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      1 // Copyright 2014 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_CHACHA20_POLY1305_ENCRYPTER_H_
      6 #define NET_QUIC_CRYPTO_CHACHA20_POLY1305_ENCRYPTER_H_
      7 
      8 #include "net/quic/crypto/aead_base_encrypter.h"
      9 
     10 namespace net {
     11 
     12 // A ChaCha20Poly1305Encrypter is a QuicEncrypter that implements the
     13 // AEAD_CHACHA20_POLY1305 algorithm specified in
     14 // draft-agl-tls-chacha20poly1305-04, except that it truncates the Poly1305
     15 // authenticator to 12 bytes. Create an instance by calling
     16 // QuicEncrypter::Create(kCC12).
     17 //
     18 // It uses an authentication tag of 16 bytes (128 bits). There is no
     19 // fixed nonce prefix.
     20 class NET_EXPORT_PRIVATE ChaCha20Poly1305Encrypter : public AeadBaseEncrypter {
     21  public:
     22   enum {
     23     kAuthTagSize = 12,
     24   };
     25 
     26   ChaCha20Poly1305Encrypter();
     27   virtual ~ChaCha20Poly1305Encrypter();
     28 
     29   // Returns true if the underlying crypto library supports ChaCha20+Poly1305.
     30   static bool IsSupported();
     31 
     32 #if !defined(USE_OPENSSL)
     33  protected:
     34   // AeadBaseEncrypter methods:
     35   virtual void FillAeadParams(base::StringPiece nonce,
     36                               base::StringPiece associated_data,
     37                               size_t auth_tag_size,
     38                               AeadParams* aead_params) const OVERRIDE;
     39 #endif
     40 
     41  private:
     42   DISALLOW_COPY_AND_ASSIGN(ChaCha20Poly1305Encrypter);
     43 };
     44 
     45 }  // namespace net
     46 
     47 #endif  // NET_QUIC_CRYPTO_CHACHA20_POLY1305_ENCRYPTER_H_
     48