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Fifth step in converting to C: ecdsa

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This commit is contained in:
Pieter Wuille 2013-04-01 07:21:05 +02:00
parent b1483f874c
commit d41e93a5e2
5 changed files with 107 additions and 114 deletions
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10
src/bench.cpp
View file

@ -6,8 +6,6 @@
#include "ecmult.cpp" #include "ecmult.cpp"
#include "ecdsa.cpp" #include "ecdsa.cpp"
using namespace secp256k1;
int main() { int main() {
secp256k1_num_start(); secp256k1_num_start();
secp256k1_fe_start(); secp256k1_fe_start();
@ -20,7 +18,8 @@ int main() {
secp256k1_num_init(&r); secp256k1_num_init(&r);
secp256k1_num_init(&s); secp256k1_num_init(&s);
secp256k1_num_init(&m); secp256k1_num_init(&m);
Signature sig; secp256k1_ecdsa_sig_t sig;
secp256k1_ecdsa_sig_init(&sig);
secp256k1_fe_set_hex(&x, "a357ae915c4a65281309edf20504740f0eb3343990216b4f81063cb65f2f7e0f", 64); secp256k1_fe_set_hex(&x, "a357ae915c4a65281309edf20504740f0eb3343990216b4f81063cb65f2f7e0f", 64);
int cnt = 0; int cnt = 0;
int good = 0; int good = 0;
@ -28,17 +27,18 @@ int main() {
secp256k1_num_set_rand(&r, order); secp256k1_num_set_rand(&r, order);
secp256k1_num_set_rand(&s, order); secp256k1_num_set_rand(&s, order);
secp256k1_num_set_rand(&m, order); secp256k1_num_set_rand(&m, order);
sig.SetRS(r,s); secp256k1_ecdsa_sig_set_rs(&sig, &r, &s);
secp256k1_gej_t pubkey; secp256k1_gej_set_xo(&pubkey, &x, 1); secp256k1_gej_t pubkey; secp256k1_gej_set_xo(&pubkey, &x, 1);
if (secp256k1_gej_is_valid(&pubkey)) { if (secp256k1_gej_is_valid(&pubkey)) {
cnt++; cnt++;
good += sig.Verify(pubkey, m); good += secp256k1_ecdsa_sig_verify(&sig, &pubkey, &m);
} }
} }
printf("%i/%i\n", good, cnt); printf("%i/%i\n", good, cnt);
secp256k1_num_free(&r); secp256k1_num_free(&r);
secp256k1_num_free(&s); secp256k1_num_free(&s);
secp256k1_num_free(&m); secp256k1_num_free(&m);
secp256k1_ecdsa_sig_free(&sig);
secp256k1_ecmult_stop(); secp256k1_ecmult_stop();
secp256k1_ge_stop(); secp256k1_ge_stop();

