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_ENCRYPTER_H_ 6 #define NET_QUIC_CRYPTO_QUIC_ENCRYPTER_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 QuicEncrypter { 15 public: 16 virtual ~QuicEncrypter() {} 17 18 static QuicEncrypter* 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 // Encrypt encrypts |plaintext| and writes the ciphertext, plus a MAC over 44 // both |associated_data| and |plaintext| to |output|, using |nonce| as the 45 // nonce. |nonce| must be |8+GetNoncePrefixSize()| bytes long and |output| 46 // must point to a buffer that is at least 47 // |GetCiphertextSize(plaintext.size()| bytes long. 48 virtual bool Encrypt(base::StringPiece nonce, 49 base::StringPiece associated_data, 50 base::StringPiece plaintext, 51 unsigned char* output) = 0; 52 53 // Returns a newly created QuicData object containing the encrypted 54 // |plaintext| as well as a MAC over both |plaintext| and |associated_data|, 55 // or NULL if there is an error. |sequence_number| is appended to the 56 // |nonce_prefix| value provided in SetNoncePrefix() to form the nonce. 57 virtual QuicData* EncryptPacket(QuicPacketSequenceNumber sequence_number, 58 base::StringPiece associated_data, 59 base::StringPiece plaintext) = 0; 60 61 // GetKeySize() and GetNoncePrefixSize() tell the HKDF class how many bytes 62 // of key material needs to be derived from the master secret. 63 // NOTE: the sizes returned by GetKeySize() and GetNoncePrefixSize() are 64 // also correct for the QuicDecrypter of the same algorithm. So only 65 // QuicEncrypter has these two methods. 66 67 // Returns the size in bytes of a key for the algorithm. 68 virtual size_t GetKeySize() const = 0; 69 // Returns the size in bytes of the fixed initial part of the nonce. 70 virtual size_t GetNoncePrefixSize() const = 0; 71 72 // Returns the maximum length of plaintext that can be encrypted 73 // to ciphertext no larger than |ciphertext_size|. 74 virtual size_t GetMaxPlaintextSize(size_t ciphertext_size) const = 0; 75 76 // Returns the length of the ciphertext that would be generated by encrypting 77 // to plaintext of size |plaintext_size|. 78 virtual size_t GetCiphertextSize(size_t plaintext_size) const = 0; 79 80 // For use by unit tests only. 81 virtual base::StringPiece GetKey() const = 0; 82 virtual base::StringPiece GetNoncePrefix() const = 0; 83 }; 84 85 } // namespace net 86 87 #endif // NET_QUIC_CRYPTO_QUIC_ENCRYPTER_H_ 88
