1// Copyright (c) 2013 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef NET_QUIC_CRYPTO_P256_KEY_EXCHANGE_H_ 6#define NET_QUIC_CRYPTO_P256_KEY_EXCHANGE_H_ 7 8#include <string> 9 10#include "base/memory/scoped_ptr.h" 11#include "base/strings/string_piece.h" 12#include "net/base/net_export.h" 13#include "net/quic/crypto/key_exchange.h" 14 15#if defined(USE_OPENSSL) 16#include "crypto/openssl_util.h" 17#include "crypto/scoped_openssl_types.h" 18#else 19#include "crypto/ec_private_key.h" 20#include "crypto/scoped_nss_types.h" 21#endif 22 23namespace net { 24 25// P256KeyExchange implements a KeyExchange using elliptic-curve 26// Diffie-Hellman on NIST P-256. 27class NET_EXPORT_PRIVATE P256KeyExchange : public KeyExchange { 28 public: 29 virtual ~P256KeyExchange(); 30 31 // New creates a new key exchange object from a private key. If 32 // |private_key| is invalid, NULL is returned. 33 static P256KeyExchange* New(base::StringPiece private_key); 34 35 // |NewPrivateKey| returns a private key, suitable for passing to |New|. 36 // If |NewPrivateKey| can't generate a private key, it returns an empty 37 // string. 38 static std::string NewPrivateKey(); 39 40 // KeyExchange interface. 41 virtual KeyExchange* NewKeyPair(QuicRandom* rand) const OVERRIDE; 42 virtual bool CalculateSharedKey(const base::StringPiece& peer_public_value, 43 std::string* shared_key) const OVERRIDE; 44 virtual base::StringPiece public_value() const OVERRIDE; 45 virtual QuicTag tag() const OVERRIDE; 46 47 private: 48 enum { 49 // A P-256 field element consists of 32 bytes. 50 kP256FieldBytes = 32, 51 // A P-256 point in uncompressed form consists of 0x04 (to denote 52 // that the point is uncompressed) followed by two, 32-byte field 53 // elements. 54 kUncompressedP256PointBytes = 1 + 2 * kP256FieldBytes, 55 // The first byte in an uncompressed P-256 point. 56 kUncompressedECPointForm = 0x04, 57 }; 58 59#if defined(USE_OPENSSL) 60 // P256KeyExchange takes ownership of |private_key|, and expects 61 // |public_key| consists of |kUncompressedP256PointBytes| bytes. 62 P256KeyExchange(EC_KEY* private_key, const uint8* public_key); 63 64 crypto::ScopedEC_KEY private_key_; 65#else 66 // P256KeyExchange takes ownership of |key_pair|, and expects 67 // |public_key| consists of |kUncompressedP256PointBytes| bytes. 68 P256KeyExchange(crypto::ECPrivateKey* key_pair, const uint8* public_key); 69 70 scoped_ptr<crypto::ECPrivateKey> key_pair_; 71#endif 72 // The public key stored as an uncompressed P-256 point. 73 uint8 public_key_[kUncompressedP256PointBytes]; 74 75 DISALLOW_COPY_AND_ASSIGN(P256KeyExchange); 76}; 77 78} // namespace net 79#endif // NET_QUIC_CRYPTO_P256_KEY_EXCHANGE_H_ 80 81