142
src/ecdsa.cpp
View file

@ -4,89 +4,99 @@
#include "ecmult.h" #include "ecmult.h"
#include "ecdsa.h" #include "ecdsa.h"
namespace secp256k1 { extern "C" {
bool ParsePubKey(secp256k1_gej_t &elem, const unsigned char *pub, int size) { void static secp256k1_ecdsa_sig_init(secp256k1_ecdsa_sig_t *r) {
secp256k1_num_init(&r->r);
secp256k1_num_init(&r->s);
}
void static secp256k1_ecdsa_sig_free(secp256k1_ecdsa_sig_t *r) {
secp256k1_num_free(&r->r);
secp256k1_num_free(&r->s);
}
int static secp256k1_ecdsa_pubkey_parse(secp256k1_gej_t *elem, const unsigned char *pub, int size) {
if (size == 33 && (pub[0] == 0x02 || pub[0] == 0x03)) { if (size == 33 && (pub[0] == 0x02 || pub[0] == 0x03)) {
secp256k1_fe_t x; secp256k1_fe_t x;
secp256k1_fe_set_b32(&x, pub+1); secp256k1_fe_set_b32(&x, pub+1);
secp256k1_gej_set_xo(&elem, &x, pub[0] == 0x03); secp256k1_gej_set_xo(elem, &x, pub[0] == 0x03);
} else if (size == 65 && (pub[0] == 0x04 || pub[0] == 0x06 || pub[0] == 0x07)) { } else if (size == 65 && (pub[0] == 0x04 || pub[0] == 0x06 || pub[0] == 0x07)) {
secp256k1_fe_t x,y; secp256k1_fe_t x, y;
secp256k1_fe_set_b32(&x, pub+1); secp256k1_fe_set_b32(&x, pub+1);
secp256k1_fe_set_b32(&y, pub+33); secp256k1_fe_set_b32(&y, pub+33);
secp256k1_gej_set_xy(&elem, &x, &y); secp256k1_gej_set_xy(elem, &x, &y);
if ((pub[0] == 0x06 || pub[0] == 0x07) && secp256k1_fe_is_odd(&y) != (pub[0] == 0x07)) if ((pub[0] == 0x06 || pub[0] == 0x07) && secp256k1_fe_is_odd(&y) != (pub[0] == 0x07))
return false; return false;
} else { } else {
return false; return false;
} }
return secp256k1_gej_is_valid(&elem); return secp256k1_gej_is_valid(elem);
} }
bool Signature::Parse(const unsigned char *sig, int size) { int static secp256k1_ecdsa_sig_parse(secp256k1_ecdsa_sig_t *r, const unsigned char *sig, int size) {
if (sig[0] != 0x30) return false; if (sig[0] != 0x30) return 0;
int lenr = sig[3]; int lenr = sig[3];
if (5+lenr >= size) return false; if (5+lenr >= size) return 0;
int lens = sig[lenr+5]; int lens = sig[lenr+5];
if (sig[1] != lenr+lens+4) return false; if (sig[1] != lenr+lens+4) return 0;
if (lenr+lens+6 > size) return false; if (lenr+lens+6 > size) return 0;
if (sig[2] != 0x02) return false; if (sig[2] != 0x02) return 0;
if (lenr == 0) return false; if (lenr == 0) return 0;
if (sig[lenr+4] != 0x02) return false; if (sig[lenr+4] != 0x02) return 0;
if (lens == 0) return false; if (lens == 0) return 0;
secp256k1_num_set_bin(&r, sig+4, lenr); secp256k1_num_set_bin(&r->r, sig+4, lenr);
secp256k1_num_set_bin(&s, sig+6+lenr, lens); secp256k1_num_set_bin(&r->s, sig+6+lenr, lens);
return true; return 1;
} }
bool Signature::Serialize(unsigned char *sig, int *size) { int static secp256k1_ecdsa_sig_serialize(unsigned char *sig, int *size, const secp256k1_ecdsa_sig_t *a) {
int lenR = (secp256k1_num_bits(&r) + 7)/8; int lenR = (secp256k1_num_bits(&a->r) + 7)/8;
if (lenR == 0 || secp256k1_num_get_bit(&r, lenR*8-1)) if (lenR == 0 || secp256k1_num_get_bit(&a->r, lenR*8-1))
lenR++; lenR++;
int lenS = (secp256k1_num_bits(&s) + 7)/8; int lenS = (secp256k1_num_bits(&a->s) + 7)/8;
if (lenS == 0 || secp256k1_num_get_bit(&s, lenS*8-1)) if (lenS == 0 || secp256k1_num_get_bit(&a->s, lenS*8-1))
lenS++; lenS++;
if (*size < 6+lenS+lenR) if (*size < 6+lenS+lenR)
return false; return 0;
*size = 6 + lenS + lenR; *size = 6 + lenS + lenR;
sig[0] = 0x30; sig[0] = 0x30;
sig[1] = 4 + lenS + lenR; sig[1] = 4 + lenS + lenR;
sig[2] = 0x02; sig[2] = 0x02;
sig[3] = lenR; sig[3] = lenR;
secp256k1_num_get_bin(sig+4, lenR, &r); secp256k1_num_get_bin(sig+4, lenR, &a->r);
sig[4+lenR] = 0x02; sig[4+lenR] = 0x02;
sig[5+lenR] = lenS; sig[5+lenR] = lenS;
secp256k1_num_get_bin(sig+lenR+6, lenS, &s); secp256k1_num_get_bin(sig+lenR+6, lenS, &a->s);
return true; return 1;
} }
bool Signature::RecomputeR(secp256k1_num_t &r2, const secp256k1_gej_t &pubkey, const secp256k1_num_t &message) const { int static secp256k1_ecdsa_sig_recompute(secp256k1_num_t *r2, const secp256k1_ecdsa_sig_t *sig, const secp256k1_gej_t *pubkey, const secp256k1_num_t *message) {
const secp256k1_ge_consts_t &c = *secp256k1_ge_consts; const secp256k1_ge_consts_t *c = secp256k1_ge_consts;
if (secp256k1_num_is_neg(&r) || secp256k1_num_is_neg(&s)) if (secp256k1_num_is_neg(&sig->r) || secp256k1_num_is_neg(&sig->s))
return false; return 0;
if (secp256k1_num_is_zero(&r) || secp256k1_num_is_zero(&s)) if (secp256k1_num_is_zero(&sig->r) || secp256k1_num_is_zero(&sig->s))
return false; return 0;
