes SCHNORR=yes
     - BIGNUM=no       STATICPRECOMPUTATION=no
     - BUILD=distcheck
     - EXTRAFLAGS=CFLAGS=-DDETERMINISTIC
@@ -58,5 +58,5 @@ before_script: ./autogen.sh
 script:
  - if [ -n "$HOST" ]; then export USE_HOST="--host=$HOST"; fi
  - if [ "x$HOST" = "xi686-linux-gnu" ]; then export CC="$CC -m32"; fi
- - ./configure --enable-endomorphism=$ENDOMORPHISM --with-field=$FIELD --with-bignum=$BIGNUM --with-scalar=$SCALAR --enable-ecmult-static-precomputation=$STATICPRECOMPUTATION --enable-module-ecdh=$ECDH $EXTRAFLAGS $USE_HOST && make -j2 $BUILD
+ - ./configure --enable-endomorphism=$ENDOMORPHISM --with-field=$FIELD --with-bignum=$BIGNUM --with-scalar=$SCALAR --enable-ecmult-static-precomputation=$STATICPRECOMPUTATION --enable-module-ecdh=$ECDH --enable-module-schnorr=$SCHNORR $EXTRAFLAGS $USE_HOST && make -j2 $BUILD
 os: linux
diff --git a/Makefile.am b/Makefile.am
index 8f0ffdb456..881607d35d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -101,3 +101,7 @@ EXTRA_DIST = autogen.sh src/gen_context.c src/basic-config.h
 if ENABLE_MODULE_ECDH
 include src/modules/ecdh/Makefile.am.include
 endif
+
+if ENABLE_MODULE_SCHNORR
+include src/modules/schnorr/Makefile.am.include
+endif
diff --git a/configure.ac b/configure.ac
index e3126dbe26..8491982947 100644
--- a/configure.ac
+++ b/configure.ac
@@ -107,6 +107,11 @@ AC_ARG_ENABLE(module_ecdh,
     [enable_module_ecdh=$enableval],
     [enable_module_ecdh=no])
 
+AC_ARG_ENABLE(module_schnorr,
+    AS_HELP_STRING([--enable-module-schnorr],[enable Schnorr signature module (default is no)]),
+    [enable_module_schnorr=$enableval],
+    [enable_module_schnorr=no])
+
 AC_ARG_WITH([field], [AS_HELP_STRING([--with-field=64bit|32bit|auto],
 [Specify Field Implementation. Default is auto])],[req_field=$withval], [req_field=auto])
 
@@ -324,6 +329,10 @@ if test x"$enable_module_ecdh" = x"yes"; then
   AC_DEFINE(ENABLE_MODULE_ECDH, 1, [Define this symbol to enable the ECDH module])
 fi
 
+if test x"$enable_module_schnorr" = x"yes"; then
+  AC_DEFINE(ENABLE_MODULE_SCHNORR, 1, [Define this symbol to enable the Schnorr signature module])
+fi
+
 AC_C_BIGENDIAN()
 
 AC_MSG_NOTICE([Using assembly optimizations: $set_asm])
@@ -333,6 +342,8 @@ AC_MSG_NOTICE([Using scalar implementation: $set_scalar])
 AC_MSG_NOTICE([Using endomorphism optimizations: $use_endomorphism])
 AC_MSG_NOTICE([Building ECDH module: $enable_module_ecdh])
 
+AC_MSG_NOTICE([Building Schnorr signatures module: $enable_module_schnorr])
+
 AC_CONFIG_HEADERS([src/libsecp256k1-config.h])
 AC_CONFIG_FILES([Makefile libsecp256k1.pc])
 AC_SUBST(SECP_INCLUDES)
@@ -343,6 +354,7 @@ AM_CONDITIONAL([USE_TESTS], [test x"$use_tests" != x"no"])
 AM_CONDITIONAL([USE_BENCHMARK], [test x"$use_benchmark" = x"yes"])
 AM_CONDITIONAL([USE_ECMULT_STATIC_PRECOMPUTATION], [test x"$use_ecmult_static_precomputation" = x"yes"])
 AM_CONDITIONAL([ENABLE_MODULE_ECDH], [test x"$enable_module_ecdh" = x"yes"])
+AM_CONDITIONAL([ENABLE_MODULE_SCHNORR], [test x"$enable_module_schnorr" = x"yes"])
 
 dnl make sure nothing new is exported so that we don't break the cache
 PKGCONFIG_PATH_TEMP="$PKG_CONFIG_PATH"
diff --git a/include/secp256k1.h b/include/secp256k1.h
index 411156ac1d..1b8361e00e 100644
--- a/include/secp256k1.h
+++ b/include/secp256k1.h
@@ -252,6 +252,8 @@ SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_verify(
  * 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)
+ *          algo16:    pointer to a 16-byte array describing the signature
+ *                     algorithm (will be NULL for ECDSA for compatibility).
  *          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.
@@ -264,6 +266,7 @@ typedef int (*secp256k1_nonce_function_t)(
   unsigned char *nonce32,
   const unsigned char *msg32,
   const unsigned char *key32,
+  const unsigned char *algo16,
   unsigned int attempt,
   const void *data
 );
@@ -425,6 +428,23 @@ SECP256K1_WARN_UNUSED_RESULT int secp256k1_context_randomize(
   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.
+ *  In:     ctx:        pointer to a context object
+ *          out:        pointer to pubkey for placing the resulting public key
+ *                      (cannot be NULL)
+ *          n:          the number of public keys to add together (must be at least 1)
+ *          ins:        pointer to array of pointers to public keys (cannot be NULL)
+ *  Use secp256k1_ec_pubkey_compress and secp256k1_ec_pubkey_decompress if the
+ *  uncompressed format is needed.
+ */
+SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_combine(
+  const secp256k1_context_t* ctx,
+  secp256k1_pubkey_t *out,
+  int n,
+  const secp256k1_pubkey_t * const * ins
+) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
 
