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_DECRYPTER_H_
6 #define NET_QUIC_CRYPTO_QUIC_DECRYPTER_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 QuicDecrypter {
16 virtual ~QuicDecrypter() {}
18 static QuicDecrypter* 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 // 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
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;
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()
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;
65 // For use by unit tests only.
66 virtual base::StringPiece GetKey() const = 0;
67 virtual base::StringPiece GetNoncePrefix() const = 0;
72 #endif // NET_QUIC_CRYPTO_QUIC_DECRYPTER_H_