if (secp256k1_num_cmp(&r, &c.order) >= 0 || secp256k1_num_cmp(&s, &c.order) >= 0) if (secp256k1_num_cmp(&sig->r, &c->order) >= 0 || secp256k1_num_cmp(&sig->s, &c->order) >= 0)
return false; return 0;
bool ret = false; int ret = 0;
secp256k1_num_t sn, u1, u2; secp256k1_num_t sn, u1, u2;
secp256k1_num_init(&sn); secp256k1_num_init(&sn);
secp256k1_num_init(&u1); secp256k1_num_init(&u1);
secp256k1_num_init(&u2); secp256k1_num_init(&u2);
secp256k1_num_mod_inverse(&sn, &s, &c.order); secp256k1_num_mod_inverse(&sn, &sig->s, &c->order);
secp256k1_num_mod_mul(&u1, &sn, &message, &c.order); secp256k1_num_mod_mul(&u1, &sn, message, &c->order);
secp256k1_num_mod_mul(&u2, &sn, &r, &c.order); secp256k1_num_mod_mul(&u2, &sn, &sig->r, &c->order);
secp256k1_gej_t pr; secp256k1_ecmult(&pr, &pubkey, &u2, &u1); secp256k1_gej_t pr; secp256k1_ecmult(&pr, pubkey, &u2, &u1);
if (!secp256k1_gej_is_infinity(&pr)) { if (!secp256k1_gej_is_infinity(&pr)) {
secp256k1_fe_t xr; secp256k1_gej_get_x(&xr, &pr); secp256k1_fe_t xr; secp256k1_gej_get_x(&xr, &pr);
secp256k1_fe_normalize(&xr); secp256k1_fe_normalize(&xr);
unsigned char xrb[32]; secp256k1_fe_get_b32(xrb, &xr); unsigned char xrb[32]; secp256k1_fe_get_b32(xrb, &xr);
secp256k1_num_set_bin(&r2, xrb, 32); secp256k1_num_set_bin(r2, xrb, 32);
secp256k1_num_mod(&r2, &r2, &c.order); secp256k1_num_mod(r2, r2, &c->order);
ret = true; ret = 1;
} }
secp256k1_num_free(&sn); secp256k1_num_free(&sn);
secp256k1_num_free(&u1); secp256k1_num_free(&u1);
@ -94,52 +104,44 @@ bool Signature::RecomputeR(secp256k1_num_t &r2, const secp256k1_gej_t &pubkey, c
return ret; return ret;
} }
bool Signature::Verify(const secp256k1_gej_t &pubkey, const secp256k1_num_t &message) const { int secp256k1_ecdsa_sig_verify(const secp256k1_ecdsa_sig_t *sig, const secp256k1_gej_t *pubkey, const secp256k1_num_t *message) {
secp256k1_num_t r2; secp256k1_num_t r2;
secp256k1_num_init(&r2); secp256k1_num_init(&r2);
bool ret = false; int ret = 0;
ret = RecomputeR(r2, pubkey, message) && secp256k1_num_cmp(&r, &r2) == 0; ret = secp256k1_ecdsa_sig_recompute(&r2, sig, pubkey, message) && secp256k1_num_cmp(&sig->r, &r2) == 0;
secp256k1_num_free(&r2); secp256k1_num_free(&r2);
return ret; return ret;
} }
bool Signature::Sign(const secp256k1_num_t &seckey, const secp256k1_num_t &message, const secp256k1_num_t &nonce) { int static secp256k1_ecdsa_sig_sign(secp256k1_ecdsa_sig_t *sig, const secp256k1_num_t *seckey, const secp256k1_num_t *message, const secp256k1_num_t *nonce) {
const secp256k1_ge_consts_t &c = *secp256k1_ge_consts; const secp256k1_ge_consts_t *c = secp256k1_ge_consts;
secp256k1_gej_t rp; secp256k1_gej_t rp;
secp256k1_ecmult_gen(&rp, &nonce); secp256k1_ecmult_gen(&rp, nonce);
secp256k1_fe_t rx; secp256k1_fe_t rx;
secp256k1_gej_get_x(&rx, &rp); secp256k1_gej_get_x(&rx, &rp);
unsigned char b[32]; unsigned char b[32];
secp256k1_fe_normalize(&rx); secp256k1_fe_normalize(&rx);
secp256k1_fe_get_b32(b, &rx); secp256k1_fe_get_b32(b, &rx);
secp256k1_num_set_bin(&r, b, 32); secp256k1_num_set_bin(&sig->r, b, 32);
secp256k1_num_mod(&r, &r, &c.order); secp256k1_num_mod(&sig->r, &sig->r, &c->order);
secp256k1_num_t n; secp256k1_num_t n;
secp256k1_num_init(&n); secp256k1_num_init(&n);
secp256k1_num_mod_mul(&n, &r, &seckey, &c.order); secp256k1_num_mod_mul(&n, &sig->r, seckey, &c->order);
secp256k1_num_add(&n, &n, &message); secp256k1_num_add(&n, &n, message);
secp256k1_num_mod_inverse(&s, &nonce, &c.order); secp256k1_num_mod_inverse(&sig->s, nonce, &c->order);
secp256k1_num_mod_mul(&s, &s, &n, &c.order); secp256k1_num_mod_mul(&sig->s, &sig->s, &n, &c->order);
secp256k1_num_free(&n); secp256k1_num_free(&n);
if (secp256k1_num_is_zero(&s)) if (secp256k1_num_is_zero(&sig->s))
return false; return 0;
if (secp256k1_num_is_odd(&s)) if (secp256k1_num_is_odd(&sig->s))
secp256k1_num_sub(&s, &c.order, &s); secp256k1_num_sub(&sig->s, &c->order, &sig->s);
return true; return true;
} }
void Signature::SetRS(const secp256k1_num_t &rin, const secp256k1_num_t &sin) { void static secp256k1_ecdsa_sig_set_rs(secp256k1_ecdsa_sig_t *sig, const secp256k1_num_t *r, const secp256k1_num_t *s) {
secp256k1_num_copy(&r, &rin); secp256k1_num_copy(&sig->r, r);
secp256k1_num_copy(&s, &sin); secp256k1_num_copy(&sig->s, s);
}
std::string Signature::ToString() const {
char rs[65], ss[65];
int rl = 65, sl = 65;
secp256k1_num_get_hex(rs, &rl, &r);
secp256k1_num_get_hex(ss, &sl, &s);
return "(" + std::string(rs) + "," + std::string(ss) + ")";
} }
} }