 # ifdef __cplusplus
 }
diff --git a/include/secp256k1_schnorr.h b/include/secp256k1_schnorr.h
new file mode 100644
index 0000000000..ff7b977f40
--- /dev/null
+++ b/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.
+ *  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)
+ *  Out:     sig64:  pointer to a 64-byte array where the signature will be
+ *                   placed (cannot be NULL)
+ */
+int secp256k1_schnorr_sign(
+  const secp256k1_context_t* ctx,
+  const unsigned char *msg32,
+  unsigned char *sig64,
+  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);
+
+/** Verify a signature created by secp256k1_schnorr_sign.
+ *  Returns: 1: correct signature
+ *           0: incorrect signature
+ *  In:      ctx:       a secp256k1 context object, initialized for verification.
+ *           msg32:     the 32-byte message hash being verified (cannot be NULL)
+ *           sig64:     the 64-byte signature being verified (cannot be NULL)
+ *           pubkey:    the public key to verify with (cannot be NULL)
+ */
+SECP256K1_WARN_UNUSED_RESULT int secp256k1_schnorr_verify(
+  const secp256k1_context_t* ctx,
+  const unsigned char *msg32,
+  const unsigned char *sig64,
+  const secp256k1_pubkey_t *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.
+ *  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)
+ *  Out:     pubkey:     pointer to a pubkey to set to the recovered public key
+ *                       (cannot be NULL).
+ */
+int secp256k1_schnorr_recover(
+  const secp256k1_context_t* ctx,
+  const unsigned char *msg32,
+  const unsigned char *sig64,
+  secp256k1_pubkey_t *pubkey
+) 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)
+ *  In:      ctx:         pointer to a context object, initialized for signing
+ *                        (cannot be NULL)
+ *           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)
+ *  Out:     pubnonce:    public side of the nonce (cannot be NULL)
+ *           privnonce32: private side of the nonce (32 byte) (cannot be NULL)
+ *
+ *  Do not use the output as a private/public key pair for signing/validation.
+ */
+int secp256k1_schnorr_generate_nonce_pair(
+  const secp256k1_context_t* ctx,
+  const unsigned char *msg32,
+  const unsigned char *sec32,
+  secp256k1_nonce_function_t noncefp,
+  const void* noncedata,
+  secp256k1_pubkey_t *pubnonce,
+  unsigned char *privnonce32
+) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(6) SECP256K1_ARG_NONNULL(7);
+
+/** 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 succesfully.
+ *           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.
+ *  In:   ctx:             pointer to context object, initialized for signing (cannot
+ *                         be NULL)
+ *        msg32:           pointer to 32-byte message to sign
+ *        sec32:           pointer to 32-byte private key
+ *        secnonce32:      pointer to 32-byte array containing our nonce
+ *        pubnonce_others: pointer to pubkey containing the sum of the other's
+ *                         nonces (see secp256k1_ec_pubkey_combine)
+ *  Out:  sig64:           pointer to 64-byte array to put partial signature in
+ *
+ * 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_WARN_UNUSED_RESULT int secp256k1_schnorr_partial_sign(
+  const secp256k1_context_t* ctx,
+  const unsigned char *msg32,
+  unsigned char *sig64,
+  const unsigned char *sec32,
+  const unsigned char *secnonce32,
+  const secp256k1_pubkey_t *pubnonce_others
+) 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 succesfully 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
+ * In:     ctx:      pointer to a context object
+ *         sig64:    pointer to a 64-byte array to place the combined signature
+ *                   (cannot be NULL)
+ *         n:        the number of signatures to combine (at least 1)
+ * Out:    sig64sin: pointer to an array of n pointers to 64-byte input
+ *                   signatures
+ */
+SECP256K1_WARN_UNUSED_RESULT int secp256k1_schnorr_partial_combine(
+  const secp256k1_context_t* ctx,
+  unsigned char *sig64,
+  int n,
+  const unsigned char * const * sig64sin
+) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif
diff --git a/src/bench_schnorr_verify.c b/src/bench_schnorr_verify.c
new file mode 100644
index 0000000000..274b6e02db
--- /dev/null
+++ b/src/bench_schnorr_verify.c
@@ -0,0 +1,69 @@
+/**********************************************************************
+ * Copyright (c) 2014 Pieter Wuille                                   *
+ * Distributed under the MIT software license, see the accompanying   *
+ * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
+ **********************************************************************/
+
+#include <stdio.h>
+#include <string.h>
+
+#include "include/secp256k1.h"
+#include "include/secp256k1_schnorr.h"
+#include "util.h"
+#include "bench.h"
+
+typedef struct {
+    unsigned char key[32];
+    unsigned char sig[64];
+    unsigned char pubkey[33];
+    int pubkeylen;
+} benchmark_schnorr_sig_t;
+
+typedef struct {
+    secp256k1_context_t *ctx;
+    unsigned char msg[32];
+    benchmark_schnorr_sig_t sigs[64];
+    int numsigs;
+} benchmark_schnorr_verify_t;
+
+static void benchmark_schnorr_init(void* arg) {
+    int i, k;
+    benchmark_schnorr_verify_t* data = (benchmark_schnorr_verify_t*)arg;
+
+    for (i = 0; i < 32; i++) data->msg[i] = 1 + i;
+    for (k = 0; k < data->numsigs; k++) {
+        secp256k1_pubkey_t pubkey;
+        for (i = 0; i < 32; i++) data->sigs[k].key[i] = 33 + i + k;
+        secp256k1_schnorr_sign(data->ctx, data->msg, data->sigs[k].sig, data->sigs[k].key, NULL, NULL);
+        data->sigs[k].pubkeylen = 33;
+        CHECK(secp256k1_ec_pubkey_create(data->ctx, &pubkey, data->sigs[k].key));
+        CHECK(secp256k1_ec_pubkey_serialize(data->ctx, data->sigs[k].pubkey, &data->sigs[k].pubkeylen, &pubkey, 1));
+    }
+}
+
+static void benchmark_schnorr_verify(void* arg) {
+    int i;
+    benchmark_schnorr_verify_t* data = (benchmark_schnorr_verify_t*)arg;
+
+    for (i = 0; i < 20000 / data->numsigs; i++) {
+        secp256k1_pubkey_t pubkey;
+        data->sigs[0].sig[(i >> 8) % 64] ^= (i & 0xFF);
+        CHECK(secp256k1_ec_pubkey_parse(data->ctx, &pubkey, data->sigs[0].pubkey, data->sigs[0].pubkeylen));
+        CHECK(secp256k1_schnorr_verify(data->ctx, data->msg, data->sigs[0].sig, &pubkey) == ((i & 0xFF) == 0));
+        data->sigs[0].sig[(i >> 8) % 64] ^= (i & 0xFF);
+    }
+}
+
+
+
+int main(void) {
+    benchmark_schnorr_verify_t data;
+
+    data.ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
+
+    data.numsigs = 1;
+    run_benchmark("schnorr_verify", benchmark_schnorr_verify, benchmark_schnorr_init, NULL, &data, 10, 20000);
+
+    secp256k1_context_destroy(data.ctx);
+    return 0;
+}
diff --git a/src/modules/schnorr/Makefile.am.include b/src/modules/schnorr/Makefile.am.include
new file mode 100644
index 0000000000..bad4cb7c5b
--- /dev/null
+++ b/src/modules/schnorr/Makefile.am.include
@@ -0,0 +1,11 @@
+include_HEADERS += include/secp256k1_schnorr.h
+noinst_HEADERS += src/modules/schnorr/main_impl.h
+noinst_HEADERS += src/modules/schnorr/schnorr.h
+noinst_HEADERS += src/modules/schnorr/schnorr_impl.h
+noinst_HEADERS += src/modules/schnorr/tests_impl.h
+if USE_BENCHMARK
+noinst_PROGRAMS += bench_schnorr_verify
+bench_schnorr_verify_SOURCES = src/bench_schnorr_verify.c
+bench_schnorr_verify_LDADD = libsecp256k1.la $(SECP_LIBS)
+bench_schnorr_verify_LDFLAGS = -static
+endif
diff --git a/src/modules/schnorr/main_impl.h b/src/modules/schnorr/main_impl.h
new file mode 100644
index 0000000000..f5250bffd0
--- /dev/null
+++ b/src/modules/schnorr/main_impl.h
@@ -0,0 +1,163 @@
+/**********************************************************************
+ * Copyright (c) 2014-2015 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying   *
+ * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
+ **********************************************************************/
+
+#ifndef SECP256K1_MODULE_SCHNORR_MAIN
+#define SECP256K1_MODULE_SCHNORR_MAIN
+
+#include "modules/schnorr/schnorr_impl.h"
+
+static void secp256k1_schnorr_msghash_sha256(unsigned char *h32, const unsigned char *r32, const unsigned char *msg32) {
+    secp256k1_sha256_t sha;
+    secp256k1_sha256_initialize(&sha);
+    secp256k1_sha256_write(&sha, r32, 32);
+    secp256k1_sha256_write(&sha, msg32, 32);
+    secp256k1_sha256_finalize(&sha, h32);
+}
+
+static const unsigned char secp256k1_schnorr_algo16[16] = "Schnorr+SHA256  ";
+
+int secp256k1_schnorr_sign(const secp256k1_context_t* ctx, const unsigned char *msg32, unsigned char *sig64, const unsigned char *seckey, secp256k1_nonce_function_t noncefp, const void* noncedata) {
+    secp256k1_scalar_t sec, non;
+    int ret = 0;
+    int overflow = 0;
+    unsigned int count = 0;
+    ARG_CHECK(ctx != NULL);
+    ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));
+    ARG_CHECK(msg32 != NULL);
+    ARG_CHECK(sig64 != NULL);
+    ARG_CHECK(seckey != NULL);
+    if (noncefp == NULL) {
+        noncefp = secp256k1_nonce_function_default;
+    }
+
+    secp256k1_scalar_set_b32(&sec, seckey, NULL);
+    while (1) {
+        unsigned char nonce32[32];
+        ret = noncefp(nonce32, msg32, seckey, secp256k1_schnorr_algo16, count, noncedata);
+        if (!ret) {
+            break;
+        }
+        secp256k1_scalar_set_b32(&non, nonce32, &overflow);
+        memset(nonce32, 0, 32);
+        if (!secp256k1_scalar_is_zero(&non) && !overflow) {
+            if (secp256k1_schnorr_sig_sign(&ctx->ecmult_gen_ctx, sig64, &sec, &non, NULL, secp256k1_schnorr_msghash_sha256, msg32)) {
+                break;
+            }
+        }
+        count++;
+    }
+    if (!ret) {
+        memset(sig64, 0, 64);
+    }
+    secp256k1_scalar_clear(&non);
+    secp256k1_scalar_clear(&sec);
+    return ret;
+}
+
+int secp256k1_schnorr_verify(const secp256k1_context_t* ctx, const unsigned char *msg32, const unsigned char *sig64, const secp256k1_pubkey_t *pubkey) {
