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/quic_protocol.h"
13 class NET_EXPORT_PRIVATE QuicEncrypter
{
15 virtual ~QuicEncrypter() {}
17 static QuicEncrypter
* Create(QuicTag algorithm
);
19 // Sets the encryption key. Returns true on success, false on failure.
21 // NOTE: The key is the client_write_key or server_write_key derived from
23 virtual bool SetKey(base::StringPiece key
) = 0;
25 // Sets the fixed initial bytes of the nonce. Returns true on success,
28 // NOTE: The nonce prefix is the client_write_iv or server_write_iv
29 // derived from the master secret. A 64-bit packet sequence number will
30 // be appended to form the nonce.
32 // <------------ 64 bits ----------->
33 // +---------------------+----------------------------------+
34 // | Fixed prefix | Packet sequence number |
35 // +---------------------+----------------------------------+
38 // The security of the nonce format requires that QUIC never reuse a
39 // packet sequence number, even when retransmitting a lost packet.
40 virtual bool SetNoncePrefix(base::StringPiece nonce_prefix
) = 0;
42 // Encrypt encrypts |plaintext| and writes the ciphertext, plus a MAC over
43 // both |associated_data| and |plaintext| to |output|, using |nonce| as the
44 // nonce. |nonce| must be |8+GetNoncePrefixSize()| bytes long and |output|
45 // must point to a buffer that is at least
46 // |GetCiphertextSize(plaintext.size()| bytes long.
47 virtual bool Encrypt(base::StringPiece nonce
,
48 base::StringPiece associated_data
,
49 base::StringPiece plaintext
,
50 unsigned char* output
) = 0;
52 // Returns a newly created QuicData object containing the encrypted
53 // |plaintext| as well as a MAC over both |plaintext| and |associated_data|,
54 // or nullptr if there is an error. |sequence_number| is appended to the
55 // |nonce_prefix| value provided in SetNoncePrefix() to form the nonce.
56 virtual bool EncryptPacket(QuicPacketSequenceNumber sequence_number
,
57 base::StringPiece associated_data
,
58 base::StringPiece plaintext
,
60 size_t* output_length
,
61 size_t max_output_length
) = 0;
63 // GetKeySize() and GetNoncePrefixSize() tell the HKDF class how many bytes
64 // of key material needs to be derived from the master secret.
65 // NOTE: the sizes returned by GetKeySize() and GetNoncePrefixSize() are
66 // also correct for the QuicDecrypter of the same algorithm. So only
67 // QuicEncrypter has these two methods.
69 // Returns the size in bytes of a key for the algorithm.
70 virtual size_t GetKeySize() const = 0;
71 // Returns the size in bytes of the fixed initial part of the nonce.
72 virtual size_t GetNoncePrefixSize() const = 0;
74 // Returns the maximum length of plaintext that can be encrypted
75 // to ciphertext no larger than |ciphertext_size|.
76 virtual size_t GetMaxPlaintextSize(size_t ciphertext_size
) const = 0;
78 // Returns the length of the ciphertext that would be generated by encrypting
79 // to plaintext of size |plaintext_size|.
80 virtual size_t GetCiphertextSize(size_t plaintext_size
) const = 0;
82 // For use by unit tests only.
83 virtual base::StringPiece
GetKey() const = 0;
84 virtual base::StringPiece
GetNoncePrefix() const = 0;
89 #endif // NET_QUIC_CRYPTO_QUIC_ENCRYPTER_H_