1 // Copyright (c) 2012 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_QUIC_DECRYPTER_H_ 6 #define NET_QUIC_CRYPTO_QUIC_DECRYPTER_H_ 7 8 #include "net/base/net_export.h" 9 #include "net/quic/crypto/crypto_protocol.h" 10 #include "net/quic/quic_protocol.h" 11 12 namespace net { 13 14 class NET_EXPORT_PRIVATE QuicDecrypter { 15 public: 16 virtual ~QuicDecrypter() {} 17 18 static QuicDecrypter* Create(QuicTag algorithm); 19 20 // Sets the encryption key. Returns true on success, false on failure. 21 // 22 // NOTE: The key is the client_write_key or server_write_key derived from 23 // the master secret. 24 virtual bool SetKey(base::StringPiece key) = 0; 25 26 // Sets the fixed initial bytes of the nonce. Returns true on success, 27 // false on failure. 28 // 29 // NOTE: The nonce prefix is the client_write_iv or server_write_iv 30 // derived from the master secret. A 64-bit packet sequence number will 31 // be appended to form the nonce. 32 // 33 // <------------ 64 bits -----------> 34 // +---------------------+----------------------------------+ 35 // | Fixed prefix | Packet sequence number | 36 // +---------------------+----------------------------------+ 37 // Nonce format 38 // 39 // The security of the nonce format requires that QUIC never reuse a 40 // packet sequence number, even when retransmitting a lost packet. 41 virtual bool SetNoncePrefix(base::StringPiece nonce_prefix) = 0; 42 43 // Decrypt authenticates |associated_data| and |ciphertext| and then decrypts 44 // |ciphertext| into |output|, using |nonce|. |nonce| must be 8 bytes longer 45 // than the nonce prefix length returned by GetNoncePrefixSize() (of the 46 // encrypter). |output| must be as long as |ciphertext| on entry and, on 47 // successful return, the true length of the plaintext will be written to 48 // |*output_length|. 49 virtual bool Decrypt(base::StringPiece nonce, 50 base::StringPiece associated_data, 51 base::StringPiece ciphertext, 52 unsigned char* output, 53 size_t* output_length) = 0; 54 55 // Returns a newly created QuicData object containing the decrypted 56 // |ciphertext| or NULL if there is an error. |sequence_number| is 57 // appended to the |nonce_prefix| value provided in SetNoncePrefix() 58 // to form the nonce. 59 // TODO(wtc): add a way for DecryptPacket to report decryption failure due 60 // to non-authentic inputs, as opposed to other reasons for failure. 61 virtual QuicData* DecryptPacket(QuicPacketSequenceNumber sequence_number, 62 base::StringPiece associated_data, 63 base::StringPiece ciphertext) = 0; 64 65 // For use by unit tests only. 66 virtual base::StringPiece GetKey() const = 0; 67 virtual base::StringPiece GetNoncePrefix() const = 0; 68 }; 69 70 } // namespace net 71 72 #endif // NET_QUIC_CRYPTO_QUIC_DECRYPTER_H_ 73