+    secp256k1_ge_t q;
+    ARG_CHECK(ctx != NULL);
+    ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx));
+    ARG_CHECK(msg32 != NULL);
+    ARG_CHECK(sig64 != NULL);
+    ARG_CHECK(pubkey != NULL);
+
+    secp256k1_pubkey_load(ctx, &q, pubkey);
+    return secp256k1_schnorr_sig_verify(&ctx->ecmult_ctx, sig64, &q, secp256k1_schnorr_msghash_sha256, msg32);
+}
+
+int secp256k1_schnorr_recover(const secp256k1_context_t* ctx, const unsigned char *msg32, const unsigned char *sig64, secp256k1_pubkey_t *pubkey) {
+    secp256k1_ge_t q;
+
+    ARG_CHECK(ctx != NULL);
+    ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx));
+    ARG_CHECK(msg32 != NULL);
+    ARG_CHECK(sig64 != NULL);
+    ARG_CHECK(pubkey != NULL);
+
+    if (secp256k1_schnorr_sig_recover(&ctx->ecmult_ctx, sig64, &q, secp256k1_schnorr_msghash_sha256, msg32)) {
+        secp256k1_pubkey_save(pubkey, &q);
+        return 1;
+    } else {
+        memset(pubkey, 0, sizeof(*pubkey));
+        return 0;
+    }
+}
+
+int secp256k1_schnorr_generate_nonce_pair(const secp256k1_context_t* ctx, const unsigned char *msg32, const unsigned char *sec32, secp256k1_nonce_function_t noncefp, const void* noncedata, secp256k1_pubkey_t *pubnonce, unsigned char *privnonce32) {
+    int count = 0;
+    int ret = 1;
+    secp256k1_gej_t Qj;
+    secp256k1_ge_t Q;
+    secp256k1_scalar_t sec;
+
+    ARG_CHECK(ctx != NULL);
+    ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));
+    ARG_CHECK(msg32 != NULL);
+    ARG_CHECK(sec32 != NULL);
+    ARG_CHECK(pubnonce != NULL);
+    ARG_CHECK(privnonce32 != NULL);
+
+    if (noncefp == NULL) {
+        noncefp = secp256k1_nonce_function_default;
+    }
+
+    do {
+        int overflow;
+        ret = noncefp(privnonce32, msg32, sec32, secp256k1_schnorr_algo16, count++, noncedata);
+        if (!ret) {
+            break;
+        }
+        secp256k1_scalar_set_b32(&sec, privnonce32, &overflow);
+        if (overflow || secp256k1_scalar_is_zero(&sec)) {
+            continue;
+        }
+        secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &Qj, &sec);
+        secp256k1_ge_set_gej(&Q, &Qj);
+
+        secp256k1_pubkey_save(pubnonce, &Q);
+        break;
+    } while(1);
+
+    secp256k1_scalar_clear(&sec);
+    if (!ret) {
+        memset(pubnonce, 0, sizeof(*pubnonce));
+    }
+    return ret;
+}
+
+int secp256k1_schnorr_partial_sign(const secp256k1_context_t* ctx, const unsigned char *msg32, unsigned char *sig64, const unsigned char *sec32, const unsigned char *secnonce32, const secp256k1_pubkey_t *pubnonce_others) {
+    int overflow = 0;
+    secp256k1_scalar_t sec, non;
+    secp256k1_ge_t pubnon;
+    ARG_CHECK(ctx != NULL);
+    ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));
+    ARG_CHECK(msg32 != NULL);
+    ARG_CHECK(sig64 != NULL);
+    ARG_CHECK(sec32 != NULL);
+    ARG_CHECK(secnonce32 != NULL);
+    ARG_CHECK(pubnonce_others != NULL);
+
+    secp256k1_scalar_set_b32(&sec, sec32, &overflow);
+    if (overflow || secp256k1_scalar_is_zero(&sec)) {
+        return -1;
+    }
+    secp256k1_scalar_set_b32(&non, secnonce32, &overflow);
+    if (overflow || secp256k1_scalar_is_zero(&non)) {
+        return -1;
+    }
+    secp256k1_pubkey_load(ctx, &pubnon, pubnonce_others);
+    return secp256k1_schnorr_sig_sign(&ctx->ecmult_gen_ctx, sig64, &sec, &non, &pubnon, secp256k1_schnorr_msghash_sha256, msg32);
+}
+
+int secp256k1_schnorr_partial_combine(const secp256k1_context_t* ctx, unsigned char *sig64, int n, const unsigned char * const *sig64sin) {
+    ARG_CHECK(sig64 != NULL);
+    ARG_CHECK(n >= 1);
+    ARG_CHECK(sig64sin != NULL);
+    return secp256k1_schnorr_sig_combine(sig64, n, sig64sin);
+}
+
+#endif
diff --git a/src/modules/schnorr/schnorr.h b/src/modules/schnorr/schnorr.h
new file mode 100644
index 0000000000..34311ab0bc
--- /dev/null
+++ b/src/modules/schnorr/schnorr.h
@@ -0,0 +1,20 @@
+/***********************************************************************
+ * Copyright (c) 2014-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or http://www.opensource.org/licenses/mit-license.php. *
+ ***********************************************************************/
+
+#ifndef _SECP256K1_SCHNORR_
+#define _SECP256K1_SCHNORR_
+
+#include "scalar.h"
+#include "group.h"
+
+typedef void (*secp256k1_schnorr_msghash_t)(unsigned char *h32, const unsigned char *r32, const unsigned char *msg32);
+
+static int secp256k1_schnorr_sig_sign(const secp256k1_ecmult_gen_context_t* ctx, unsigned char *sig64, const secp256k1_scalar_t *key, const secp256k1_scalar_t *nonce, const secp256k1_ge_t *pubnonce, secp256k1_schnorr_msghash_t hash, const unsigned char *msg32);
+static int secp256k1_schnorr_sig_verify(const secp256k1_ecmult_context_t* ctx, const unsigned char *sig64, const secp256k1_ge_t *pubkey, secp256k1_schnorr_msghash_t hash, const unsigned char *msg32);
+static int secp256k1_schnorr_sig_recover(const secp256k1_ecmult_context_t* ctx, const unsigned char *sig64, secp256k1_ge_t *pubkey, secp256k1_schnorr_msghash_t hash, const unsigned char *msg32);
+static int secp256k1_schnorr_sig_combine(unsigned char *sig64, int n, const unsigned char * const *sig64ins);
+
+#endif
diff --git a/src/modules/schnorr/schnorr_impl.h b/src/modules/schnorr/schnorr_impl.h
new file mode 100644
index 0000000000..e8e971fa93
--- /dev/null
+++ b/src/modules/schnorr/schnorr_impl.h
@@ -0,0 +1,207 @@
+/***********************************************************************
+ * Copyright (c) 2014-2015 Pieter Wuille                               *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or http://www.opensource.org/licenses/mit-license.php. *
+ ***********************************************************************/
+
+#ifndef _SECP256K1_SCHNORR_IMPL_H_
+#define _SECP256K1_SCHNORR_IMPL_H_
+
+#include <string.h>
+
+#include "schnorr.h"
+#include "num.h"
+#include "field.h"
+#include "group.h"
+#include "ecmult.h"
+#include "ecmult_gen.h"
+
+/**
+ * Custom Schnorr-based signature scheme. They support multiparty signing, public key
+ * recovery and batch validation.
+ *
+ * Rationale for verifying R's y coordinate:
+ * In order to support batch validation and public key recovery, the full R point must
+ * be known to verifiers, rather than just its x coordinate. In order to not risk
+ * being more strict in batch validation than normal validation, validators must be
+ * required to reject signatures with incorrect y coordinate. This is only possible
+ * by including a (relatively slow) field inverse, or a field square root. However,
+ * batch validation offers potentially much higher benefits than this cost.
+ *
+ * Rationale for having an implicit y coordinate oddness:
+ * If we commit to having the full R point known to verifiers, there are two mechanism.
+ * Either include its oddness in the signature, or give it an implicit fixed value.
+ * As the R y coordinate can be flipped by a simple negation of the nonce, we choose the
+ * latter, as it comes with nearly zero impact on signing or validation performance, and
+ * saves a byte in the signature.
+ *
+ * Signing:
+ *   Inputs: 32-byte message m, 32-byte scalar key x (!=0), 32-byte scalar nonce k (!=0)
+ *
+ *   Compute point R = k * G. Reject nonce if R's y coordinate is odd (or negate nonce).
+ *   Compute 32-byte r, the serialization of R's x coordinate.
+ *   Compute scalar h = Hash(r || m). Reject nonce if h == 0 or h >= order.
+ *   Compute scalar s = k - h * x.
+ *   The signature is (r, s).
+ *
+ *
+ * Verification:
+ *   Inputs: 32-byte message m, public key point Q, signature: (32-byte r, scalar s)
+ *
+ *   Signature is invalid if s >= order.
+ *   Signature is invalid if r >= p.
+ *   Compute scalar h = Hash(r || m). Signature is invalid if h == 0 or h >= order.
+ *   Option 1 (faster for single verification):
+ *     Compute point R = h * Q + s * G. Signature is invalid if R is infinity or R's y coordinate is odd.
+ *     Signature is valid if the serialization of R's x coordinate equals r.
+ *   Option 2 (allows batch validation and pubkey recovery):
+ *     Decompress x coordinate r into point R, with odd y coordinate. Fail if R is not on the curve.
+ *     Signature is valid if R + h * Q + s * G == 0.
+ */
+
+static int secp256k1_schnorr_sig_sign(const secp256k1_ecmult_gen_context_t* ctx, unsigned char *sig64, const secp256k1_scalar_t *key, const secp256k1_scalar_t *nonce, const secp256k1_ge_t *pubnonce, secp256k1_schnorr_msghash_t hash, const unsigned char *msg32) {
+    secp256k1_gej_t Rj;
+    secp256k1_ge_t Ra;
+    unsigned char h32[32];
+    secp256k1_scalar_t h, s;
+    int overflow;
+    secp256k1_scalar_t n;
+
+    if (secp256k1_scalar_is_zero(key) || secp256k1_scalar_is_zero(nonce)) {
+        return 0;
+    }
+    n = *nonce;
+
+    secp256k1_ecmult_gen(ctx, &Rj, &n);
+    if (pubnonce) {
+        secp256k1_gej_add_ge(&Rj, &Rj, pubnonce);
+    }
+    secp256k1_ge_set_gej(&Ra, &Rj);
+    secp256k1_fe_normalize(&Ra.y);
+    if (secp256k1_fe_is_odd(&Ra.y)) {
+        /* R's y coordinate is odd, which is not allowed (see rationale above).
+           Force it to be even by negating the nonce. Note that this even works
+           for multiparty signing, as the R point is known to all participants,
+           which can all decide to flip the sign in unison, resulting in the
+           overall R point to be negated too. */
+        secp256k1_scalar_negate(&n, &n);
+    }
+    secp256k1_fe_normalize(&Ra.x);
+    secp256k1_fe_get_b32(sig64, &Ra.x);
+    hash(h32, sig64, msg32);
+    overflow = 0;
+    secp256k1_scalar_set_b32(&h, h32, &overflow);
+    if (overflow || secp256k1_scalar_is_zero(&h)) {
+        secp256k1_scalar_clear(&n);
+        return 0;
+    }
+    secp256k1_scalar_mul(&s, &h, key);
+    secp256k1_scalar_negate(&s, &s);
+    secp256k1_scalar_add(&s, &s, &n);
+    secp256k1_scalar_clear(&n);
+    secp256k1_scalar_get_b32(sig64 + 32, &s);
+    return 1;
+}
+
