diff options
Diffstat (limited to 'src/secp256k1/src/tests_exhaustive.c')
| -rw-r--r-- | src/secp256k1/src/tests_exhaustive.c | 143 |
1 files changed, 142 insertions, 1 deletions
diff --git a/src/secp256k1/src/tests_exhaustive.c b/src/secp256k1/src/tests_exhaustive.c index bda6ee475c..b040bb0733 100644 --- a/src/secp256k1/src/tests_exhaustive.c +++ b/src/secp256k1/src/tests_exhaustive.c @@ -26,6 +26,11 @@ #include "secp256k1.c" #include "testrand_impl.h" +#ifdef ENABLE_MODULE_RECOVERY +#include "src/modules/recovery/main_impl.h" +#include "include/secp256k1_recovery.h" +#endif + /** stolen from tests.c */ void ge_equals_ge(const secp256k1_ge *a, const secp256k1_ge *b) { CHECK(a->infinity == b->infinity); @@ -77,7 +82,7 @@ int secp256k1_nonce_function_smallint(unsigned char *nonce32, const unsigned cha * function with an increased `attempt`. So if attempt > 0 this means we * need to change the nonce to avoid an infinite loop. */ if (attempt > 0) { - (*idata)++; + *idata = (*idata + 1) % EXHAUSTIVE_TEST_ORDER; } secp256k1_scalar_set_int(&s, *idata); secp256k1_scalar_get_b32(nonce32, &s); @@ -244,6 +249,7 @@ void test_exhaustive_sign(const secp256k1_context *ctx, const secp256k1_ge *grou for (i = 1; i < order; i++) { /* message */ for (j = 1; j < order; j++) { /* key */ for (k = 1; k < order; k++) { /* nonce */ + const int starting_k = k; secp256k1_ecdsa_signature sig; secp256k1_scalar sk, msg, r, s, expected_r; unsigned char sk32[32], msg32[32]; @@ -262,6 +268,11 @@ void test_exhaustive_sign(const secp256k1_context *ctx, const secp256k1_ge *grou CHECK(r == expected_r); CHECK((k * s) % order == (i + r * j) % order || (k * (EXHAUSTIVE_TEST_ORDER - s)) % order == (i + r * j) % order); + + /* Overflow means we've tried every possible nonce */ + if (k < starting_k) { + break; + } } } } @@ -276,6 +287,130 @@ void test_exhaustive_sign(const secp256k1_context *ctx, const secp256k1_ge *grou */ } +#ifdef ENABLE_MODULE_RECOVERY +void test_exhaustive_recovery_sign(const secp256k1_context *ctx, const secp256k1_ge *group, int order) { + int i, j, k; + + /* Loop */ + for (i = 1; i < order; i++) { /* message */ + for (j = 1; j < order; j++) { /* key */ + for (k = 1; k < order; k++) { /* nonce */ + const int starting_k = k; + secp256k1_fe r_dot_y_normalized; + secp256k1_ecdsa_recoverable_signature rsig; + secp256k1_ecdsa_signature sig; + secp256k1_scalar sk, msg, r, s, expected_r; + unsigned char sk32[32], msg32[32]; + int expected_recid; + int recid; + secp256k1_scalar_set_int(&msg, i); + secp256k1_scalar_set_int(&sk, j); + secp256k1_scalar_get_b32(sk32, &sk); + secp256k1_scalar_get_b32(msg32, &msg); + + secp256k1_ecdsa_sign_recoverable(ctx, &rsig, msg32, sk32, secp256k1_nonce_function_smallint, &k); + + /* Check directly */ + secp256k1_ecdsa_recoverable_signature_load(ctx, &r, &s, &recid, &rsig); + r_from_k(&expected_r, group, k); + CHECK(r == expected_r); + CHECK((k * s) % order == (i + r * j) % order || + (k * (EXHAUSTIVE_TEST_ORDER - s)) % order == (i + r * j) % order); + /* In computing the recid, there is an overflow condition that is disabled in + * scalar_low_impl.h `secp256k1_scalar_set_b32` because almost every r.y value + * will exceed the group order, and our signing code always holds out for r + * values that don't overflow, so with a proper overflow check the tests would + * loop indefinitely. */ + r_dot_y_normalized = group[k].y; + secp256k1_fe_normalize(&r_dot_y_normalized); + /* Also the recovery id is flipped depending if we hit the low-s branch */ + if ((k * s) % order == (i + r * j) % order) { + expected_recid = secp256k1_fe_is_odd(&r_dot_y_normalized) ? 