text: // 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.
  
  #ifndef NET_QUIC_CRYPTO_CURVE25519_KEY_EXCHANGE_H_
  #define NET_QUIC_CRYPTO_CURVE25519_KEY_EXCHANGE_H_
  
  #include <string>
  
  #include "base/compiler_specific.h"
  #include "base/strings/string_piece.h"
  #include "net/base/net_export.h"
  #include "net/quic/crypto/key_exchange.h"
  
  namespace net {
  
  class QuicRandom;
  
  // Curve25519KeyExchange implements a KeyExchange using elliptic-curve
  // Diffie-Hellman on curve25519. See http://cr.yp.to/ecdh.html
  class NET_EXPORT_PRIVATE Curve25519KeyExchange : public KeyExchange {
   public:
    ~Curve25519KeyExchange() override;
  
    // New creates a new object from a private key. If the private key is
    // invalid, nullptr is returned.
    static Curve25519KeyExchange* New(const base::StringPiece& private_key);
  
    // NewPrivateKey returns a private key, generated from |rand|, suitable for
    // passing to |New|.
    static std::string NewPrivateKey(QuicRandom* rand);
  
    // KeyExchange interface.
    KeyExchange* NewKeyPair(QuicRandom* rand) const override;
    bool CalculateSharedKey(const base::StringPiece& peer_public_value,
                            std::string* shared_key) const override;
    base::StringPiece public_value() const override;
    QuicTag tag() const override;
  
   private:
    Curve25519KeyExchange();
  
    uint8 private_key_[32];
    uint8 public_key_[32];
  };
  
  }  // namespace net
  
  #endif  // NET_QUIC_CRYPTO_CURVE25519_KEY_EXCHANGE_H_
  