The Data Encryption System (DES) is a cryptographic algorithm approved by the Federal Information Processing Standards (FIPS) for encrypting and decrypting binary code information (Data, 1988). Enciphering and deciphering operations are based on a binary number called a key. The key consists of 64 binary digits which are either "O"s or "I"s. Fifty-six bits are randomly generated and used directly in the algorithm, and the remaining 8 are used for error detection. They make each 8-bit byte of the key odd. Authorized users of encrypted computer data need the key used to encrypt the data to decipher it. The algorithm in this standard is known by people who use this standard, but the use of a unique key makes the algorithm unique. Unauthorized recipients cannot decrypt the data unless they get hold of the unique key, even if they know the algorithm.
3DES is now used in place of DES became as computers became more powerful, DES became more vulnerable and was cracked by hackers (Castelino, 2006). DES is a block cypher, acting on a fixed-length block of plaintext which it converts into a block of ciphertext of the same size using a secret key. The block size is 64 bits. The key is also 64 bits, and 8 bits are used for parity, making the effective key length 56 bits. In 3DES, 3 stages of DES are applied with a separate key for each for each stage, making the key length a total of 168bits. Decryption involves reverse transformation of the block of ciphertext using the same key. This makes it a symmetric key cipher. The middle portion of the 3DES is a decryption rather than an encryption because it turns the ciphertext back to what it was originally.
A nonce is a randomly generated value used to defeat playback attacks in communication protocols (Nonce, 2006). The first party generates a nonce and sends it to the second party. The second party encrypts it using a secret key that they have agreed upon and returns it to th...