blob: c9a2b74d983ed8f931bb57f8f820b4548c10ae20 [file] [log] [blame]
James Robinson646469d2014-10-03 15:33:28 -07001// 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#include "crypto/hmac.h"
6
7#include <algorithm>
8
9#include "base/logging.h"
10#include "crypto/secure_util.h"
11#include "crypto/symmetric_key.h"
12
13namespace crypto {
14
15bool HMAC::Init(SymmetricKey* key) {
16 std::string raw_key;
17 bool result = key->GetRawKey(&raw_key) && Init(raw_key);
18 // Zero out key copy. This might get optimized away, but one can hope.
19 // Using std::string to store key info at all is a larger problem.
20 std::fill(raw_key.begin(), raw_key.end(), 0);
21 return result;
22}
23
24size_t HMAC::DigestLength() const {
25 switch (hash_alg_) {
26 case SHA1:
27 return 20;
28 case SHA256:
29 return 32;
30 default:
31 NOTREACHED();
32 return 0;
33 }
34}
35
36bool HMAC::Verify(const base::StringPiece& data,
37 const base::StringPiece& digest) const {
38 if (digest.size() != DigestLength())
39 return false;
40 return VerifyTruncated(data, digest);
41}
42
43bool HMAC::VerifyTruncated(const base::StringPiece& data,
44 const base::StringPiece& digest) const {
45 if (digest.empty())
46 return false;
47 size_t digest_length = DigestLength();
48 scoped_ptr<unsigned char[]> computed_digest(
49 new unsigned char[digest_length]);
50 if (!Sign(data, computed_digest.get(), digest_length))
51 return false;
52
53 return SecureMemEqual(digest.data(), computed_digest.get(),
54 std::min(digest.size(), digest_length));
55}
56
57} // namespace crypto