diff --git a/schnorr_standalone.c b/schnorr_standalone.c
new file mode 100644
index 0000000..a653d1f
--- /dev/null
+++ b/schnorr_standalone.c
@@ -0,0 +1,365 @@
+/***********************************************************************
+ * Copyright (c) 2018-2020 Andrew Poelstra, Jonas Nick                 *
+ * Distributed under the MIT software license, see the accompanying    *
+ * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
+ ***********************************************************************/
+
+/*
+ * Standalone Schnorr Signature Implementation (BIP-340)
+ * 
+ * This file extracts the Schnorr signature functions from the secp256k1
+ * library. It contains the core signing and verification logic for BIP-340
+ * compliant Schnorr signatures.
+ *
+ * DEPENDENCIES:
+ * This implementation requires the following from secp256k1:
+ * - secp256k1_context structure (with ecmult_gen_ctx for signing)
+ * - secp256k1_scalar, secp256k1_fe, secp256k1_ge, secp256k1_gej types
+ * - Scalar operations: set_b32, set_b32_seckey, get_b32, is_zero, negate, mul, add, cmov
+ * - Field operations: set_b32_limit, get_b32, is_odd, normalize_var, equal
+ * - Group operations: set_xo_var, set_gej, set_gej_var, is_infinity, ecmult_gen, ecmult
+ * - Hash operations: sha256_initialize, sha256_write, sha256_finalize, sha256_clear, sha256_initialize_tagged
+ * - Keypair operations: keypair_load
+ * - X-only pubkey operations: xonly_pubkey_load
+ * - Utility: memcmp_var, memczero, memclear_explicit, declassify
+ *
+ * To use this file, you must link against the full secp256k1 library or
+ * provide implementations of the above dependencies.
+ */
+
+#ifndef SCHNORR_STANDALONE_C
+#define SCHNORR_STANDALONE_C
+
+#include <stdint.h>
+#include <stddef.h>
+#include <string.h>
+
+/* SHA256 structure definition (from secp256k1 hash.h) */
+typedef struct {
+    uint32_t s[8];
+    unsigned char buf[64];
+    uint64_t bytes;
+} secp256k1_sha256;
+
+/* Forward declarations - these types must be provided by secp256k1 */
+typedef struct secp256k1_context_struct secp256k1_context;
+typedef struct secp256k1_scalar_struct secp256k1_scalar;
+typedef struct secp256k1_fe_struct secp256k1_fe;
+typedef struct secp256k1_ge_struct secp256k1_ge;
+typedef struct secp256k1_gej_struct secp256k1_gej;
+typedef struct secp256k1_keypair_struct secp256k1_keypair;
+typedef struct secp256k1_xonly_pubkey_struct secp256k1_xonly_pubkey;
+
+/* Forward declarations - these functions must be provided by secp256k1 */
+extern void secp256k1_sha256_initialize(secp256k1_sha256 *hash);
+extern void secp256k1_sha256_write(secp256k1_sha256 *hash, const unsigned char *data, size_t size);
+extern void secp256k1_sha256_finalize(secp256k1_sha256 *hash, unsigned char *out32);
+extern void secp256k1_sha256_clear(secp256k1_sha256 *hash);
+extern void secp256k1_sha256_initialize_tagged(secp256k1_sha256 *hash, const unsigned char *tag, size_t taglen);
+extern int secp256k1_memcmp_var(const void *s1, const void *s2, size_t n);
+extern void secp256k1_memczero(void *s, size_t len, int flag);
+extern void secp256k1_memclear_explicit(void *ptr, size_t len);
+extern void secp256k1_declassify(const secp256k1_context *ctx, const void *ptr, size_t len);
+extern int secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *bin, int *overflow);
+extern int secp256k1_scalar_set_b32_seckey(secp256k1_scalar *r, const unsigned char *bin);
+extern void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar *a);
+extern int secp256k1_scalar_is_zero(const secp256k1_scalar *a);
+extern void secp256k1_scalar_negate(secp256k1_scalar *r, const secp256k1_scalar *a);
+extern void secp256k1_scalar_mul(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b);
+extern void secp256k1_scalar_add(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b);
