chrome/browser/profile_resetter/jtl_foundation.cc

   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
  11 namespace jtl_foundation {
  12
  13 Hasher::Hasher(const std::string& seed) : hmac_(crypto::HMAC::SHA256) {
  14   if (!hmac_.Init(seed))
  15     NOTREACHED();
  16 }
  17
  18 Hasher::~Hasher() {}
  19
  20 std::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
  37 bool 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 (!base::IsHexDigit(*it))
  43       return false;
  44   }
  45   return true;
  46 }
  47
  48 }  // namespace jtl_foundation