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Switch all EC/ECDSA logic from num to scalar

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This commit is contained in:
Pieter Wuille
2014-11-26 17:26:39 +01:00
parent 6794be6080
commit f24041d6aa
15 changed files with 285 additions and 192 deletions
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129
src/tests.c
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@@ -100,6 +100,18 @@ void random_scalar_order_test(secp256k1_scalar_t *num) {
} while(1);
}
void random_scalar_order(secp256k1_scalar_t *num) {
do {
unsigned char b32[32];
secp256k1_rand256(b32);
int overflow = 0;
secp256k1_scalar_set_b32(num, b32, &overflow);
if (overflow || secp256k1_scalar_is_zero(num))
continue;
break;
} while(1);
}
void random_num_order(secp256k1_num_t *num) {
do {
unsigned char b32[32];
@@ -240,14 +252,6 @@ void run_num_smalltests(void) {
/***** SCALAR TESTS *****/
int secp256k1_scalar_eq(const secp256k1_scalar_t *s1, const secp256k1_scalar_t *s2) {
secp256k1_scalar_t t;
secp256k1_scalar_negate(&t, s2);
secp256k1_scalar_add(&t, &t, s1);
int ret = secp256k1_scalar_is_zero(&t);
return ret;
}
void scalar_test(void) {
unsigned char c[32];
@@ -746,35 +750,47 @@ void run_ecmult_chain(void) {
secp256k1_fe_t ay; VERIFY_CHECK(secp256k1_fe_set_hex(&ay, "a357ae915c4a65281309edf20504740f0eb3343990216b4f81063cb65f2f7e0f", 64));
secp256k1_gej_t a; secp256k1_gej_set_xy(&a, &ax, &ay);
/* two random initial factors xn and gn */
secp256k1_num_t xn;
secp256k1_num_set_hex(&xn, "84cc5452f7fde1edb4d38a8ce9b1b84ccef31f146e569be9705d357a42985407", 64);
secp256k1_num_t gn;
secp256k1_num_set_hex(&gn, "a1e58d22553dcd42b23980625d4c57a96e9323d42b3152e5ca2c3990edc7c9de", 64);
static const unsigned char xni[32] = {
0x84, 0xcc, 0x54, 0x52, 0xf7, 0xfd, 0xe1, 0xed,
0xb4, 0xd3, 0x8a, 0x8c, 0xe9, 0xb1, 0xb8, 0x4c,
0xce, 0xf3, 0x1f, 0x14, 0x6e, 0x56, 0x9b, 0xe9,
0x70, 0x5d, 0x35, 0x7a, 0x42, 0x98, 0x54, 0x07
};
secp256k1_scalar_t xn;
secp256k1_scalar_set_b32(&xn, xni, NULL);
static const unsigned char gni[32] = {
0xa1, 0xe5, 0x8d, 0x22, 0x55, 0x3d, 0xcd, 0x42,
0xb2, 0x39, 0x80, 0x62, 0x5d, 0x4c, 0x57, 0xa9,
0x6e, 0x93, 0x23, 0xd4, 0x2b, 0x31, 0x52, 0xe5,
0xca, 0x2c, 0x39, 0x90, 0xed, 0xc7, 0xc9, 0xde
};
secp256k1_scalar_t gn;
secp256k1_scalar_set_b32(&gn, gni, NULL);
/* two small multipliers to be applied to xn and gn in every iteration: */
secp256k1_num_t xf;
secp256k1_num_set_hex(&xf, "1337", 4);
secp256k1_num_t gf;
secp256k1_num_set_hex(&gf, "7113", 4);
static const unsigned char xfi[32] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0x13,0x37};
secp256k1_scalar_t xf;
secp256k1_scalar_set_b32(&xf, xfi, NULL);
static const unsigned char gfi[32] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0x71,0x13};
secp256k1_scalar_t gf;
secp256k1_scalar_set_b32(&gf, gfi, NULL);
/* accumulators with the resulting coefficients to A and G */
secp256k1_num_t ae;
secp256k1_num_set_int(&ae, 1);
secp256k1_num_t ge;
secp256k1_num_set_int(&ge, 0);
secp256k1_scalar_t ae;
secp256k1_scalar_set_int(&ae, 1);
secp256k1_scalar_t ge;
secp256k1_scalar_set_int(&ge, 0);
/* the point being computed */
secp256k1_gej_t x = a;
const secp256k1_num_t *order = &secp256k1_ge_consts->order;
for (int i=0; i<200*count; i++) {
/* in each iteration, compute X = xn*X + gn*G; */
secp256k1_ecmult(&x, &x, &xn, &gn);
/* also compute ae and ge: the actual accumulated factors for A and G */
/* if X was (ae*A+ge*G), xn*X + gn*G results in (xn*ae*A + (xn*ge+gn)*G) */
secp256k1_num_mod_mul(&ae, &ae, &xn, order);
secp256k1_num_mod_mul(&ge, &ge, &xn, order);
secp256k1_num_add(&ge, &ge, &gn);
secp256k1_num_mod(&ge, order);
secp256k1_scalar_mul(&ae, &ae, &xn);
secp256k1_scalar_mul(&ge, &ge, &xn);
secp256k1_scalar_add(&ge, &ge, &gn);
/* modify xn and gn */
secp256k1_num_mod_mul(&xn, &xn, &xf, order);