+extern void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag);
+extern int secp256k1_fe_set_b32_limit(secp256k1_fe *r, const unsigned char *a);
+extern void secp256k1_fe_get_b32(unsigned char *r, const secp256k1_fe *a);
+extern int secp256k1_fe_is_odd(const secp256k1_fe *a);
+extern void secp256k1_fe_normalize_var(secp256k1_fe *r);
+extern int secp256k1_fe_equal(const secp256k1_fe *a, const secp256k1_fe *b);
+extern int secp256k1_ge_set_xo_var(secp256k1_ge *r, const secp256k1_fe *x, int odd);
+extern void secp256k1_ge_set_gej(secp256k1_ge *r, const secp256k1_gej *a);
+extern void secp256k1_ge_set_gej_var(secp256k1_ge *r, const secp256k1_gej *a);
+extern int secp256k1_ge_is_infinity(const secp256k1_ge *r);
+extern void secp256k1_ecmult_gen(const secp256k1_ecmult_gen_context *ctx, secp256k1_gej *r, const secp256k1_scalar *a);
+extern void secp256k1_ecmult(const secp256k1_ecmult_context *ctx, secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_scalar *na, const secp256k1_scalar *ng);
+extern int secp256k1_keypair_load(const secp256k1_context *ctx, secp256k1_scalar *sk, secp256k1_ge *pk, const secp256k1_keypair *keypair);
+extern int secp256k1_xonly_pubkey_load(const secp256k1_context *ctx, secp256k1_ge *ge, const secp256k1_xonly_pubkey *pubkey);
+extern int secp256k1_ecmult_gen_context_is_built(const secp256k1_ecmult_gen_context *ctx);
+extern secp256k1_scalar secp256k1_scalar_one;
+
+/* Internal context structure references */
+typedef struct secp256k1_ecmult_gen_context_struct secp256k1_ecmult_gen_context;
+typedef struct secp256k1_ecmult_context_struct secp256k1_ecmult_context;
+
+/* Macros for argument checking */
+#ifndef VERIFY_CHECK
+#define VERIFY_CHECK(cond) do { } while(0)
+#endif
+
+#ifndef ARG_CHECK
+#define ARG_CHECK(cond) do { \
+    if (!(cond)) { \
+        return 0; \
+    } \
+} while(0)
+#endif
+
+/* BIP-340 nonce tag */
+static const unsigned char bip340_algo[] = {'B', 'I', 'P', '0', '3', '4', '0', '/', 'n', 'o', 'n', 'c', 'e'};
+
+/* Extraparams magic value */
+static const unsigned char schnorrsig_extraparams_magic[4] = { 0xda, 0x6f, 0xb3, 0x8c };
+
+/* Initializes SHA256 with fixed midstate. This midstate was computed by applying
+ * SHA256 to SHA256("BIP0340/nonce")||SHA256("BIP0340/nonce"). */
+static void secp256k1_nonce_function_bip340_sha256_tagged(secp256k1_sha256 *sha) {
+    secp256k1_sha256_initialize(sha);
+    sha->s[0] = 0x46615b35ul;
+    sha->s[1] = 0xf4bfbff7ul;
+    sha->s[2] = 0x9f8dc671ul;
+    sha->s[3] = 0x83627ab3ul;
+    sha->s[4] = 0x60217180ul;
+    sha->s[5] = 0x57358661ul;
+    sha->s[6] = 0x21a29e54ul;
+    sha->s[7] = 0x68b07b4cul;
+    sha->bytes = 64;
+}
+
+/* Initializes SHA256 with fixed midstate. This midstate was computed by applying
+ * SHA256 to SHA256("BIP0340/aux")||SHA256("BIP0340/aux"). */
+static void secp256k1_nonce_function_bip340_sha256_tagged_aux(secp256k1_sha256 *sha) {
+    secp256k1_sha256_initialize(sha);
+    sha->s[0] = 0x24dd3219ul;
+    sha->s[1] = 0x4eba7e70ul;
+    sha->s[2] = 0xca0fabb9ul;
+    sha->s[3] = 0x0fa3166dul;
+    sha->s[4] = 0x3afbe4b1ul;
+    sha->s[5] = 0x4c44df97ul;
+    sha->s[6] = 0x4aac2739ul;
+    sha->s[7] = 0x249e850aul;
+    sha->bytes = 64;
+}
+
+/* BIP-340 nonce generation function */
+static int nonce_function_bip340(unsigned char *nonce32, const unsigned char *msg, size_t msglen, const unsigned char *key32, const unsigned char *xonly_pk32, const unsigned char *algo, size_t algolen, void *data) {
+    secp256k1_sha256 sha;
+    unsigned char masked_key[32];
+    int i;
+
+    if (algo == NULL) {
+        return 0;
+    }
+
+    if (data != NULL) {
+        secp256k1_nonce_function_bip340_sha256_tagged_aux(&sha);
+        secp256k1_sha256_write(&sha, data, 32);
+        secp256k1_sha256_finalize(&sha, masked_key);
+        for (i = 0; i < 32; i++) {
+            masked_key[i] ^= key32[i];
