| // Copyright (c) 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "net/quic/crypto/curve25519_key_exchange.h" |
| |
| #include "base/logging.h" |
| #include "crypto/curve25519.h" |
| #include "net/quic/crypto/quic_random.h" |
| |
| using base::StringPiece; |
| using std::string; |
| |
| namespace net { |
| |
| Curve25519KeyExchange::Curve25519KeyExchange() { |
| } |
| |
| Curve25519KeyExchange::~Curve25519KeyExchange() { |
| } |
| |
| // static |
| Curve25519KeyExchange* Curve25519KeyExchange::New( |
| const StringPiece& private_key) { |
| Curve25519KeyExchange* ka; |
| // We don't want to #include the NaCl headers in the public header file, so |
| // we use literals for the sizes of private_key_ and public_key_. Here we |
| // assert that those values are equal to the values from the NaCl header. |
| COMPILE_ASSERT( |
| sizeof(ka->private_key_) == crypto::curve25519::kScalarBytes, |
| header_out_of_sync); |
| COMPILE_ASSERT( |
| sizeof(ka->public_key_) == crypto::curve25519::kBytes, |
| header_out_of_sync); |
| |
| if (private_key.size() != crypto::curve25519::kScalarBytes) { |
| return NULL; |
| } |
| |
| ka = new Curve25519KeyExchange(); |
| memcpy(ka->private_key_, private_key.data(), |
| crypto::curve25519::kScalarBytes); |
| crypto::curve25519::ScalarBaseMult(ka->private_key_, ka->public_key_); |
| return ka; |
| } |
| |
| // static |
| string Curve25519KeyExchange::NewPrivateKey(QuicRandom* rand) { |
| uint8 private_key[crypto::curve25519::kScalarBytes]; |
| rand->RandBytes(private_key, sizeof(private_key)); |
| |
| // This makes |private_key| a valid scalar, as specified on |
| // http://cr.yp.to/ecdh.html |
| private_key[0] &= 248; |
| private_key[31] &= 127; |
| private_key[31] |= 64; |
| return string(reinterpret_cast<char*>(private_key), sizeof(private_key)); |
| } |
| |
| bool Curve25519KeyExchange::CalculateSharedKey( |
| const StringPiece& peer_public_value, |
| string* out_result) const { |
| if (peer_public_value.size() != crypto::curve25519::kBytes) { |
| return false; |
| } |
| |
| uint8 result[crypto::curve25519::kBytes]; |
| crypto::curve25519::ScalarMult( |
| private_key_, |
| reinterpret_cast<const uint8*>(peer_public_value.data()), |
| result); |
| out_result->assign(reinterpret_cast<char*>(result), sizeof(result)); |
| |
| return true; |
| } |
| |
| StringPiece Curve25519KeyExchange::public_value() const { |
| return StringPiece(reinterpret_cast<const char*>(public_key_), |
| sizeof(public_key_)); |
| } |
| |
| CryptoTag Curve25519KeyExchange::tag() const { |
| return kC255; |
| } |
| |
| } // namespace net |