34
src/ecdsa.h
View file

@ -1,30 +1,22 @@
#ifndef _SECP256K1_ECDSA_ #ifndef _SECP256K1_ECDSA_
#define _SECP256K1_ECDSA_ #define _SECP256K1_ECDSA_
namespace secp256k1 { #include "num.h"
class Signature { extern "C" {
private:
secp256k1_num_t r,s;
public: typedef struct {
Signature() { secp256k1_num_t r, s;
secp256k1_num_init(&r); } secp256k1_ecdsa_sig_t;
secp256k1_num_init(&s);
}
~Signature() {
secp256k1_num_free(&r);
secp256k1_num_free(&s);
}
bool Parse(const unsigned char *sig, int size); void static secp256k1_ecdsa_sig_init(secp256k1_ecdsa_sig_t *r);
bool Serialize(unsigned char *sig, int *size); void static secp256k1_ecdsa_sig_free(secp256k1_ecdsa_sig_t *r);
bool RecomputeR(secp256k1_num_t &r2, const secp256k1_gej_t &pubkey, const secp256k1_num_t &message) const;
bool Verify(const secp256k1_gej_t &pubkey, const secp256k1_num_t &message) const; int static secp256k1_ecdsa_pubkey_parse(secp256k1_gej_t *elem, const unsigned char *pub, int size);
bool Sign(const secp256k1_num_t &seckey, const secp256k1_num_t &message, const secp256k1_num_t &nonce); int static secp256k1_ecdsa_sig_parse(secp256k1_ecdsa_sig_t *r, const unsigned char *sig, int size);
void SetRS(const secp256k1_num_t &rin, const secp256k1_num_t &sin); int static secp256k1_ecdsa_sig_serialize(unsigned char *sig, int *size, const secp256k1_ecdsa_sig_t *a);
std::string ToString() const; int static secp256k1_ecdsa_sig_sign(secp256k1_ecdsa_sig_t *sig, const secp256k1_num_t *seckey, const secp256k1_num_t *message, const secp256k1_num_t *nonce);
}; void static secp256k1_ecdsa_sig_set_rs(secp256k1_ecdsa_sig_t *sig, const secp256k1_num_t *r, const secp256k1_num_t *s);
} }