+static int secp256k1_schnorr_sig_verify(const secp256k1_ecmult_context_t* ctx, const unsigned char *sig64, const secp256k1_ge_t *pubkey, secp256k1_schnorr_msghash_t hash, const unsigned char *msg32) {
+    secp256k1_gej_t Qj, Rj;
+    secp256k1_ge_t Ra;
+    secp256k1_fe_t Rx;
+    secp256k1_scalar_t h, s;
+    unsigned char hh[32];
+    int overflow;
+
+    if (secp256k1_ge_is_infinity(pubkey)) {
+        return 0;
+    }
+    hash(hh, sig64, msg32);
+    overflow = 0;
+    secp256k1_scalar_set_b32(&h, hh, &overflow);
+    if (overflow || secp256k1_scalar_is_zero(&h)) {
+        return 0;
+    }
+    overflow = 0;
+    secp256k1_scalar_set_b32(&s, sig64 + 32, &overflow);
+    if (overflow) {
+        return 0;
+    }
+    if (!secp256k1_fe_set_b32(&Rx, sig64)) {
+        return 0;
+    }
+    secp256k1_gej_set_ge(&Qj, pubkey);
+    secp256k1_ecmult(ctx, &Rj, &Qj, &h, &s);
+    if (secp256k1_gej_is_infinity(&Rj)) {
+        return 0;
+    }
+    secp256k1_ge_set_gej_var(&Ra, &Rj);
+    secp256k1_fe_normalize_var(&Ra.y);
+    if (secp256k1_fe_is_odd(&Ra.y)) {
+        return 0;
+    }
+    return secp256k1_fe_equal_var(&Rx, &Ra.x);
+}
+
+static int secp256k1_schnorr_sig_recover(const secp256k1_ecmult_context_t* ctx, const unsigned char *sig64, secp256k1_ge_t *pubkey, secp256k1_schnorr_msghash_t hash, const unsigned char *msg32) {
+    secp256k1_gej_t Qj, Rj;
+    secp256k1_ge_t Ra;
+    secp256k1_fe_t Rx;
+    secp256k1_scalar_t h, s;
+    unsigned char hh[32];
+    int overflow;
+
+    hash(hh, sig64, msg32);
+    overflow = 0;
+    secp256k1_scalar_set_b32(&h, hh, &overflow);
+    if (overflow || secp256k1_scalar_is_zero(&h)) {
+        return 0;
+    }
+    overflow = 0;
+    secp256k1_scalar_set_b32(&s, sig64 + 32, &overflow);
+    if (overflow) {
+        return 0;
+    }
+    if (!secp256k1_fe_set_b32(&Rx, sig64)) {
+        return 0;
+    }
+    if (!secp256k1_ge_set_xo_var(&Ra, &Rx, 0)) {
+        return 0;
+    }
+    secp256k1_gej_set_ge(&Rj, &Ra);
+    secp256k1_scalar_inverse_var(&h, &h);
+    secp256k1_scalar_negate(&s, &s);
+    secp256k1_scalar_mul(&s, &s, &h);
+    secp256k1_ecmult(ctx, &Qj, &Rj, &h, &s);
+    if (secp256k1_gej_is_infinity(&Qj)) {
+        return 0;
+    }
+    secp256k1_ge_set_gej(pubkey, &Qj);
+    return 1;
+}
+
+static int secp256k1_schnorr_sig_combine(unsigned char *sig64, int n, const unsigned char * const *sig64ins) {
+    secp256k1_scalar_t s = SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 0);
+    int i;
+    for (i = 0; i < n; i++) {
+        secp256k1_scalar_t si;
+        int overflow;
+        secp256k1_scalar_set_b32(&si, sig64ins[i] + 32, &overflow);
+        if (overflow) {
+            return -1;
+        }
+        if (i) {
+            if (memcmp(sig64ins[i - 1], sig64ins[i], 32) != 0) {
+                return -1;
+            }
+        }
+        secp256k1_scalar_add(&s, &s, &si);
+    }
+    if (secp256k1_scalar_is_zero(&s)) {
+        return 0;
+    }
+    memcpy(sig64, sig64ins[0], 32);
+    secp256k1_scalar_get_b32(sig64 + 32, &s);
+    secp256k1_scalar_clear(&s);
+    return 1;
+}
+
+#endif
diff --git a/src/modules/schnorr/tests_impl.h b/src/modules/schnorr/tests_impl.h
new file mode 100644
index 0000000000..402eb63b25
--- /dev/null
+++ b/src/modules/schnorr/tests_impl.h
@@ -0,0 +1,173 @@
+/**********************************************************************
+ * Copyright (c) 2014-2015 Pieter Wuille                              *
+ * Distributed under the MIT software license, see the accompanying   *
+ * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
+ **********************************************************************/
+
+#ifndef SECP256K1_MODULE_SCHNORR_TESTS
+#define SECP256K1_MODULE_SCHNORR_TESTS
+
+void test_schnorr_end_to_end(void) {
+    unsigned char privkey[32];
+    unsigned char message[32];
+    unsigned char schnorr_signature[64];
+    secp256k1_pubkey_t pubkey, recpubkey;
+
+    /* Generate a random key and message. */
+    {
+        secp256k1_scalar_t key;
+        random_scalar_order_test(&key);
+        secp256k1_scalar_get_b32(privkey, &key);
+        secp256k1_rand256_test(message);
+    }
+
+    /* Construct and verify corresponding public key. */
+    CHECK(secp256k1_ec_seckey_verify(ctx, privkey) == 1);
+    CHECK(secp256k1_ec_pubkey_create(ctx, &pubkey, privkey) == 1);
+
+    /* Schnorr sign. */
+    CHECK(secp256k1_schnorr_sign(ctx, message, schnorr_signature, privkey, NULL, NULL) == 1);
+    CHECK(secp256k1_schnorr_verify(ctx, message, schnorr_signature, &pubkey) == 1);
+    CHECK(secp256k1_schnorr_recover(ctx, message, schnorr_signature, &recpubkey) == 1);
+    CHECK(memcmp(&pubkey, &recpubkey, sizeof(pubkey)) == 0);
+    /* Destroy signature and verify again. */
+    schnorr_signature[secp256k1_rand32() % 64] += 1 + (secp256k1_rand32() % 255);
+    CHECK(secp256k1_schnorr_verify(ctx, message, schnorr_signature, &pubkey) == 0);
+    CHECK(secp256k1_schnorr_recover(ctx, message, schnorr_signature, &recpubkey) != 1 ||
+          memcmp(&pubkey, &recpubkey, sizeof(pubkey)) != 0);
+}
+
+/** Horribly broken hash function. Do not use for anything but tests. */
+void test_schnorr_hash(unsigned char *h32, const unsigned char *r32, const unsigned char *msg32) {
+    int i;
+    for (i = 0; i < 32; i++) {
+        h32[i] = r32[i] ^ msg32[i];
+    }
+}
+
+void test_schnorr_sign_verify(void) {
+    unsigned char msg32[32];
+    unsigned char sig64[3][64];
+    secp256k1_gej_t pubkeyj[3];
+    secp256k1_ge_t pubkey[3];
+    secp256k1_scalar_t nonce[3], key[3];
+    int i = 0;
+    int k;
+
+    secp256k1_rand256_test(msg32);
+
+    for (k = 0; k < 3; k++) {
+        random_scalar_order_test(&key[k]);
+
+        do {
+            random_scalar_order_test(&nonce[k]);
+            if (secp256k1_schnorr_sig_sign(&ctx->ecmult_gen_ctx, sig64[k], &key[k], &nonce[k], NULL, &test_schnorr_hash, msg32)) {
+                break;
+            }
+        } while(1);
+
+        secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &pubkeyj[k], &key[k]);
+        secp256k1_ge_set_gej_var(&pubkey[k], &pubkeyj[k]);
+        CHECK(secp256k1_schnorr_sig_verify(&ctx->ecmult_ctx, sig64[k], &pubkey[k], &test_schnorr_hash, msg32));
+
+        for (i = 0; i < 4; i++) {
+            int pos = secp256k1_rand32() % 64;
+            int mod = 1 + (secp256k1_rand32() % 255);
+            sig64[k][pos] ^= mod;
+            CHECK(secp256k1_schnorr_sig_verify(&ctx->ecmult_ctx, sig64[k], &pubkey[k], &test_schnorr_hash, msg32) == 0);
+            sig64[k][pos] ^= mod;
+        }
+    }
+}
+
+void test_schnorr_threshold(void) {
+    unsigned char msg[32];
+    unsigned char sec[5][32];
+    secp256k1_pubkey_t pub[5];
+    unsigned char nonce[5][32];
+    secp256k1_pubkey_t pubnonce[5];
+    unsigned char sig[5][64];
+    const unsigned char* sigs[5];
+    unsigned char allsig[64];
+    const secp256k1_pubkey_t* pubs[5];
+    secp256k1_pubkey_t allpub;
+    int n, i;
+    int damage;
+    int ret = 0;
+
+    damage = (secp256k1_rand32() % 2) ? (1 + (secp256k1_rand32() % 4)) : 0;
+    secp256k1_rand256_test(msg);
+    n = 2 + (secp256k1_rand32() % 4);
+    for (i = 0; i < n; i++) {
+        do {
+            secp256k1_rand256_test(sec[i]);
+        } while (!secp256k1_ec_seckey_verify(ctx, sec[i]));
+        CHECK(secp256k1_ec_pubkey_create(ctx, &pub[i], sec[i]));
+        CHECK(secp256k1_schnorr_generate_nonce_pair(ctx, msg, sec[i], NULL, NULL, &pubnonce[i], nonce[i]));
+        pubs[i] = &pub[i];
+    }
+    if (damage == 1) {
+        nonce[secp256k1_rand32() % n][secp256k1_rand32() % 32] ^= 1 + (secp256k1_rand32() % 255);
+    } else if (damage == 2) {
+        sec[secp256k1_rand32() % n][secp256k1_rand32() % 32] ^= 1 + (secp256k1_rand32() % 255);
+    }
+    for (i = 0; i < n; i++) {
+        secp256k1_pubkey_t allpubnonce;
+        const secp256k1_pubkey_t *pubnonces[4];
+        int j;
+        for (j = 0; j < i; j++) {
+            pubnonces[j] = &pubnonce[j];
+        }
+        for (j = i + 1; j < n; j++) {
+            pubnonces[j - 1] = &pubnonce[j];
+        }
+        CHECK(secp256k1_ec_pubkey_combine(ctx, &allpubnonce, n - 1, pubnonces));
+        ret |= (secp256k1_schnorr_partial_sign(ctx, msg, sig[i], sec[i], nonce[i], &allpubnonce) != 1) * 1;
+        sigs[i] = sig[i];
+    }
+    if (damage == 3) {
+        sig[secp256k1_rand32() % n][secp256k1_rand32() % 64] ^= 1 + (secp256k1_rand32() % 255);
+    }
+    ret |= (secp256k1_ec_pubkey_combine(ctx, &allpub, n, pubs) != 1) * 2;
+    if ((ret & 1) == 0) {
+        ret |= (secp256k1_schnorr_partial_combine(ctx, allsig, n, sigs) != 1) * 4;
+    }
+    if (damage == 4) {
+        allsig[secp256k1_rand32() % 32] ^= 1 + (secp256k1_rand32() % 255);
+    }
+    if ((ret & 7) == 0) {
+        ret |= (secp256k1_schnorr_verify(ctx, msg, allsig, &allpub) != 1) * 8;
+    }
+    CHECK((ret == 0) == (damage == 0));
+}
+
+void test_schnorr_recovery(void) {
+    unsigned char msg32[32];
+    unsigned char sig64[64];
+    secp256k1_ge_t Q;
+
+    secp256k1_rand256_test(msg32);
+    secp256k1_rand256_test(sig64);
+    secp256k1_rand256_test(sig64 + 32);
+    if (secp256k1_schnorr_sig_recover(&ctx->ecmult_ctx, sig64, &Q, &test_schnorr_hash, msg32) == 1) {
+        CHECK(secp256k1_schnorr_sig_verify(&ctx->ecmult_ctx, sig64, &Q, &test_schnorr_hash, msg32) == 1);
+    }
+}
+
+void run_schnorr_tests(void) {
+    int i;
+    for (i = 0; i < 32*count; i++) {
+        test_schnorr_end_to_end();
+    }
+    for (i = 0; i < 32 * count; i++) {
+         test_schnorr_sign_verify();
+    }
+    for (i = 0; i < 16 * count; i++) {
+         test_schnorr_recovery();
+    }
+    for (i = 0; i < 10 * count; i++) {
+         test_schnorr_threshold();
+    }
+}
+
+#endif
diff --git a/src/secp256k1.c b/src/secp256k1.c
index 9d6dee671d..4699bff802 100644
--- a/src/secp256k1.c
+++ b/src/secp256k1.c
@@ -267,20 +267,29 @@ int secp256k1_ecdsa_verify(const secp256k1_context_t* ctx, const unsigned char *
             secp256k1_ecdsa_sig_verify(&ctx->ecmult_ctx, &r, &s, &q, &m));
 }
 
