encrypt (ActiveSupport::MessageEncryptor)

    # File lib/active_support/message_encryptor.rb, line 20
        def encrypt(value)
          cipher = new_cipher
          # Rely on OpenSSL for the initialization vector
          iv = cipher.random_iv

          cipher.encrypt
          cipher.key = @secret
          cipher.iv  = iv

          encrypted_data = cipher.update(Marshal.dump(value))
          encrypted_data << cipher.final

          [encrypted_data, iv].map {|v| ActiveSupport::Base64.encode64s(v)}.join("--")
        end