secp256k1_num_mod_mul(&gn, &gn, &gf, order);
secp256k1_scalar_mul(&xn, &xn, &xf);
secp256k1_scalar_mul(&gn, &gn, &gf);
/* verify */
if (i == 19999) {
@@ -795,10 +811,10 @@ void run_ecmult_chain(void) {
void test_point_times_order(const secp256k1_gej_t *point) {
/* X * (point + G) + (order-X) * (pointer + G) = 0 */
secp256k1_num_t x;
random_num_order_test(&x);
secp256k1_num_t nx;
secp256k1_num_sub(&nx, &secp256k1_ge_consts->order, &x);
secp256k1_scalar_t x;
random_scalar_order_test(&x);
secp256k1_scalar_t nx;
secp256k1_scalar_negate(&nx, &x);
secp256k1_gej_t res1, res2;
secp256k1_ecmult(&res1, point, &x, &x); /* calc res1 = x * point + x * G; */
secp256k1_ecmult(&res2, point, &nx, &nx); /* calc res2 = (order - x) * point + (order - x) * G; */
@@ -824,16 +840,16 @@ void run_point_times_order(void) {
CHECK(strcmp(c, "7603CB59B0EF6C63FE6084792A0C378CDB3233A80F8A9A09A877DEAD31B38C45") == 0);
}
void test_wnaf(const secp256k1_num_t *number, int w) {
secp256k1_num_t x, two, t;
secp256k1_num_set_int(&x, 0);
secp256k1_num_set_int(&two, 2);
void test_wnaf(const secp256k1_scalar_t *number, int w) {
secp256k1_scalar_t x, two, t;
secp256k1_scalar_set_int(&x, 0);
secp256k1_scalar_set_int(&two, 2);
int wnaf[256];
int bits = secp256k1_ecmult_wnaf(wnaf, number, w);
CHECK(bits <= 256);
int zeroes = -1;
for (int i=bits-1; i>=0; i--) {
secp256k1_num_mul(&x, &x, &two);
secp256k1_scalar_mul(&x, &x, &two);
int v = wnaf[i];
if (v) {
CHECK(zeroes == -1 || zeroes >= w-1); /* check that distance between non-zero elements is at least w-1 */
@@ -845,21 +861,23 @@ void test_wnaf(const secp256k1_num_t *number, int w) {
CHECK(zeroes != -1); /* check that no unnecessary zero padding exists */
zeroes++;
}
secp256k1_num_set_int(&t, v);
secp256k1_num_add(&x, &x, &t);
if (v >= 0) {
secp256k1_scalar_set_int(&t, v);
} else {
secp256k1_scalar_set_int(&t, -v);
secp256k1_scalar_negate(&t, &t);
}
secp256k1_scalar_add(&x, &x, &t);
}
secp256k1_num_t xcopy = x, ncopy = *number;
secp256k1_num_mod(&xcopy, &secp256k1_ge_consts->order);
secp256k1_num_mod(&ncopy, &secp256k1_ge_consts->order);
CHECK(secp256k1_num_eq(&xcopy, &ncopy)); /* check that wnaf represents number */
CHECK(secp256k1_scalar_eq(&x, number)); /* check that wnaf represents number */
}
void run_wnaf(void) {
secp256k1_num_t n;
secp256k1_scalar_t n;
for (int i=0; i<count; i++) {
random_num_order(&n);
random_scalar_order(&n);
if (i % 1)
secp256k1_num_negate(&n);
secp256k1_scalar_negate(&n, &n);
test_wnaf(&n, 4+(i%10));
}
}
@@ -879,11 +897,11 @@ void test_ecdsa_sign_verify(void) {
secp256k1_ge_t pub; secp256k1_ge_set_gej(&pub, &pubj);
secp256k1_ecdsa_sig_t sig;
random_sign(&sig, &key, &msg, NULL);
secp256k1_num_t msg_num;
secp256k1_scalar_get_num(&msg_num, &msg);
CHECK(secp256k1_ecdsa_sig_verify(&sig, &pub, &msg_num));
secp256k1_num_inc(&msg_num);
CHECK(!secp256k1_ecdsa_sig_verify(&sig, &pub, &msg_num));
CHECK(secp256k1_ecdsa_sig_verify(&sig, &pub, &msg));
secp256k1_scalar_t one;
secp256k1_scalar_set_int(&one, 1);
secp256k1_scalar_add(&msg, &msg, &one);
CHECK(!secp256k1_ecdsa_sig_verify(&sig, &pub, &msg));
}
void run_ecdsa_sign_verify(void) {
@@ -1071,11 +1089,12 @@ void test_ecdsa_openssl(void) {
CHECK(ECDSA_sign(0, message, sizeof(message), signature, &sigsize, ec_key));
secp256k1_ecdsa_sig_t sig;
CHECK(secp256k1_ecdsa_sig_parse(&sig, signature, sigsize));
secp256k1_num_t msg_num;
secp256k1_scalar_get_num(&msg_num, &msg);
CHECK(secp256k1_ecdsa_sig_verify(&sig, &q, &msg_num));
secp256k1_num_inc(&sig.r);
CHECK(!secp256k1_ecdsa_sig_verify(&sig, &q, &msg_num));
CHECK(secp256k1_ecdsa_sig_verify(&sig, &q, &msg));
secp256k1_scalar_t one;
secp256k1_scalar_set_int(&one, 1);
secp256k1_scalar_t msg2;
secp256k1_scalar_add(&msg2, &msg, &one);
CHECK(!secp256k1_ecdsa_sig_verify(&sig, &q, &msg2));
random_sign(&sig, &key, &msg, NULL);
int secp_sigsize = 80;