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[ECDH API change] Allow pass arbitrary data to hash function

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This commit is contained in:
Kirill Fomichev
2018-05-17 00:12:46 +03:00
parent b00be65056
commit c8fbc3c397
5 changed files with 27 additions and 19 deletions
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7
src/modules/ecdh/main_impl.h
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@@ -10,9 +10,10 @@
#include "include/secp256k1_ecdh.h"
#include "ecmult_const_impl.h"
static int ecdh_hash_function_sha256(unsigned char *output, const unsigned char *x, const unsigned char *y) {
static int ecdh_hash_function_sha256(unsigned char *output, const unsigned char *x, const unsigned char *y, void *data) {
unsigned char version = (y[31] & 0x01) | 0x02;
secp256k1_sha256 sha;
(void)data;
secp256k1_sha256_initialize(&sha);
secp256k1_sha256_write(&sha, &version, 1);
@@ -25,7 +26,7 @@ static int ecdh_hash_function_sha256(unsigned char *output, const unsigned char
const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_sha256 = ecdh_hash_function_sha256;
const secp256k1_ecdh_hash_function secp256k1_ecdh_hash_function_default = ecdh_hash_function_sha256;
int secp256k1_ecdh(const secp256k1_context* ctx, unsigned char *output, const secp256k1_pubkey *point, const unsigned char *scalar, secp256k1_ecdh_hash_function hashfp) {
int secp256k1_ecdh(const secp256k1_context* ctx, unsigned char *output, const secp256k1_pubkey *point, const unsigned char *scalar, secp256k1_ecdh_hash_function hashfp, void *data) {
int ret = 0;
int overflow = 0;
secp256k1_gej res;
@@ -56,7 +57,7 @@ int secp256k1_ecdh(const secp256k1_context* ctx, unsigned char *output, const se
secp256k1_fe_get_b32(x, &pt.x);
secp256k1_fe_get_b32(y, &pt.y);
ret = hashfp(output, x, y);
ret = hashfp(output, x, y, data);
}
secp256k1_scalar_clear(&s);

28
src/modules/ecdh/tests_impl.h
View File

@@ -7,14 +7,16 @@
#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) {
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) {
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);
@@ -36,15 +38,15 @@ void test_ecdh_api(void) {
CHECK(secp256k1_ec_pubkey_create(tctx, &point, s_one) == 1);
/* Check all NULLs are detected */
CHECK(secp256k1_ecdh(tctx, res, &point, s_one, NULL) == 1);
CHECK(secp256k1_ecdh(tctx, res, &point, s_one, NULL, NULL) == 1);
CHECK(ecount == 0);
CHECK(secp256k1_ecdh(tctx, NULL, &point, s_one, NULL) == 0);
CHECK(secp256k1_ecdh(tctx, NULL, &point, s_one, NULL, NULL) == 0);
CHECK(ecount == 1);
CHECK(secp256k1_ecdh(tctx, res, NULL, s_one, NULL) == 0);
CHECK(secp256k1_ecdh(tctx, res, NULL, s_one, NULL, NULL) == 0);
CHECK(ecount == 2);
CHECK(secp256k1_ecdh(tctx, res, &point, NULL, NULL) == 0);
CHECK(secp256k1_ecdh(tctx, res, &point, NULL, NULL, NULL) == 0);
CHECK(ecount == 3);
CHECK(secp256k1_ecdh(tctx, res, &point, s_one, NULL) == 1);
CHECK(secp256k1_ecdh(tctx, res, &point, s_one, NULL, NULL) == 1);
CHECK(ecount == 3);
/* Cleanup */
@@ -74,14 +76,14 @@ void test_ecdh_generator_basepoint(void) {
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) == 1);
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) == 1);
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);
@@ -111,14 +113,14 @@ void test_bad_scalar(void) {
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) == 0);
CHECK(secp256k1_ecdh(ctx, output, &point, s_overflow, NULL) == 0);
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) == 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) == 0);
CHECK(secp256k1_ecdh(ctx, output, &point, s_overflow, ecdh_hash_function_test_fail, NULL) == 0);
}
void run_ecdh_tests(void) {