_encrypt

# File activesupport/lib/active_support/message_encryptor.rb, line 64
    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(@serializer.dump(value))
      encrypted_data << cipher.final

      [encrypted_data, iv].map {|v| ::Base64.strict_encode64(v)}.join("--")
    end