blob: 1a7a7aaa0b7c9747bc094810f6edd8ceb394e7a4 [file] [log] [blame]
/******************************************************************************
*
* Copyright 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#include "security/ecdh_keys.h"
/**********************************************************************************************************************
TODO: We should have random number management in separate file, and we
should honour all the random number requirements from the spec!!
**********************************************************************************************************************/
#include <string.h>
#include <cstdlib>
#include <ctime>
#include "security/ecc/p_256_ecc_pp.h"
namespace {
static bool srand_initiated = false;
template <size_t SIZE>
static std::array<uint8_t, SIZE> GenerateRandom() {
if (!srand_initiated) {
srand_initiated = true;
// TODO: We need a proper random number generator here.
// use current time as seed for random generator
std::srand(std::time(nullptr));
}
std::array<uint8_t, SIZE> r;
for (size_t i = 0; i < SIZE; i++) r[i] = std::rand();
return r;
}
} // namespace
/*********************************************************************************************************************/
namespace bluetooth {
namespace security {
std::pair<std::array<uint8_t, 32>, EcdhPublicKey> GenerateECDHKeyPair() {
std::array<uint8_t, 32> private_key = GenerateRandom<32>();
std::array<uint8_t, 32> private_key_copy = private_key;
ecc::Point public_key;
ECC_PointMult(&public_key, &(ecc::curve_p256.G), (uint32_t*)private_key_copy.data());
EcdhPublicKey pk;
memcpy(pk.x.data(), public_key.x, 32);
memcpy(pk.y.data(), public_key.y, 32);
/* private_key, public key pair */
return std::make_pair<std::array<uint8_t, 32>, EcdhPublicKey>(std::move(private_key), std::move(pk));
}
bool ValidateECDHPoint(EcdhPublicKey pk) {
ecc::Point public_key;
memcpy(public_key.x, pk.x.data(), 32);
memcpy(public_key.y, pk.y.data(), 32);
memset(public_key.z, 0, 32);
return ECC_ValidatePoint(public_key);
}
std::array<uint8_t, 32> ComputeDHKey(std::array<uint8_t, 32> my_private_key, EcdhPublicKey remote_public_key) {
ecc::Point peer_publ_key, new_publ_key;
uint32_t private_key[8];
memcpy(private_key, my_private_key.data(), 32);
memcpy(peer_publ_key.x, remote_public_key.x.data(), 32);
memcpy(peer_publ_key.y, remote_public_key.y.data(), 32);
memset(peer_publ_key.z, 0, 32);
peer_publ_key.z[0] = 1;
ECC_PointMult(&new_publ_key, &peer_publ_key, (uint32_t*)private_key);
std::array<uint8_t, 32> dhkey;
memcpy(dhkey.data(), new_publ_key.x, 32);
return dhkey;
}
} // namespace security
} // namespace bluetooth