+        }
+    } else {
+        /* Precomputed TaggedHash("BIP0340/aux", 0x0000...00); */
+        static const unsigned char ZERO_MASK[32] = {
+              84, 241, 105, 207, 201, 226, 229, 114,
+             116, 128,  68,  31, 144, 186,  37, 196,
+             136, 244,  97, 199,  11,  94, 165, 220,
+             170, 247, 175, 105,  39,  10, 165,  20
+        };
+        for (i = 0; i < 32; i++) {
+            masked_key[i] = key32[i] ^ ZERO_MASK[i];
+        }
+    }
+
+    /* Tag the hash with algo which is important to avoid nonce reuse across
+     * algorithms. If this nonce function is used in BIP-340 signing as defined
+     * in the spec, an optimized tagging implementation is used. */
+    if (algolen == sizeof(bip340_algo)
+            && secp256k1_memcmp_var(algo, bip340_algo, algolen) == 0) {
+        secp256k1_nonce_function_bip340_sha256_tagged(&sha);
+    } else {
+        secp256k1_sha256_initialize_tagged(&sha, algo, algolen);
+    }
+
+    /* Hash masked-key||pk||msg using the tagged hash as per the spec */
+    secp256k1_sha256_write(&sha, masked_key, 32);
+    secp256k1_sha256_write(&sha, xonly_pk32, 32);
+    secp256k1_sha256_write(&sha, msg, msglen);
+    secp256k1_sha256_finalize(&sha, nonce32);
+    secp256k1_sha256_clear(&sha);
+    secp256k1_memclear_explicit(masked_key, sizeof(masked_key));
+
+    return 1;
+}
+
+/* Nonce function pointer type */
+typedef int (*secp256k1_nonce_function_hardened)(
+    unsigned char *nonce32,
+    const unsigned char *msg,
+    size_t msglen,
+    const unsigned char *key32,
+    const unsigned char *xonly_pk32,
+    const unsigned char *algo,
+    size_t algolen,
+    void *data
+);
+
+/* Public nonce function pointer */
+const secp256k1_nonce_function_hardened secp256k1_nonce_function_bip340 = nonce_function_bip340;
+
+/* Initializes SHA256 with fixed midstate. This midstate was computed by applying
+ * SHA256 to SHA256("BIP0340/challenge")||SHA256("BIP0340/challenge"). */
+static void secp256k1_schnorrsig_sha256_tagged(secp256k1_sha256 *sha) {
+    secp256k1_sha256_initialize(sha);
+    sha->s[0] = 0x9cecba11ul;
+    sha->s[1] = 0x23925381ul;
+    sha->s[2] = 0x11679112ul;
+    sha->s[3] = 0xd1627e0ful;
+    sha->s[4] = 0x97c87550ul;
+    sha->s[5] = 0x003cc765ul;
+    sha->s[6] = 0x90f61164ul;
+    sha->s[7] = 0x33e9b66aul;
+    sha->bytes = 64;
+}
+
+/* Compute the challenge hash e = TaggedHash("BIP0340/challenge", r || pk || msg) */
+static void secp256k1_schnorrsig_challenge(secp256k1_scalar* e, const unsigned char *r32, const unsigned char *msg, size_t msglen, const unsigned char *pubkey32)
+{
+    unsigned char buf[32];
+    secp256k1_sha256 sha;
+
+    /* tagged hash(r.x, pk.x, msg) */
+    secp256k1_schnorrsig_sha256_tagged(&sha);
+    secp256k1_sha256_write(&sha, r32, 32);
+    secp256k1_sha256_write(&sha, pubkey32, 32);
+    secp256k1_sha256_write(&sha, msg, msglen);
+    secp256k1_sha256_finalize(&sha, buf);
+    /* Set scalar e to the challenge hash modulo the curve order as per
+     * BIP340. */
+    secp256k1_scalar_set_b32(e, buf, NULL);
+}
+
+/* Internal signing function */
+static int secp256k1_schnorrsig_sign_internal(const secp256k1_context* ctx, unsigned char *sig64, const unsigned char *msg, size_t msglen, const secp256k1_keypair *keypair, secp256k1_nonce_function_hardened noncefp, void *ndata) {
+    secp256k1_scalar sk;
+    secp256k1_scalar e;
+    secp256k1_scalar k;
+    secp256k1_gej rj;
+    secp256k1_ge pk;
+    secp256k1_ge r;
+    unsigned char nonce32[32] = { 0 };
+    unsigned char pk_buf[32];
+    unsigned char seckey[32];
+    int ret = 1;
+
+    VERIFY_CHECK(ctx != NULL);
+    ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx));
+    ARG_CHECK(sig64 != NULL);
+    ARG_CHECK(msg != NULL || msglen == 0);
+    ARG_CHECK(keypair != NULL);
+
+    if (noncefp == NULL) {
