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plugeth/crypto/secp256k1/libsecp256k1/src/secp256k1.c
Felix Lange e0ceeab0d1 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
2017-01-12 21:29:11 +01:00

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/**********************************************************************
* 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) {
(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) {
(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
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