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 23 namespace net { 24 25 // P256KeyExchange implements a KeyExchange using elliptic-curve 26 // Diffie-Hellman on NIST P-256. 27 class 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