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Diffstat (limited to 'src/modules/schnorrsig/tests_exhaustive_impl.h')
| -rw-r--r-- | src/modules/schnorrsig/tests_exhaustive_impl.h | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/modules/schnorrsig/tests_exhaustive_impl.h b/src/modules/schnorrsig/tests_exhaustive_impl.h new file mode 100644 index 0000000000..4bf0bc1680 --- /dev/null +++ b/src/modules/schnorrsig/tests_exhaustive_impl.h @@ -0,0 +1,206 @@ +/********************************************************************** + * Copyright (c) 2020 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or http://www.opensource.org/licenses/mit-license.php.* + **********************************************************************/ + +#ifndef _SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_ +#define _SECP256K1_MODULE_SCHNORRSIG_TESTS_EXHAUSTIVE_ + +#include "include/secp256k1_schnorrsig.h" +#include "src/modules/schnorrsig/main_impl.h" + +static const unsigned char invalid_pubkey_bytes[][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, 0, 0, 0 + }, + /* 2 */ + { + 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, 0, 2 + }, + /* order */ + { + 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, + ((EXHAUSTIVE_TEST_ORDER + 0UL) >> 24) & 0xFF, + ((EXHAUSTIVE_TEST_ORDER + 0UL) >> 16) & 0xFF, + ((EXHAUSTIVE_TEST_ORDER + 0UL) >> 8) & 0xFF, + (EXHAUSTIVE_TEST_ORDER + 0UL) & 0xFF + }, + /* order + 1 */ + { + 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, + ((EXHAUSTIVE_TEST_ORDER + 1UL) >> 24) & 0xFF, + ((EXHAUSTIVE_TEST_ORDER + 1UL) >> 16) & 0xFF, + ((EXHAUSTIVE_TEST_ORDER + 1UL) >> 8) & 0xFF, + (EXHAUSTIVE_TEST_ORDER + 1UL) & 0xFF + }, + /* field size */ + { + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFC, 0x2F + }, + /* field size + 1 (note that 1 is legal) */ + { + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFC, 0x30 + }, + /* 2^256 - 1 */ + { + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, + 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF + } +}; + +#define NUM_INVALID_KEYS (sizeof(invalid_pubkey_bytes) / sizeof(invalid_pubkey_bytes[0])) + +static int secp256k1_hardened_nonce_function_smallint(unsigned char *nonce32, const unsigned char *msg32, + const unsigned char *key32, const unsigned char *xonly_pk32, + const unsigned char *algo16, void* data) { + secp256k1_scalar s; + int *idata = data; + (void)msg32; + (void)key32; + (void)xonly_pk32; + (void)algo16; + secp256k1_scalar_set_int(&s, *idata); + secp256k1_scalar_get_b32(nonce32, &s); + return 1; +} + +static void test_exhaustive_schnorrsig_verify(const secp256k1_context *ctx, const secp256k1_xonly_pubkey* pubkeys, unsigned char (*xonly_pubkey_bytes)[32], const int* parities) { + int d; + uint64_t iter = 0; + /* Iterate over the possible public keys to verify against (through their corresponding DL d). */ + for (d = 1; d <= EXHAUSTIVE_TEST_ORDER / 2; ++d) { + int actual_d; + unsigned k; + unsigned char pk32[32]; + memcpy(pk32, xonly_pubkey_bytes[d - 1], 32); + actual_d = parities[d - 1] ? EXHAUSTIVE_TEST_ORDER - d : d; + /* Iterate over the possible valid first 32 bytes in the signature, through their corresponding DL k. + Values above EXHAUSTIVE_TEST_ORDER/2 refer to the entries in invalid_pubkey_bytes. */ + for (k = 1; k <= EXHAUSTIVE_TEST_ORDER / 2 + NUM_INVALID_KEYS; ++k) { + unsigned char sig64[64]; + int actual_k = -1; + int e_done[EXHAUSTIVE_TEST_ORDER] = {0}; + int e_count_done = 0; + if (skip_section(&iter)) continue; + if (k <= EXHAUSTIVE_TEST_ORDER / 2) { + memcpy(sig64, xonly_pubkey_bytes[k - 1], 32); + actual_k = parities[k - 1] ? EXHAUSTIVE_TEST_ORDER - k : k; + } else { + memcpy(sig64, invalid_pubkey_bytes[k - 1 - EXHAUSTIVE_TEST_ORDER / 2], 32); + } + /* Randomly generate messages until all challenges have been hit. */ + while (e_count_done < EXHAUSTIVE_TEST_ORDER) { + secp256k1_scalar e; + unsigned char msg32[32]; + secp256k1_testrand256(msg32); + secp256k1_schnorrsig_challenge(&e, sig64, msg32, pk32); + /* Only do work if