23
src/secp256k1.cpp
View file

@ -4,47 +4,46 @@
#include "ecmult.cpp" #include "ecmult.cpp"
#include "ecdsa.cpp" #include "ecdsa.cpp"
extern "C" {
namespace secp256k1 { void secp256k1_start(void) {
extern "C" void secp256k1_start(void) {
secp256k1_num_start(); secp256k1_num_start();
secp256k1_fe_start(); secp256k1_fe_start();
secp256k1_ge_start(); secp256k1_ge_start();
secp256k1_ecmult_start(); secp256k1_ecmult_start();
} }
extern "C" void secp256k1_stop(void) { void secp256k1_stop(void) {
secp256k1_ecmult_stop(); secp256k1_ecmult_stop();
secp256k1_ge_stop(); secp256k1_ge_stop();
secp256k1_fe_stop(); secp256k1_fe_stop();
secp256k1_num_stop(); secp256k1_num_stop();
} }
extern "C" int secp256k1_ecdsa_verify(const unsigned char *msg, int msglen, const unsigned char *sig, int siglen, const unsigned char *pubkey, int pubkeylen) { int secp256k1_ecdsa_verify(const unsigned char *msg, int msglen, const unsigned char *sig, int siglen, const unsigned char *pubkey, int pubkeylen) {
int ret = -3; int ret = -3;
secp256k1_num_t m; secp256k1_num_t m;
secp256k1_num_init(&m); secp256k1_num_init(&m);
Signature s; secp256k1_ecdsa_sig_t s;
secp256k1_ecdsa_sig_init(&s);
secp256k1_gej_t q; secp256k1_gej_t q;
secp256k1_num_set_bin(&m, msg, msglen); secp256k1_num_set_bin(&m, msg, msglen);
if (!ParsePubKey(q, pubkey, pubkeylen)) {
if (!secp256k1_ecdsa_pubkey_parse(&q, pubkey, pubkeylen)) {
ret = -1; ret = -1;
goto end; goto end;
} }
if (!s.Parse(sig, siglen)) { if (!secp256k1_ecdsa_sig_parse(&s, sig, siglen)) {
fprintf(stderr, "Can't parse signature: ");
for (int i=0; i<siglen; i++) fprintf(stderr,"%02x", sig[i]);
fprintf(stderr, "\n");
ret = -2; ret = -2;
goto end; goto end;
} }
if (!s.Verify(q, m)) { if (!secp256k1_ecdsa_sig_verify(&s, &q, &m)) {
ret = 0; ret = 0;
goto end; goto end;
} }
ret = 1; ret = 1;
end: end:
secp256k1_ecdsa_sig_free(&s);
secp256k1_num_free(&m); secp256k1_num_free(&m);
return ret; return ret;
} }

12
src/tests.cpp
View file

@ -9,8 +9,6 @@
// #define COUNT 2 // #define COUNT 2
#define COUNT 100 #define COUNT 100
using namespace secp256k1;
void test_run_ecmult_chain() { void test_run_ecmult_chain() {
// random starting point A (on the curve) // random starting point A (on the curve)
secp256k1_fe_t ax; secp256k1_fe_set_hex(&ax, "8b30bbe9ae2a990696b22f670709dff3727fd8bc04d3362c6c7bf458e2846004", 64); secp256k1_fe_t ax; secp256k1_fe_set_hex(&ax, "8b30bbe9ae2a990696b22f670709dff3727fd8bc04d3362c6c7bf458e2846004", 64);
@ -159,13 +157,15 @@ void test_ecdsa_sign_verify() {
secp256k1_num_set_rand(&key, &c.order); secp256k1_num_set_rand(&key, &c.order);
secp256k1_num_init(&nonce); secp256k1_num_init(&nonce);
secp256k1_gej_t pub; secp256k1_ecmult_gen(&pub, &key); secp256k1_gej_t pub; secp256k1_ecmult_gen(&pub, &key);
Signature sig; secp256k1_ecdsa_sig_t sig;
secp256k1_ecdsa_sig_init(&sig);
do { do {
secp256k1_num_set_rand(&nonce, &c.order); secp256k1_num_set_rand(&nonce, &c.order);
} while(!sig.Sign(key, msg, nonce)); } while(!secp256k1_ecdsa_sig_sign(&sig, &key, &msg, &nonce));
assert(sig.Verify(pub, msg)); assert(secp256k1_ecdsa_sig_verify(&sig, &pub, &msg));
secp256k1_num_inc(&msg); secp256k1_num_inc(&msg);
assert(!sig.Verify(pub, msg)); assert(!secp256k1_ecdsa_sig_verify(&sig, &pub, &msg));
secp256k1_ecdsa_sig_free(&sig);
secp256k1_num_free(&msg); secp256k1_num_free(&msg);
secp256k1_num_free(&key); secp256k1_num_free(&key);
secp256k1_num_free(&nonce); secp256k1_num_free(&nonce);