diff options
Diffstat (limited to 'crypto/secp256k1/libsecp256k1/src/secp256k1.c')
| -rw-r--r-- | crypto/secp256k1/libsecp256k1/src/secp256k1.c | 559 |
1 files changed, 559 insertions, 0 deletions
diff --git a/crypto/secp256k1/libsecp256k1/src/secp256k1.c b/crypto/secp256k1/libsecp256k1/src/secp256k1.c new file mode 100644 index 000000000..7d637bfad --- /dev/null +++ b/crypto/secp256k1/libsecp256k1/src/secp256k1.c @@ -0,0 +1,559 @@ +/********************************************************************** + * Copyright (c) 2013-2015 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or http://www.opensource.org/licenses/mit-license.php.* + **********************************************************************/ + +#include "include/secp256k1.h" + +#include "util.h" +#include "num_impl.h" +#include "field_impl.h" +#include "scalar_impl.h" +#include "group_impl.h" +#include "ecmult_impl.h" +#include "ecmult_const_impl.h" +#include "ecmult_gen_impl.h" +#include "ecdsa_impl.h" +#include "eckey_impl.h" +#include "hash_impl.h" + +#define ARG_CHECK(cond) do { \ + if (EXPECT(!(cond), 0)) { \ + secp256k1_callback_call(&ctx->illegal_callback, #cond); \ + return 0; \ + } \ +} while(0) + +static void default_illegal_callback_fn(const char* str, void* data) { + fprintf(stderr, "[libsecp256k1] illegal argument: %s\n", str); + abort(); +} + +static const secp256k1_callback default_illegal_callback = { + default_illegal_callback_fn, + NULL +}; + +static void default_error_callback_fn(const char* str, void* data) { + fprintf(stderr, "[libsecp256k1] internal consistency check failed: %s\n", str); + abort(); +} + +static const secp256k1_callback default_error_callback = { + default_error_callback_fn, + NULL +}; + + +struct secp256k1_context_struct { + secp256k1_ecmult_context ecmult_ctx; + secp256k1_ecmult_gen_context ecmult_gen_ctx; + secp256k1_callback illegal_callback; + secp256k1_callback error_callback; +}; + +secp256k1_context* secp256k1_context_create(unsigned int flags) { + secp256k1_context* ret = (secp256k1_context*)checked_malloc(&default_error_callback, sizeof(secp256k1_context)); + ret->illegal_callback = default_illegal_callback; + ret->error_callback = default_error_callback; + + if (EXPECT((flags & SECP256K1_FLAGS_TYPE_MASK) != SECP256K1_FLAGS_TYPE_CONTEXT, 0)) { + secp256k1_callback_call(&ret->illegal_callback, + "Invalid flags"); + free(ret); + return NULL; + } + + secp256k1_ecmult_context_init(&ret->ecmult_ctx); + secp256k1_ecmult_gen_context_init(&ret->ecmult_gen_ctx); + + if (flags & SECP256K1_FLAGS_BIT_CONTEXT_SIGN) { + secp256k1_ecmult_gen_context_build(&ret->ecmult_gen_ctx, &ret->error_callback); + } + if (flags & SECP256K1_FLAGS_BIT_CONTEXT_VERIFY) { + secp256k1_ecmult_context_build(&ret->ecmult_ctx, &ret->error_callback); + } + + return ret; +} + +secp256k1_context* secp256k1_context_clone(const secp256k1_context* ctx) { + secp256k1_context* ret = (secp256k1_context*)checked_malloc(&ctx->error_callback, sizeof(secp256k1_context)); + ret->illegal_callback = ctx->illegal_callback; + ret->error_callback = ctx->error_callback; + secp256k1_ecmult_context_clone(&ret->ecmult_ctx, &ctx->ecmult_ctx, &ctx->error_callback); + secp256k1_ecmult_gen_context_clone(&ret->ecmult_gen_ctx, &ctx->ecmult_gen_ctx, &ctx->error_callback); + return ret; +} + +void secp256k1_context_destroy(secp256k1_context* ctx) { + if (ctx != NULL) { + secp256k1_ecmult_context_clear(&ctx->ecmult_ctx); + secp256k1_ecmult_gen_context_clear(&ctx->ecmult_gen_ctx); + + free(ctx); + } +} + +void secp256k1_context_set_illegal_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) { + if (fun == NULL) { + fun = default_illegal_callback_fn; + } + ctx->illegal_callback.fn = fun; + ctx->illegal_callback.data = data; +} + +void secp256k1_context_set_error_callback(secp256k1_context* ctx, void (*fun)(const char* message, void* data), const void* data) { + if (fun == NULL) { + fun = default_error_callback_fn; + } + ctx->error_callback.fn = fun; + ctx->error_callback.data = data; +} + +static int secp256k1_pubkey_load(const secp256k1_context* ctx, secp256k1_ge* ge, const secp256k1_pubkey* pubkey) { + if (sizeof(secp256k1_ge_storage) == 64) { + /* When the secp256k1_ge_storage type is exactly 64 byte, use its + * representation inside secp256k1_pubkey, as conversion is very fast. + * Note that secp256k1_pubkey_save must use the same representation. */ + secp256k1_ge_storage s; + memcpy(&s, &pubkey->data[0], 64); + secp256k1_ge_from_storage(ge, &s); + } else { + /* Otherwise, fall back to 32-byte big endian for X and Y. */ + secp256k1_fe x, y; + secp256k1_fe_set_b32(&x, pubkey->data); + secp256k1_fe_set_b32(&y, pubkey->data + 32); + secp256k1_ge_set_xy(ge, &x, &y); + } + ARG_CHECK(!secp256k1_fe_is_zero(&ge->x)); + return 1; +} + +static void secp256k1_pubkey_save(secp256k1_pubkey* pubkey, secp256k1_ge* ge) { + if (sizeof(secp256k1_ge_storage) == 64) { + secp256k1_ge_storage s; + secp256k1_ge_to_storage(&s, ge); + memcpy(&pubkey->data[0], &s, 64); + } else { + VERIFY_CHECK(!secp256k1_ge_is_infinity(ge)); + secp256k1_fe_normalize_var(&ge->x); + secp256k1_fe_normalize_var(&ge->y); + secp256k1_fe_get_b32(pubkey->data, &ge->x); + secp256k1_fe_get_b32(pubkey->data + 32, &ge->y); + } +} + +int secp256k1_ec_pubkey_parse(const secp256k1_context* ctx, secp256k1_pubkey* pubkey, const unsigned char *input, size_t inputlen) { + secp256k1_ge Q; + + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(pubkey != NULL); + memset(pubkey, 0, sizeof(*pubkey)); + ARG_CHECK(input != NULL); + if (!secp256k1_eckey_pubkey_parse(&Q, input, inputlen)) { + return 0; + } + secp256k1_pubkey_save(pubkey, &Q); + secp256k1_ge_clear(&Q); + return 1; +} + +int secp256k1_ec_pubkey_serialize(const secp256k1_context* ctx, unsigned char *output, size_t *outputlen, const secp256k1_pubkey* pubkey, unsigned int flags) { + secp256k1_ge Q; + size_t len; + int ret = 0; + + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(outputlen != NULL); + ARG_CHECK(*outputlen >= ((flags & SECP256K1_FLAGS_BIT_COMPRESSION) ? 33 : 65)); + len = *outputlen; + *outputlen = 0; + ARG_CHECK(output != NULL); + memset(output, 0, len); + ARG_CHECK(pubkey != NULL); + ARG_CHECK((flags & SECP256K1_FLAGS_TYPE_MASK) == SECP256K1_FLAGS_TYPE_COMPRESSION); + if (secp256k1_pubkey_load(ctx, &Q, pubkey)) { + ret = secp256k1_eckey_pubkey_serialize(&Q, output, &len, flags & SECP256K1_FLAGS_BIT_COMPRESSION); + if (ret) { + *outputlen = len; + } + } + return ret; +} + +static void secp256k1_ecdsa_signature_load(const secp256k1_context* ctx, secp256k1_scalar* r, secp256k1_scalar* s, const secp256k1_ecdsa_signature* sig) { + (void)ctx; + if (sizeof(secp256k1_scalar) == 32) { + /* When the secp256k1_scalar type is exactly 32 byte, use its + * representation inside secp256k1_ecdsa_signature, as conversion is very fast. + * Note