we hit a challenge we haven't tried before. */ + if (!e_done[e]) { + /* Iterate over the possible valid last 32 bytes in the signature. + 0..order=that s value; order+1=random bytes */ + int count_valid = 0, s; + for (s = 0; s <= EXHAUSTIVE_TEST_ORDER + 1; ++s) { + int expect_valid, valid; + if (s <= EXHAUSTIVE_TEST_ORDER) { + secp256k1_scalar s_s; + secp256k1_scalar_set_int(&s_s, s); + secp256k1_scalar_get_b32(sig64 + 32, &s_s); + expect_valid = actual_k != -1 && s != EXHAUSTIVE_TEST_ORDER && + (s_s == (actual_k + actual_d * e) % EXHAUSTIVE_TEST_ORDER); + } else { + secp256k1_testrand256(sig64 + 32); + expect_valid = 0; + } + valid = secp256k1_schnorrsig_verify(ctx, sig64, msg32, &pubkeys[d - 1]); + CHECK(valid == expect_valid); + count_valid += valid; + } + /* Exactly one s value must verify, unless R is illegal. */ + CHECK(count_valid == (actual_k != -1)); + /* Don't retry other messages that result in the same challenge. */ + e_done[e] = 1; + ++e_count_done; + } + } + } + } +} + +static void test_exhaustive_schnorrsig_sign(const secp256k1_context *ctx, unsigned char (*xonly_pubkey_bytes)[32], const secp256k1_keypair* keypairs, const int* parities) { + int d, k; + uint64_t iter = 0; + /* Loop over keys. */ + for (d = 1; d < EXHAUSTIVE_TEST_ORDER; ++d) { + int actual_d = d; + if (parities[d - 1]) actual_d = EXHAUSTIVE_TEST_ORDER - d; + /* Loop over nonces. */ + for (k = 1; k < EXHAUSTIVE_TEST_ORDER; ++k) { + int e_done[EXHAUSTIVE_TEST_ORDER] = {0}; + int e_count_done = 0; + unsigned char msg32[32]; + unsigned char sig64[64]; + int actual_k = k; + if (skip_section(&iter)) continue; + if (parities[k - 1]) actual_k = EXHAUSTIVE_TEST_ORDER - k; + /* Generate random messages until all challenges have been tried. */ + while (e_count_done < EXHAUSTIVE_TEST_ORDER) { + secp256k1_scalar e; + secp256k1_testrand256(msg32); + secp256k1_schnorrsig_challenge(&e, xonly_pubkey_bytes[k - 1], msg32, xonly_pubkey_bytes[d - 1]); + /* Only do work if we hit a challenge we haven't tried before. */ + if (!e_done[e]) { + secp256k1_scalar expected_s = (actual_k + e * actual_d) % EXHAUSTIVE_TEST_ORDER; + unsigned char expected_s_bytes[32]; + secp256k1_scalar_get_b32(expected_s_bytes, &expected_s); + /* Invoke the real function to construct a signature. */ + CHECK(secp256k1_schnorrsig_sign(ctx, sig64, msg32, &keypairs[d - 1], secp256k1_hardened_nonce_function_smallint, &k)); + /* The first 32 bytes must match the xonly pubkey for the specified k. */ + CHECK(secp256k1_memcmp_var(sig64, xonly_pubkey_bytes[k - 1], 32) == 0); + /* The last 32 bytes must match the expected s value. */ + CHECK(secp256k1_memcmp_var(sig64 + 32, expected_s_bytes, 32) == 0); + /* Don't retry other messages that result in the same challenge. */ + e_done[e] = 1; + ++e_count_done; + } + } + } + } +} + +static void test_exhaustive_schnorrsig(const secp256k1_context *ctx) { + secp256k1_keypair keypair[EXHAUSTIVE_TEST_ORDER - 1]; + secp256k1_xonly_pubkey xonly_pubkey[EXHAUSTIVE_TEST_ORDER - 1]; + int parity[EXHAUSTIVE_TEST_ORDER - 1]; + unsigned char xonly_pubkey_bytes[EXHAUSTIVE_TEST_ORDER - 1][32]; + unsigned i; + + /* Verify that all invalid_pubkey_bytes are actually invalid. */ + for (i = 0; i < NUM_INVALID_KEYS; ++i) { + secp256k1_xonly_pubkey pk; + CHECK(!secp256k1_xonly_pubkey_parse(ctx, &pk, invalid_pubkey_bytes[i])); + } + + /* Construct keypairs and xonly-pubkeys for the entire group. */ + for (i = 1; i < EXHAUSTIVE_TEST_ORDER; ++i) { + secp256k1_scalar scalar_i; + unsigned char buf[32]; + secp256k1_scalar_set_int(&scalar_i, i); + secp256k1_scalar_get_b32(buf, &scalar_i); + CHECK(secp256k1_keypair_create(ctx, &keypair[i - 1], buf)); + CHECK(secp256k1_keypair_xonly_pub(ctx, &xonly_pubkey[i - 1], &parity[i - 1], &keypair[i - 1])); + CHECK(secp256k1_xonly_pubkey_serialize(ctx, xonly_pubkey_bytes[i - 1], &xonly_pubkey[i - 1])); + } + + test_exhaustive_schnorrsig_sign(ctx, xonly_pubkey_bytes, keypair, parity); + test_exhaustive_schnorrsig_verify(ctx, xonly_pubkey, xonly_pubkey_bytes, parity); +} + +#endif |