cryptohome: Move Encrypt/DecryptWithSystemSalt() out of CryptohomeLibrary

chromeos/cryptohome/cryptohome_library.h

 // 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.
 
 #ifndef CHROMEOS_CRYPTOHOME_CRYPTOHOME_LIBRARY_H_
 #define CHROMEOS_CRYPTOHOME_CRYPTOHOME_LIBRARY_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "chromeos/chromeos_export.h"
 
 namespace chromeos {
 
 // This interface defines the interaction with the ChromeOS cryptohome library
 // APIs.
 class CHROMEOS_EXPORT CryptohomeLibrary {

[satorux1, 2013/10/04 06:44:01]

BTW, now this class just manages the system salt. we should rename this to
something like SystemSaltGetter

  public:
   // Manage an explicitly initialized global instance.
   static void Initialize();
   static bool IsInitialized();
   static void Shutdown();
   static CryptohomeLibrary* Get();
 
   // Sets up Get() to return |impl| for testing (e.g. with a mock
   // implementation). Call SetForTest(NULL) when |impl| is deleted.
   static void SetForTest(CryptohomeLibrary* impl);
 
   // Returns a CryptohomeLibrary instance for testing. Does not set or affect
   // the global instance.
   static CryptohomeLibrary* GetTestImpl();
 
   // Public so that result of GetTestImpl can be destroyed.
   virtual ~CryptohomeLibrary();
 
   // Returns system hash in hex encoded ascii format. Note: this may return
   // an empty string (e.g. if cryptohome is not running). It is up to the
   // calling function to try again after a delay if desired.
+  //
+  // TODO(hashimoto): Make it asynchronous. crbug.com/141009.
   virtual std::string GetSystemSalt() = 0;
 
-  // Encrypts |token| with the system salt key (stable for the lifetime
-  // of the device).  Useful to avoid storing plain text in place like
-  // Local State.
-  virtual std::string EncryptWithSystemSalt(const std::string& token) = 0;
-
-  // Decrypts |token| with the system salt key (stable for the lifetime
-  // of the device).
-  virtual std::string DecryptWithSystemSalt(
-      const std::string& encrypted_token_hex) = 0;
+  // Returns system hash in hex encoded ascii format, cached by a prior call
+  // to GetSystemSalt(). Note: this may return an empty string (e.g. if
+  // GetSystemSalt() is not yet called).
+  virtual std::string GetCachedSystemSalt() = 0;
 
  protected:
   CryptohomeLibrary();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CryptohomeLibrary);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_CRYPTOHOME_CRYPTOHOME_LIBRARY_H_