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      1 // Copyright (c) 2010 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/sync/util/crypto_helpers.h"
      6 
      7 #include <string>
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/format_macros.h"
     12 #include "base/logging.h"
     13 #include "base/base64.h"
     14 #include "base/rand_util.h"
     15 #include "base/string_number_conversions.h"
     16 #include "base/string_util.h"
     17 
     18 using std::string;
     19 using std::vector;
     20 
     21 MD5Calculator::MD5Calculator() {
     22   MD5Init(&context_);
     23 }
     24 
     25 MD5Calculator::~MD5Calculator() {}
     26 
     27 void MD5Calculator::AddData(const unsigned char* data, int length) {
     28   CHECK(bin_digest_.empty());
     29   MD5Update(&context_, data, length);
     30 }
     31 
     32 void MD5Calculator::CalcDigest() {
     33   if (bin_digest_.empty()) {
     34     MD5Digest digest;
     35     MD5Final(&digest, &context_);
     36     bin_digest_.assign(digest.a, digest.a + arraysize(digest.a));
     37   }
     38 }
     39 
     40 const vector<uint8>& MD5Calculator::GetDigest() {
     41   CalcDigest();
     42   return bin_digest_;
     43 }
     44 
     45 std::string MD5Calculator::GetHexDigest() {
     46   CalcDigest();
     47   string hex = base::HexEncode(reinterpret_cast<char*>(&bin_digest_.front()),
     48                                bin_digest_.size());
     49   StringToLowerASCII(&hex);
     50   return hex;
     51 }
     52 
     53 void GetRandomBytes(char* output, int output_length) {
     54   uint64 random_int;
     55   const char* random_int_bytes = reinterpret_cast<const char*>(&random_int);
     56   int random_int_size = sizeof(random_int);
     57   for (int i = 0; i < output_length; i += random_int_size) {
     58     random_int = base::RandUint64();
     59     int copy_count = std::min(output_length - i, random_int_size);
     60     memcpy(output + i, random_int_bytes, copy_count);
     61   }
     62 }
     63 
     64 string Generate128BitRandomHexString() {
     65   const int kNumberBytes = 128 / 8;
     66   std::string random_bytes(kNumberBytes, ' ');
     67   GetRandomBytes(&random_bytes[0], kNumberBytes);
     68   std::string base64_encoded_bytes;
     69   base::Base64Encode(random_bytes, &base64_encoded_bytes);
     70   return base64_encoded_bytes;
     71 }
     72