Added crypto random-number generator

sync/util/nigori.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sync/util/nigori.h"
 
 #include <sstream>
 #include <vector>
 
 #include "base/base64.h"
 #include "base/logging.h"
-#include "base/rand_util.h"
 #include "base/string_util.h"
 #include "base/sys_byteorder.h"
 #include "crypto/encryptor.h"
 #include "crypto/hmac.h"
+#include "crypto/random.h"
 #include "crypto/symmetric_key.h"
 
 using base::Base64Encode;
 using base::Base64Decode;
-using base::RandInt;
 using crypto::Encryptor;
 using crypto::HMAC;
 using crypto::SymmetricKey;
 
 namespace syncer {
 
 // NigoriStream simplifies the concatenation operation of the Nigori protocol.
 class NigoriStream {
  public:
   // Append the big-endian representation of the length of |value| with 32 bits,
@@ skipping 115 matching lines @@
   if (!hmac.Sign(ciphertext, &hash[0], hash.size()))
     return false;
 
   std::string output;
   output.assign(ciphertext);
   output.append(hash.begin(), hash.end());
 
   return Base64Encode(output, permuted);
 }
 
-std::string GenerateRandomString(size_t size) {
-  // TODO(albertb): Use a secure random function.
-  std::string random(size, 0);
-  for (size_t i = 0; i < size; ++i)
-    random[i] = RandInt(0, 0xff);
-  return random;
-}
-
 // Enc[Kenc,Kmac](value)
 bool Nigori::Encrypt(const std::string& value, std::string* encrypted) const {
   if (0U >= value.size())
     return false;
 
-  std::string iv = GenerateRandomString(kIvSize);
+  std::string iv;
+  crypto::RandBytes(base::WriteInto(&iv, kIvSize + 1), kIvSize);
 
   Encryptor encryptor;
   if (!encryptor.Init(encryption_key_.get(), Encryptor::CBC, iv))
     return false;
 
   std::string ciphertext;
   if (!encryptor.Encrypt(value, &ciphertext))
     return false;
 
   std::string raw_mac_key;
@@ skipping 67 matching lines @@
   DCHECK(user_key);
   DCHECK(encryption_key);
   DCHECK(mac_key);
 
   return user_key_->GetRawKey(user_key) &&
       encryption_key_->GetRawKey(encryption_key) &&
       mac_key_->GetRawKey(mac_key);
 }
 
 }  // namespace syncer