1// Copyright 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.
4
5#include "chrome/browser/profile_resetter/jtl_foundation.h"
6
7#include "base/logging.h"
8#include "base/strings/string_number_conversions.h"
9#include "base/strings/string_util.h"
10
11namespace jtl_foundation {
12
13Hasher::Hasher(const std::string& seed) : hmac_(crypto::HMAC::SHA256) {
14  if (!hmac_.Init(seed))
15    NOTREACHED();
16}
17
18Hasher::~Hasher() {}
19
20std::string Hasher::GetHash(const std::string& input) const {
21  if (cached_hashes_.find(input) == cached_hashes_.end()) {
22    // Calculate value.
23    unsigned char digest[kHashSizeInBytes];
24    if (!hmac_.Sign(input, digest, arraysize(digest))) {
25      NOTREACHED();
26      return std::string();
27    }
28    // Instead of using the full SHA256, we only use the hex encoding of the
29    // first 16 bytes.
30    cached_hashes_[input] = base::HexEncode(digest, kHashSizeInBytes / 2);
31    DCHECK_EQ(kHashSizeInBytes, cached_hashes_[input].size());
32  }
33  return cached_hashes_[input];
34}
35
36// static
37bool Hasher::IsHash(const std::string& maybe_hash) {
38  if (maybe_hash.size() != kHashSizeInBytes)
39    return false;
40  for (std::string::const_iterator it = maybe_hash.begin();
41       it != maybe_hash.end(); ++it) {
42    if (!IsHexDigit(*it))
43      return false;
44  }
45  return true;
46}
47
48}  // namespace jtl_foundation
49