[Athena] Extract Chrome OS authentication stack

chrome/browser/chromeos/login/auth/key.h

-// Copyright 2014 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.
-
-#ifndef CHROME_BROWSER_CHROMEOS_LOGIN_AUTH_KEY_H_
-#define CHROME_BROWSER_CHROMEOS_LOGIN_AUTH_KEY_H_
-
-#include <string>
-
-namespace chromeos {
-
-// Key for user authentication. The class supports hashing of plain text
-// passwords to generate keys as well as the use of pre-hashed keys.
-class Key {
- public:
-  enum KeyType {
-    // Plain text password.
-    KEY_TYPE_PASSWORD_PLAIN,
-    // SHA256 of salt + password, first half only, lower-case hex encoded.
-    KEY_TYPE_SALTED_SHA256_TOP_HALF,
-    // PBKDF2 with 256 bit AES and 1234 iterations, base64 encoded.
-    KEY_TYPE_SALTED_PBKDF2_AES256_1234,
-  };
-
-  Key();
-  Key(const Key& other);
-  explicit Key(const std::string& plain_text_password);
-  Key(KeyType key_type, const std::string& salt, const std::string& secret);
-  ~Key();
-
-  bool operator==(const Key& other) const;
-
-  KeyType GetKeyType() const;
-  const std::string& GetSecret() const;
-  const std::string& GetLabel() const;
-
-  void SetLabel(const std::string& label);
-
-  void ClearSecret();
-
-  void Transform(KeyType target_key_type, const std::string& salt);
-
- private:
-  KeyType key_type_;
-  std::string salt_;
-  std::string secret_;
-  std::string label_;
-};
-
-}  // namespace chromeos
-
-#endif  // CHROME_BROWSER_CHROMEOS_LOGIN_AUTH_KEY_H_