说明：  RC522射频卡读写驱动和应用，MSP430单片机调试成功并且加入了DES加密算法，卡数据通信时可以选择是否加密，此程序仅供参考。
(RC522 RF card reader drivers and applications, MSP430 MCU debugging success and joined the DES encryption algorithm, data communication card, you can choose whether to encrypt, this program is for reference only.whether to encrypt the card data communication, this program is for reference only.)