-static int nonce_function_rfc6979(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, unsigned int counter, const void *data) {
-   unsigned char keydata[96];
+static int nonce_function_rfc6979(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, const unsigned char *algo16, unsigned int counter, const void *data) {
+   unsigned char keydata[112];
+   int keylen = 64;
    secp256k1_rfc6979_hmac_sha256_t rng;
    unsigned int i;
    /* We feed a byte array to the PRNG as input, consisting of:
     * - the private key (32 bytes) and message (32 bytes), see RFC 6979 3.2d.
     * - optionally 32 extra bytes of data, see RFC 6979 3.6 Additional Data.
+    * - optionally 16 extra bytes with the algorithm name (the extra data bytes
+    *   are set to zeroes when not present, while the algorithm name is).
     */
    memcpy(keydata, key32, 32);
    memcpy(keydata + 32, msg32, 32);
    if (data != NULL) {
        memcpy(keydata + 64, data, 32);
+       keylen = 96;
    }
-   secp256k1_rfc6979_hmac_sha256_initialize(&rng, keydata, data != NULL ? 96 : 64);
+   if (algo16 != NULL) {
+       memset(keydata + keylen, 0, 96 - keylen);
+       memcpy(keydata + 96, algo16, 16);
+       keylen = 112;
+   }
+   secp256k1_rfc6979_hmac_sha256_initialize(&rng, keydata, keylen);
    memset(keydata, 0, sizeof(keydata));
    for (i = 0; i <= counter; i++) {
        secp256k1_rfc6979_hmac_sha256_generate(&rng, nonce32, 32);
@@ -314,7 +323,7 @@ int secp256k1_ecdsa_sign(const secp256k1_context_t* ctx, const unsigned char *ms
         secp256k1_scalar_set_b32(&msg, msg32, NULL);
         while (1) {
             unsigned char nonce32[32];
-            ret = noncefp(nonce32, msg32, seckey, count, noncedata);
+            ret = noncefp(nonce32, msg32, seckey, NULL, count, noncedata);
             if (!ret) {
                 break;
             }
@@ -527,6 +536,34 @@ int secp256k1_context_randomize(secp256k1_context_t* ctx, const unsigned char *s
     return 1;
 }
 
