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/**********************************************************************
* Copyright (c) 2015 Andrew Poelstra *
* Distributed under the MIT software license, see the accompanying *
* file COPYING or http://www.opensource.org/licenses/mit-license.php.*
**********************************************************************/
#ifndef SECP256K1_MODULE_ECDH_TESTS_H
#define SECP256K1_MODULE_ECDH_TESTS_H
int ecdh_hash_function_test_fail(unsigned char *output, const unsigned char *x, const unsigned char *y, void *data) {
(void)output;
(void)x;
(void)y;
(void)data;
return 0;
}
int ecdh_hash_function_custom(unsigned char *output, const unsigned char *x, const unsigned char *y, void *data) {
(void)data;
/* Save x and y as uncompressed public key */
output[0] = 0x04;
memcpy(output + 1, x, 32);
memcpy(output + 33, y, 32);
return 1;
}
void test_ecdh_api(void) {
/* Setup context that just counts errors */
secp256k1_context *tctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN);
secp256k1_pubkey point;
unsigned char res[32];
unsigned char s_one[32] = { 0 };
int32_t ecount = 0;
s_one[31] = 1;
secp256k1_context_set_error_callback(tctx, counting_illegal_callback_fn, &ecount);
secp256k1_context_set_illegal_callback(tctx, counting_illegal_callback_fn, &ecount);
CHECK(secp256k1_ec_pubkey_create(tctx, &point, s_one) == 1);
/* Check all NULLs are detected */
CHECK(secp256k1_ecdh(tctx, res, &point, s_one, NULL, NULL) == 1);
CHECK(ecount == 0);
CHECK(secp256k1_ecdh(tctx, NULL, &point, s_one, NULL, NULL) == 0);
CHECK(ecount == 1);
CHECK(secp256k1_ecdh(tctx, res, NULL, s_one, NULL, NULL) == 0);
CHECK(ecount == 2);
CHECK(secp256k1_ecdh(tctx, res, &point, NULL, NULL, NULL) == 0);
CHECK(ecount == 3);
CHECK(secp256k1_ecdh(tctx, res, &point, s_one, NULL, NULL) == 1);
CHECK(ecount == 3);
/* Cleanup */
secp256k1_context_destroy(tctx);
}
void test_ecdh_generator_basepoint(void) {
unsigned char s_one[32] = { 0 };
secp256k1_pubkey point[2];
int i;
s_one[31] = 1;
/* Check against pubkey creation when the basepoint is the generator */
for (i = 0; i < 100; ++i) {
secp256k1_sha256 sha;
unsigned char s_b32[32];
unsigned char output_ecdh[65];
unsigned char output_ser[32];
unsigned char point_ser[65];
size_t point_ser_len = sizeof(point_ser);
secp256k1_scalar s;
random_scalar_order(&s);
secp256k1_scalar_get_b32(s_b32, &s);
CHECK(secp256k1_ec_pubkey_create(ctx, &point[0], s_one) == 1);
CHECK(secp256k1_ec_pubkey_create(ctx, &point[1], s_b32) == 1);
/* compute using ECDH function with custom hash function */
CHECK(secp256k1_ecdh(ctx, output_ecdh, &point[0], s_b32, ecdh_hash_function_custom, NULL) == 1);
/* compute "explicitly" */
CHECK(secp256k1_ec_pubkey_serialize(ctx, point_ser, &point_ser_len, &point[1], SECP256K1_EC_UNCOMPRESSED) == 1);
/* compare */
CHECK(memcmp(output_ecdh, point_ser, 65) == 0);
/* compute using ECDH function with default hash function */
CHECK(secp256k1_ecdh(ctx, output_ecdh, &point[0], s_b32, NULL, NULL) == 1);
/* compute "explicitly" */
CHECK(secp256k1_ec_pubkey_serialize(ctx, point_ser, &point_ser_len, &point[1], SECP256K1_EC_COMPRESSED) == 1);
secp256k1_sha256_initialize(&sha);
secp256k1_sha256_write(&sha, point_ser, point_ser_len);
secp256k1_sha256_finalize(&sha, output_ser);
/* compare */
CHECK(memcmp(output_ecdh, output_ser, 32) == 0);
}
}
void test_bad_scalar(void) {
unsigned char s_zero[32] = { 0 };
unsigned char s_overflow[32] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe,
0xba, 0xae, 0xdc, 0xe6, 0xaf, 0x48, 0xa0, 0x3b,
0xbf, 0xd2, 0x5e, 0x8c, 0xd0, 0x36, 0x41, 0x41
};
unsigned char s_rand[32] = { 0 };
unsigned char output[32];
secp256k1_scalar rand;
secp256k1_pubkey point;
/* Create random point */
random_scalar_order(&rand);
secp256k1_scalar_get_b32(s_rand, &rand);
CHECK(secp256k1_ec_pubkey_create(ctx, &point, s_rand) == 1);
/* Try to multiply it by bad values */
CHECK(secp256k1_ecdh(ctx, output, &point, s_zero, NULL, NULL) == 0);
CHECK(secp256k1_ecdh(ctx, output, &point, s_overflow, NULL, NULL) == 0);
/* ...and a good one */
s_overflow[31] -= 1;
CHECK(secp256k1_ecdh(ctx, output, &point, s_overflow, NULL, NULL) == 1);
/* Hash function failure results in ecdh failure */
CHECK(secp256k1_ecdh(ctx, output, &point, s_overflow, ecdh_hash_function_test_fail, NULL) == 0);
}
void run_ecdh_tests(void) {
test_ecdh_api();
test_ecdh_generator_basepoint();
test_bad_scalar();
}
#endif /* SECP256K1_MODULE_ECDH_TESTS_H */
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