Implementation of AES-128 Using Multiple Cipher Keys

The growth in communication technology has connected billions of people all over the globe. The frequent sharing of data among individuals, organizations and even countries has raised concerns over the security and privacy of the communication process. A successful solution to this problem is Encryption, which converts the data to an unintelligible form. The keys for encrypting and decrypting the data are known only to authorised users. Thus, encryption can efficiently secure the communication process. The technique presented here is a modified form of Advanced Encryption Standard (AES) with multiple cipher keys of length 128 bits. AES uses symmetric cryptography which means that same keys are used for encryption and decryption. AES is known to be resistant against any known cryptanalytic attacks. Although it is known to be secure, various improvements have been suggested previously to further enhance the security of AES. The proposed technique enhances the security by using three cipher keys. By increasing the no. of keys, the encryption and decryption times are increased. Trading off with the increase in encryption time, advantage is gained because the attempt to hack the data will require drastic efforts and thus security is increased.