+int secp256k1_ec_pubkey_combine(const secp256k1_context_t* ctx, secp256k1_pubkey_t *pubnonce, int n, const secp256k1_pubkey_t * const *pubnonces) {
+    int i;
+    secp256k1_gej_t Qj;
+    secp256k1_ge_t Q;
+
+    ARG_CHECK(pubnonce != NULL);
+    ARG_CHECK(n >= 1);
+    ARG_CHECK(pubnonces != NULL);
+
+    secp256k1_gej_set_infinity(&Qj);
+
+    for (i = 0; i < n; i++) {
+        secp256k1_pubkey_load(ctx, &Q, pubnonces[i]);
+        secp256k1_gej_add_ge(&Qj, &Qj, &Q);
+    }
+    if (secp256k1_gej_is_infinity(&Qj)) {
+        memset(pubnonce, 0, sizeof(*pubnonce));
+        return 0;
+    }
+    secp256k1_ge_set_gej(&Q, &Qj);
+    secp256k1_pubkey_save(pubnonce, &Q);
+    return 1;
+}
+
 #ifdef ENABLE_MODULE_ECDH
 # include "modules/ecdh/main_impl.h"
 #endif
+
+#ifdef ENABLE_MODULE_SCHNORR
+# include "modules/schnorr/main_impl.h"
+#endif
diff --git a/src/tests.c b/src/tests.c
index feb9576330..ca055c4809 100644
--- a/src/tests.c
+++ b/src/tests.c
@@ -1271,6 +1271,38 @@ void run_ge(void) {
     test_add_neg_y_diff_x();
 }
 