1 : 0; + } else { + expected_recid = secp256k1_fe_is_odd(&r_dot_y_normalized) ? 0 : 1; + } + CHECK(recid == expected_recid); + + /* Convert to a standard sig then check */ + secp256k1_ecdsa_recoverable_signature_convert(ctx, &sig, &rsig); + secp256k1_ecdsa_signature_load(ctx, &r, &s, &sig); + /* Note that we compute expected_r *after* signing -- this is important + * because our nonce-computing function function might change k during + * signing. */ + r_from_k(&expected_r, group, k); + CHECK(r == expected_r); + CHECK((k * s) % order == (i + r * j) % order || + (k * (EXHAUSTIVE_TEST_ORDER - s)) % order == (i + r * j) % order); + + /* Overflow means we've tried every possible nonce */ + if (k < starting_k) { + break; + } + } + } + } +} + +void test_exhaustive_recovery_verify(const secp256k1_context *ctx, const secp256k1_ge *group, int order) { + /* This is essentially a copy of test_exhaustive_verify, with recovery added */ + int s, r, msg, key; + for (s = 1; s < order; s++) { + for (r = 1; r < order; r++) { + for (msg = 1; msg < order; msg++) { + for (key = 1; key < order; key++) { + secp256k1_ge nonconst_ge; + secp256k1_ecdsa_recoverable_signature rsig; + secp256k1_ecdsa_signature sig; + secp256k1_pubkey pk; + secp256k1_scalar sk_s, msg_s, r_s, s_s; + secp256k1_scalar s_times_k_s, msg_plus_r_times_sk_s; + int recid = 0; + int k, should_verify; + unsigned char msg32[32]; + + secp256k1_scalar_set_int(&s_s, s); + secp256k1_scalar_set_int(&r_s, r); + secp256k1_scalar_set_int(&msg_s, msg); + secp256k1_scalar_set_int(&sk_s, key); + secp256k1_scalar_get_b32(msg32, &msg_s); + + /* Verify by hand */ + /* Run through every k value that gives us this r and check that *one* works. + * Note there could be none, there could be multiple, ECDSA is weird. */ + should_verify = 0; + for (k = 0; k < order; k++) { + secp256k1_scalar check_x_s; + r_from_k(&check_x_s, group, k); + if (r_s == check_x_s) { + secp256k1_scalar_set_int(&s_times_k_s, k); + secp256k1_scalar_mul(&s_times_k_s, &s_times_k_s, &s_s); + secp256k1_scalar_mul(&msg_plus_r_times_sk_s, &r_s, &sk_s); + secp256k1_scalar_add(&msg_plus_r_times_sk_s, &msg_plus_r_times_sk_s, &msg_s); + should_verify |= secp256k1_scalar_eq(&s_times_k_s, &msg_plus_r_times_sk_s); + } + } + /* nb we have a "high s" rule */ + should_verify &= !secp256k1_scalar_is_high(&s_s); + + /* We would like to try recovering the pubkey and checking that it matches, + * but pubkey recovery is impossible in the exhaustive tests (the reason + * being that there are 12 nonzero r values, 12 nonzero points, and no + * overlap between the sets, so there are no valid signatures). */ + + /* Verify by converting to a standard signature and calling verify */ + secp256k1_ecdsa_recoverable_signature_save(&rsig, &r_s, &s_s, recid); + secp256k1_ecdsa_recoverable_signature_convert(ctx, &sig, &rsig); + memcpy(&nonconst_ge, &group[sk_s], sizeof(nonconst_ge)); + secp256k1_pubkey_save(&pk, &nonconst_ge); + CHECK(should_verify == + secp256k1_ecdsa_verify(ctx, &sig, msg32, &pk)); + } + } + } + } +} +#endif + int main(void) { int i; secp256k1_gej groupj[EXHAUSTIVE_TEST_ORDER]; @@ -324,6 +459,12 @@ int main(void) { test_exhaustive_sign(ctx, group, EXHAUSTIVE_TEST_ORDER); test_exhaustive_verify(ctx, group, EXHAUSTIVE_TEST_ORDER); +#ifdef ENABLE_MODULE_RECOVERY + test_exhaustive_recovery_sign(ctx, group, EXHAUSTIVE_TEST_ORDER); + test_exhaustive_recovery_verify(ctx, group, EXHAUSTIVE_TEST_ORDER); +#endif + + secp256k1_context_destroy(ctx); return 0; } |