说明：  其具体实现如下： 设Ek()和Dk()代表DES算法的加密和解密过程，K代表DES算法使用的密钥，P代表明文，C代表密文，这样： 3DES加密过程为：C=Ek3(Dk2(Ek1(P))) 3DES解密过程为：P=Dk1(EK2(Dk3(C))) 3DES又称Triple DES，是DES加密算法的一种模式，它使用3条56位的密钥对数据进行三次加密。DES使用56位密钥和密码块的方法，而在密码块的方法中，文本被分成64位大小的文本块然后再进行加密。比起最初的DES，3DES更为安全。 3DES（即Triple DES）是DES向AES过渡的加密算法（1999年，NIST将3-DES指定为过渡的加密标准），是DES的一个更安全的变形。它以DES为基本模块，通过组合分组方法设计出分组加密算法.
( its implementation is as follows: Let Ek () and Dk () the process of encryption and decryption algorithm on behalf of DES, K on behalf of DES algorithm using key, P represents the plaintext, ciphertext C representative, such: 3DES encryption process is: C=Ek3 (Dk2 (Ek1 (P))) 3DES decryption process: P=Dk1 (EK2 (Dk3 (C))) 3DES is also called Triple DES, is a kind of mode of DES encryption algorithm, it uses 3 56 bit key for the three time on data encryption. DES uses 56 bit key and cipher block method, in the method code block, the text is divided into 64 size of the block of text and then encrypt. Compared with the original DES, 3DES is more secure. 3DES (Triple DES) is a DES to AES transition encryption algorithm (1999, NIST 3-DES will be designated as the transition of the encryption standard), is a more secure deformation DES. It takes DES as the basic module, through the design of block cipher algorithm combined the grouping method,)