Add tests for bad scalar inputs in ellswift XDH

This commit is contained in:
gzJx0DuTRHytnHe7P5RmMbPf3wKy2BztweVGXTf
2026-02-13 00:19:54 +01:00
committed by SHAKE256
parent 307b49f1b9
commit b99a94c382

View File

@@ -460,6 +460,33 @@ void ellswift_hash_init_tests(void) {
test_sha256_tag_midstate(&sha_optimized, bip324_tag, sizeof(bip324_tag));
}
void ellswift_xdh_bad_scalar_tests(void) {
unsigned char s_zero[32] = { 0 };
unsigned char s_overflow_minus1[32] = { 0 };
unsigned char s_overflow_plus1[32] = { 0 };
unsigned char s_good[32] = { 0 };
unsigned char ell_a64[64], ell_b64[64];
unsigned char output[32];
secp256k1_scalar rand_scalar;
testutil_random_scalar_order(&rand_scalar);
secp256k1_scalar_get_b32(s_good, &rand_scalar);
CHECK(secp256k1_ellswift_create(CTX, ell_a64, s_good, NULL) == 1);
testrand256_test(ell_b64);
testrand256_test(ell_b64 + 32);
memcpy(s_overflow_minus1, secp256k1_group_order_bytes, 32);
s_overflow_minus1[31] -= 1;
memcpy(s_overflow_plus1, secp256k1_group_order_bytes, 32);
s_overflow_plus1[31] += 1;
CHECK(secp256k1_ellswift_xdh(CTX, output, ell_a64, ell_b64, s_zero, 0, &ellswift_xdh_hash_x32, NULL) == 0);
CHECK(secp256k1_ellswift_xdh(CTX, output, ell_a64, ell_b64, secp256k1_group_order_bytes, 0, &ellswift_xdh_hash_x32, NULL) == 0);
CHECK(secp256k1_ellswift_xdh(CTX, output, ell_a64, ell_b64, s_overflow_plus1, 0, &ellswift_xdh_hash_x32, NULL) == 0);
CHECK(secp256k1_ellswift_xdh(CTX, output, ell_a64, ell_b64, s_overflow_minus1, 0, &ellswift_xdh_hash_x32, NULL) == 1);
}
/* --- Test registry --- */
static const struct tf_test_entry tests_ellswift[] = {
CASE1(ellswift_encoding_test_vectors_tests),
@@ -470,6 +497,7 @@ static const struct tf_test_entry tests_ellswift[] = {
CASE1(ellswift_compute_shared_secret_tests),
CASE1(ellswift_xdh_correctness_tests),
CASE1(ellswift_hash_init_tests),
CASE1(ellswift_xdh_bad_scalar_tests),
};
#endif