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.
5 #ifndef NET_QUIC_CRYPTO_QUIC_ENCRYPTER_H_
6 #define NET_QUIC_CRYPTO_QUIC_ENCRYPTER_H_
8 #include "net/base/net_export.h"
9 #include "net/quic/crypto/crypto_protocol.h"
10 #include "net/quic/quic_protocol.h"
14 class NET_EXPORT_PRIVATE QuicEncrypter {
16 virtual ~QuicEncrypter() {}
18 static QuicEncrypter* Create(QuicTag algorithm);
20 // Sets the encryption key. Returns true on success, false on failure.
22 // NOTE: The key is the client_write_key or server_write_key derived from
24 virtual bool SetKey(base::StringPiece key) = 0;
26 // Sets the fixed initial bytes of the nonce. Returns true on success,
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.
33 // <------------ 64 bits ----------->
34 // +---------------------+----------------------------------+
35 // | Fixed prefix | Packet sequence number |
36 // +---------------------+----------------------------------+
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;
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;
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;
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.
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;
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;
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;
80 // For use by unit tests only.
81 virtual base::StringPiece GetKey() const = 0;
82 virtual base::StringPiece GetNoncePrefix() const = 0;
87 #endif // NET_QUIC_CRYPTO_QUIC_ENCRYPTER_H_