Remove AccessVerifier interface.

remoting/host/host_secret.cc

+// Copyright (c) 2011 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 "remoting/host/host_secret.h"
+
+#include <vector>
+
+#include "base/logging.h"
+#include "base/rand_util.h"
+
+namespace remoting {
+
+namespace {
+
+// 5 digits means 100K possible host secrets with uniform distribution, which
+// should be enough for short-term passwords, given that we rate-limit guesses
+// in the cloud and expire access codes after a small number of attempts.
+const int kHostSecretLength = 5;
+const char kHostSecretAlphabet[] = "0123456789";

[Wez, 2011/11/29 05:58:47]

Now that the alphabet for codes is 0-9, we could just call
CryptoRandomInt(10**5) and stringify that.

[Sergey Ulanov, 2011/11/29 18:52:01]

Done.

+
+// Generates cryptographically strong random number in the range [0, max).
+int CryptoRandomInt(int max) {
+  uint32 random_int32;
+  base::RandBytes(&random_int32, sizeof(random_int32));
+  return random_int32 % max;
+}
+
+}  // namespace
+
+std::string GenerateRandomHostSecret() {
+  std::vector<char> result;

[Wez, 2011/11/29 05:58:47]

Can't we just create the string and generate random data into it, rather than
going via a vector?

[Sergey Ulanov, 2011/11/29 18:52:01]

Done.

+  int alphabet_size = strlen(kHostSecretAlphabet);
+  result.resize(kHostSecretLength);
+  for (int i = 0; i < kHostSecretLength; ++i) {
+    result[i] = kHostSecretAlphabet[CryptoRandomInt(alphabet_size)];
+  }
+  return std::string(result.begin(), result.end());
+}
+
+}  // namespace remoting