+        noncefp = secp256k1_nonce_function_bip340;
+    }
+
+    ret &= secp256k1_keypair_load(ctx, &sk, &pk, keypair);
+    /* Because we are signing for a x-only pubkey, the secret key is negated
+     * before signing if the point corresponding to the secret key does not
+     * have an even Y. */
+    if (secp256k1_fe_is_odd(&pk.y)) {
+        secp256k1_scalar_negate(&sk, &sk);
+    }
+
+    secp256k1_scalar_get_b32(seckey, &sk);
+    secp256k1_fe_get_b32(pk_buf, &pk.x);
+    ret &= !!noncefp(nonce32, msg, msglen, seckey, pk_buf, bip340_algo, sizeof(bip340_algo), ndata);
+    secp256k1_scalar_set_b32(&k, nonce32, NULL);
+    ret &= !secp256k1_scalar_is_zero(&k);
+    secp256k1_scalar_cmov(&k, &secp256k1_scalar_one, !ret);
+
+    secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &rj, &k);
+    secp256k1_ge_set_gej(&r, &rj);
+
+    /* We declassify r to allow using it as a branch point. This is fine
+     * because r is not a secret. */
+    secp256k1_declassify(ctx, &r, sizeof(r));
+    secp256k1_fe_normalize_var(&r.y);
+    if (secp256k1_fe_is_odd(&r.y)) {
+        secp256k1_scalar_negate(&k, &k);
+    }
+    secp256k1_fe_normalize_var(&r.x);
+    secp256k1_fe_get_b32(&sig64[0], &r.x);
+
+    secp256k1_schnorrsig_challenge(&e, &sig64[0], msg, msglen, pk_buf);
+    secp256k1_scalar_mul(&e, &e, &sk);
+    secp256k1_scalar_add(&e, &e, &k);
+    secp256k1_scalar_get_b32(&sig64[32], &e);
+
+    secp256k1_memczero(sig64, 64, !ret);
+    secp256k1_scalar_clear(&k);
+    secp256k1_scalar_clear(&sk);
+    secp256k1_memclear_explicit(seckey, sizeof(seckey));
+    secp256k1_memclear_explicit(nonce32, sizeof(nonce32));
+    secp256k1_gej_clear(&rj);
+
+    return ret;
+}
+
+/* Public API: Sign a 32-byte message */
+int secp256k1_schnorrsig_sign32(const secp256k1_context* ctx, unsigned char *sig64, const unsigned char *msg32, const secp256k1_keypair *keypair, const unsigned char *aux_rand32) {
+    /* We cast away const from the passed aux_rand32 argument since we know the default nonce function does not modify it. */
+    return secp256k1_schnorrsig_sign_internal(ctx, sig64, msg32, 32, keypair, secp256k1_nonce_function_bip340, (unsigned char*)aux_rand32);
+}
+
+/* Public API: Verify a Schnorr signature */
+int secp256k1_schnorrsig_verify(const secp256k1_context* ctx, const unsigned char *sig64, const unsigned char *msg, size_t msglen, const secp256k1_xonly_pubkey *pubkey) {
+    secp256k1_scalar s;
+    secp256k1_scalar e;
+    secp256k1_gej rj;
+    secp256k1_ge pk;
+    secp256k1_gej pkj;
+    secp256k1_fe rx;
+    secp256k1_ge r;
+    unsigned char buf[32];
+    int overflow;
+
+    VERIFY_CHECK(ctx != NULL);
+    ARG_CHECK(sig64 != NULL);
+    ARG_CHECK(msg != NULL || msglen == 0);
+    ARG_CHECK(pubkey != NULL);
+
+    if (!secp256k1_fe_set_b32_limit(&rx, &sig64[0])) {
+        return 0;
+    }
+
+    secp256k1_scalar_set_b32(&s, &sig64[32], &overflow);
+    if (overflow) {
+        return 0;
+    }
+
+    if (!secp256k1_xonly_pubkey_load(ctx, &pk, pubkey)) {
+        return 0;
+    }
+
+    /* Compute e. */
+    secp256k1_fe_get_b32(buf, &pk.x);
+    secp256k1_schnorrsig_challenge(&e, &sig64[0], msg, msglen, buf);
+
+    /* Compute rj =  s*G + (-e)*pkj */
+    secp256k1_scalar_negate(&e, &e);
+    secp256k1_gej_set_ge(&pkj, &pk);
+    secp256k1_ecmult(&rj, &pkj, &e, &s);
+
+    secp256k1_ge_set_gej_var(&r, &rj);
+    if (secp256k1_ge_is_infinity(&r)) {
+        return 0;
+    }
+
+    secp256k1_fe_normalize_var(&r.y);
+    return !secp256k1_fe_is_odd(&r.y) &&
+           secp256k1_fe_equal(&rx, &r.x);
+}
+
+/* Additional forward declarations needed */
+extern void secp256k1_scalar_clear(secp256k1_scalar *r);
+extern void secp256k1_gej_clear(secp256k1_gej *r);
+extern void secp256k1_gej_set_ge(secp256k1_gej *r, const secp256k1_ge *a);
+
+#endif /* SCHNORR_STANDALONE_C */
+