+void test_ec_combine(void) {
+    secp256k1_scalar_t sum = SECP256K1_SCALAR_CONST(0, 0, 0, 0, 0, 0, 0, 0);
+    secp256k1_pubkey_t data[6];
+    const secp256k1_pubkey_t* d[6];
+    secp256k1_pubkey_t sd;
+    secp256k1_pubkey_t sd2;
+    secp256k1_gej_t Qj;
+    secp256k1_ge_t Q;
+    int i;
+    for (i = 1; i <= 6; i++) {
+        secp256k1_scalar_t s;
+        random_scalar_order_test(&s);
+        secp256k1_scalar_add(&sum, &sum, &s);
+        secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &Qj, &s);
+        secp256k1_ge_set_gej(&Q, &Qj);
+        secp256k1_pubkey_save(&data[i - 1], &Q);
+        d[i - 1] = &data[i - 1];
+        secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &Qj, &sum);
+        secp256k1_ge_set_gej(&Q, &Qj);
+        secp256k1_pubkey_save(&sd, &Q);
+        CHECK(secp256k1_ec_pubkey_combine(ctx, &sd2, i, d) == 1);
+        CHECK(memcmp(&sd, &sd2, sizeof(sd)) == 0);
+    }
+}
+
+void run_ec_combine(void) {
+    int i;
+    for (i = 0; i < count * 8; i++) {
+         test_ec_combine();
+    }
+}
+
 /***** ECMULT TESTS *****/
 
