Keep only base/extractor.[cc|h].

base/security/challenger.h

-// Copyright 2007-2009 Google Inc.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-// ========================================================================
-
-#ifndef OMAHA_COMMON_SECURITY_CHALLENGER_H__
-#define OMAHA_COMMON_SECURITY_CHALLENGER_H__
-
-#include <inttypes.h>
-
-#include "md5.h"
-#include "aes.h"
-#include "rsa.h"
-
-class Challenger {
- public:
-  // Instantiate internal PRNG with seed. Use a proper method on your
-  // target platform to collect some entropy. For windows for instance,
-  // use CryptoAPI; on unix, read some from /dev/urandom.
-  // 128 bits of entropy is plenty.
-  explicit Challenger(RSA::PublicKey public_key,
-                      const uint8_t* seed, int seed_size);
-
-  // Not a const method! Every call updates internal state and never
-  // are identical challenges returned.
-  // Returns WebSafe base64 encoded string.
-  const char* challenge();
-
-  // Verifies whether signature contains current challenge and hash.
-  // Arguments are expected to be WebSafe base64 encoded strings.
-  bool verify(const char* hash, const char* signature) const;
-
- private:
-  char challenge_[64];
-  uint8_t count_[AES_BLOCK_SIZE];
-  uint8_t seed_[MD5_DIGEST_SIZE];
-  RSA rsa_;
-};
-
-#endif  // OMAHA_COMMON_SECURITY_CHALLENGER_H__