that secp256k1_ecdsa_signature_save must use the same representation. */ + memcpy(r, &sig->data[0], 32); + memcpy(s, &sig->data[32], 32); + } else { + secp256k1_scalar_set_b32(r, &sig->data[0], NULL); + secp256k1_scalar_set_b32(s, &sig->data[32], NULL); + } +} + +static void secp256k1_ecdsa_signature_save(secp256k1_ecdsa_signature* sig, const secp256k1_scalar* r, const secp256k1_scalar* s) { + if (sizeof(secp256k1_scalar) == 32) { + memcpy(&sig->data[0], r, 32); + memcpy(&sig->data[32], s, 32); + } else { + secp256k1_scalar_get_b32(&sig->data[0], r); + secp256k1_scalar_get_b32(&sig->data[32], s); + } +} + +int secp256k1_ecdsa_signature_parse_der(const secp256k1_context* ctx, secp256k1_ecdsa_signature* sig, const unsigned char *input, size_t inputlen) { + secp256k1_scalar r, s; + + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(sig != NULL); + ARG_CHECK(input != NULL); + + if (secp256k1_ecdsa_sig_parse(&r, &s, input, inputlen)) { + secp256k1_ecdsa_signature_save(sig, &r, &s); + return 1; + } else { + memset(sig, 0, sizeof(*sig)); + return 0; + } +} + +int secp256k1_ecdsa_signature_parse_compact(const secp256k1_context* ctx, secp256k1_ecdsa_signature* sig, const unsigned char *input64) { + secp256k1_scalar r, s; + int ret = 1; + int overflow = 0; + + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(sig != NULL); + ARG_CHECK(input64 != NULL); + + secp256k1_scalar_set_b32(&r, &input64[0], &overflow); + ret &= !overflow; + secp256k1_scalar_set_b32(&s, &input64[32], &overflow); + ret &= !overflow; + if (ret) { + secp256k1_ecdsa_signature_save(sig, &r, &s); + } else { + memset(sig, 0, sizeof(*sig)); + } + return ret; +} + +int secp256k1_ecdsa_signature_serialize_der(const secp256k1_context* ctx, unsigned char *output, size_t *outputlen, const secp256k1_ecdsa_signature* sig) { + secp256k1_scalar r, s; + + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(output != NULL); + ARG_CHECK(outputlen != NULL); + ARG_CHECK(sig != NULL); + + secp256k1_ecdsa_signature_load(ctx, &r, &s, sig); + return secp256k1_ecdsa_sig_serialize(output, outputlen, &r, &s); +} + +int secp256k1_ecdsa_signature_serialize_compact(const secp256k1_context* ctx, unsigned char *output64, const secp256k1_ecdsa_signature* sig) { + secp256k1_scalar r, s; + + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(output64 != NULL); + ARG_CHECK(sig != NULL); + + secp256k1_ecdsa_signature_load(ctx, &r, &s, sig); + secp256k1_scalar_get_b32(&output64[0], &r); + secp256k1_scalar_get_b32(&output64[32], &s); + return 1; +} + +int secp256k1_ecdsa_signature_normalize(const secp256k1_context* ctx, secp256k1_ecdsa_signature *sigout, const secp256k1_ecdsa_signature *sigin) { + secp256k1_scalar r, s; + int ret = 0; + + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(sigin != NULL); + + secp256k1_ecdsa_signature_load(ctx, &r, &s, sigin); + ret = secp256k1_scalar_is_high(&s); + if (sigout != NULL) { + if (ret) { + secp256k1_scalar_negate(&s, &s); + } + secp256k1_ecdsa_signature_save(sigout, &r, &s); + } + + return ret; +} + +int secp256k1_ecdsa_verify(const secp256k1_context* ctx, const secp256k1_ecdsa_signature *sig, const unsigned char *msg32, const secp256k1_pubkey *pubkey) { + secp256k1_ge q; + secp256k1_scalar r, s; + secp256k1_scalar m; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); + ARG_CHECK(msg32 != NULL); + ARG_CHECK(sig != NULL); + ARG_CHECK(pubkey != NULL); + + secp256k1_scalar_set_b32(&m, msg32, NULL); + secp256k1_ecdsa_signature_load(ctx, &r, &s, sig); + return (!secp256k1_scalar_is_high(&s) && + secp256k1_pubkey_load(ctx, &q, pubkey) && + 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, const unsigned char *algo16, void *data, unsigned int counter) { + 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. + * Because the arguments have distinct fixed lengths it is not possible for + * different argument mixtures to emulate each other and result in the same + * nonces. + */ + memcpy(keydata, key32, 32); + memcpy(keydata + 32, msg32, 32); + if (data != NULL) { + memcpy(keydata + 64, data, 32); + keylen = 96; + } + if (algo16 != NULL) { + memcpy(keydata + keylen, algo16, 16); + keylen += 16; + } + 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); + } + secp256k1_rfc6979_hmac_sha256_finalize(&rng); + return 1; +} + +const secp256k1_nonce_function secp256k1_nonce_function_rfc6979 = nonce_function_rfc6979; +const secp256k1_nonce_function secp256k1_nonce_function_default = nonce_function_rfc6979; + +int secp256k1_ecdsa_sign(const secp256k1_context* ctx, secp256k1_ecdsa_signature *signature, const unsigned char *msg32, const unsigned char *seckey, secp256k1_nonce_function noncefp, const void* noncedata) { + secp256k1_scalar r, s; + secp256k1_scalar sec, non, msg; + int ret = 0; + int overflow = 0; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); + ARG_CHECK(msg32 != NULL); + ARG_CHECK(signature != NULL); + ARG_CHECK(seckey != NULL); + if (noncefp == NULL) { + noncefp = secp256k1_nonce_function_default; + } + + secp256k1_scalar_set_b32(&sec, seckey, &overflow); + /* Fail if the secret key is invalid. */ + if (!overflow && !secp256k1_scalar_is_zero(&sec)) { + unsigned char nonce32[32]; + unsigned int count = 0; + secp256k1_scalar_set_b32(&msg, msg32, NULL); + while (1) { + ret = noncefp(nonce32, msg32, seckey, NULL, (void*)noncedata, count); + if (!ret) { + break; + } + secp256k1_scalar_set_b32(&non, nonce32, &overflow); + if (!overflow && !secp256k1_scalar_is_zero(&non)) { + if (secp256k1_ecdsa_sig_sign(&ctx->ecmult_gen_ctx, &r, &s, &sec, &msg, &non, NULL)) { + break; + } + } + count++; + } + memset(nonce32, 0, 32); + secp256k1_scalar_clear(&msg); + secp256k1_scalar_clear(&non); + secp256k1_scalar_clear(&sec); + } + if (ret) { + secp256k1_ecdsa_signature_save(signature, &r, &s); + } else { + memset(signature, 0, sizeof(*signature)); + } + return ret; +} + +int secp256k1_ec_seckey_verify(const secp256k1_context* ctx, const unsigned char *seckey) { + secp256k1_scalar sec; + int ret; + int overflow; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(seckey != NULL); + + secp256k1_scalar_set_b32(&sec, seckey, &overflow); + ret = !overflow && !secp256k1_scalar_is_zero(&sec); + secp256k1_scalar_clear(&sec); + return ret; +} + +int secp256k1_ec_pubkey_create(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *seckey) { + secp256k1_gej pj; + secp256k1_ge p; + secp256k1_scalar sec; + int overflow; + int ret = 0; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(pubkey != NULL); + memset(pubkey, 0, sizeof(*pubkey)); + ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); + ARG_CHECK(seckey != NULL); + + secp256k1_scalar_set_b32(&sec, seckey, &overflow); + ret = (!overflow) & (!secp256k1_scalar_is_zero(&sec)); + if (ret) { + secp256k1_ecmult_gen(&ctx->ecmult_gen_ctx, &pj, &sec); + secp256k1_ge_set_gej(&p, &pj); + secp256k1_pubkey_save(pubkey, &p); + } + secp256k1_scalar_clear(&sec); + return