Change mojo demo apps to use Application.
[chromium-blink-merge.git] / crypto / hkdf.h
blob1d7a87673a1d7be7c9d95b18e490e485f59d8957
1 // Copyright (c) 2013 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 CRYPTO_HKDF_H_
6 #define CRYPTO_HKDF_H_
8 #include <vector>
10 #include "base/basictypes.h"
11 #include "base/memory/scoped_ptr.h"
12 #include "base/strings/string_piece.h"
13 #include "build/build_config.h"
14 #include "crypto/crypto_export.h"
16 namespace crypto {
18 // HKDF implements the key derivation function specified in RFC 5869 (using
19 // SHA-256) and outputs key material, as needed by QUIC.
20 // See https://tools.ietf.org/html/rfc5869 for details.
21 class CRYPTO_EXPORT HKDF {
22 public:
23 // |secret|: The input shared secret (or, from RFC 5869, the IKM).
24 // |salt|: an (optional) public salt / non-secret random value. While
25 // optional, callers are strongly recommended to provide a salt. There is no
26 // added security value in making this larger than the SHA-256 block size of
27 // 64 bytes.
28 // |info|: an (optional) label to distinguish different uses of HKDF. It is
29 // optional context and application specific information (can be a zero-length
30 // string).
31 // |key_bytes_to_generate|: the number of bytes of key material to generate.
32 // |iv_bytes_to_generate|: the number of bytes of IV to generate.
33 HKDF(const base::StringPiece& secret,
34 const base::StringPiece& salt,
35 const base::StringPiece& info,
36 size_t key_bytes_to_generate,
37 size_t iv_bytes_to_generate);
38 ~HKDF();
40 base::StringPiece client_write_key() const {
41 return client_write_key_;
43 base::StringPiece client_write_iv() const {
44 return client_write_iv_;
46 base::StringPiece server_write_key() const {
47 return server_write_key_;
49 base::StringPiece server_write_iv() const {
50 return server_write_iv_;
53 private:
54 std::vector<uint8> output_;
56 base::StringPiece client_write_key_;
57 base::StringPiece server_write_key_;
58 base::StringPiece client_write_iv_;
59 base::StringPiece server_write_iv_;
62 } // namespace crypto
64 #endif // CRYPTO_HKDF_H_