 void run_ecmult_chain(void) {
@@ -1755,22 +1787,23 @@ void run_ecdsa_sign_verify(void) {
 }
 
 /** Dummy nonce generation function that just uses a precomputed nonce, and fails if it is not accepted. Use only for testing. */
-static int precomputed_nonce_function(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, unsigned int counter, const void *data) {
+static int precomputed_nonce_function(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, const unsigned char *algo16, unsigned int counter, const void *data) {
     (void)msg32;
     (void)key32;
+    (void)algo16;
     memcpy(nonce32, data, 32);
     return (counter == 0);
 }
 
-static int nonce_function_test_fail(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, unsigned int counter, const void *data) {
+static int nonce_function_test_fail(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, const unsigned char *algo16, unsigned int counter, const void *data) {
    /* Dummy nonce generator that has a fatal error on the first counter value. */
    if (counter == 0) {
        return 0;
    }
-   return nonce_function_rfc6979(nonce32, msg32, key32, counter - 1, data);
+   return nonce_function_rfc6979(nonce32, msg32, key32, algo16, counter - 1, data);
 }
 
-static int nonce_function_test_retry(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, unsigned int counter, const void *data) {
+static int nonce_function_test_retry(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, const unsigned char *algo16, unsigned int counter, const void *data) {
    /* Dummy nonce generator that produces unacceptable nonces for the first several counter values. */
    if (counter < 3) {
        memset(nonce32, counter==0 ? 0 : 255, 32);
@@ -1797,7 +1830,7 @@ static int nonce_function_test_retry(unsigned char *nonce32, const unsigned char
    if (counter > 5) {
        return 0;
    }
-   return nonce_function_rfc6979(nonce32, msg32, key32, counter - 5, data);
+   return nonce_function_rfc6979(nonce32, msg32, key32, algo16, counter - 5, data);
 }
 
 int is_empty_signature(const secp256k1_ecdsa_signature_t *sig) {
@@ -2378,6 +2411,10 @@ void run_ecdsa_openssl(void) {
 # include "modules/ecdh/tests_impl.h"
 #endif
 
+#ifdef ENABLE_MODULE_SCHNORR
+# include "modules/schnorr/tests_impl.h"
+#endif
+
 int main(int argc, char **argv) {
     unsigned char seed16[16] = {0};
     unsigned char run32[32] = {0};
@@ -2460,6 +2497,7 @@ int main(int argc, char **argv) {
     run_ecmult_constants();
     run_ecmult_gen_blind();
     run_ecmult_const_tests();
+    run_ec_combine();
 
     /* endomorphism tests */
 #ifdef USE_ENDOMORPHISM
@@ -2480,6 +2518,11 @@ int main(int argc, char **argv) {
     run_ecdsa_openssl();
 #endif
 
+#ifdef ENABLE_MODULE_SCHNORR
+    /* Schnorr tests */
+    run_schnorr_tests();
+#endif
+
     secp256k1_rand256(run32);
     printf("random run = %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n", run32[0], run32[1], run32[2], run32[3], run32[4], run32[5], run32[6], run32[7], run32[8], run32[9], run32[10], run32[11], run32[12], run32[13], run32[14], run32[15]);