ret; +} + +int secp256k1_ec_privkey_tweak_add(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { + secp256k1_scalar term; + secp256k1_scalar sec; + int ret = 0; + int overflow = 0; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(seckey != NULL); + ARG_CHECK(tweak != NULL); + + secp256k1_scalar_set_b32(&term, tweak, &overflow); + secp256k1_scalar_set_b32(&sec, seckey, NULL); + + ret = !overflow && secp256k1_eckey_privkey_tweak_add(&sec, &term); + memset(seckey, 0, 32); + if (ret) { + secp256k1_scalar_get_b32(seckey, &sec); + } + + secp256k1_scalar_clear(&sec); + secp256k1_scalar_clear(&term); + return ret; +} + +int secp256k1_ec_pubkey_tweak_add(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) { + secp256k1_ge p; + secp256k1_scalar term; + int ret = 0; + int overflow = 0; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); + ARG_CHECK(pubkey != NULL); + ARG_CHECK(tweak != NULL); + + secp256k1_scalar_set_b32(&term, tweak, &overflow); + ret = !overflow && secp256k1_pubkey_load(ctx, &p, pubkey); + memset(pubkey, 0, sizeof(*pubkey)); + if (ret) { + if (secp256k1_eckey_pubkey_tweak_add(&ctx->ecmult_ctx, &p, &term)) { + secp256k1_pubkey_save(pubkey, &p); + } else { + ret = 0; + } + } + + return ret; +} + +int secp256k1_ec_privkey_tweak_mul(const secp256k1_context* ctx, unsigned char *seckey, const unsigned char *tweak) { + secp256k1_scalar factor; + secp256k1_scalar sec; + int ret = 0; + int overflow = 0; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(seckey != NULL); + ARG_CHECK(tweak != NULL); + + secp256k1_scalar_set_b32(&factor, tweak, &overflow); + secp256k1_scalar_set_b32(&sec, seckey, NULL); + ret = !overflow && secp256k1_eckey_privkey_tweak_mul(&sec, &factor); + memset(seckey, 0, 32); + if (ret) { + secp256k1_scalar_get_b32(seckey, &sec); + } + + secp256k1_scalar_clear(&sec); + secp256k1_scalar_clear(&factor); + return ret; +} + +int secp256k1_ec_pubkey_tweak_mul(const secp256k1_context* ctx, secp256k1_pubkey *pubkey, const unsigned char *tweak) { + secp256k1_ge p; + secp256k1_scalar factor; + int ret = 0; + int overflow = 0; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(secp256k1_ecmult_context_is_built(&ctx->ecmult_ctx)); + ARG_CHECK(pubkey != NULL); + ARG_CHECK(tweak != NULL); + + secp256k1_scalar_set_b32(&factor, tweak, &overflow); + ret = !overflow && secp256k1_pubkey_load(ctx, &p, pubkey); + memset(pubkey, 0, sizeof(*pubkey)); + if (ret) { + if (secp256k1_eckey_pubkey_tweak_mul(&ctx->ecmult_ctx, &p, &factor)) { + secp256k1_pubkey_save(pubkey, &p); + } else { + ret = 0; + } + } + + return ret; +} + +int secp256k1_context_randomize(secp256k1_context* ctx, const unsigned char *seed32) { + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(secp256k1_ecmult_gen_context_is_built(&ctx->ecmult_gen_ctx)); + secp256k1_ecmult_gen_blind(&ctx->ecmult_gen_ctx, seed32); + return 1; +} + +int secp256k1_ec_pubkey_combine(const secp256k1_context* ctx, secp256k1_pubkey *pubnonce, const secp256k1_pubkey * const *pubnonces, size_t n) { + size_t i; + secp256k1_gej Qj; + secp256k1_ge Q; + + ARG_CHECK(pubnonce != NULL); + memset(pubnonce, 0, sizeof(*pubnonce)); + 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)) { + 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 + +#ifdef ENABLE_MODULE_RECOVERY +# include "modules/recovery/main_impl.h" +#endif |