Publication

Abstract : Encryption algorithms such as Advanced Encryption Standard (AES) are known as symmetric encryption algorithms which use the same key for both encryption and decryption. These algorithms have a huge variety of applications such as for securing data and transferring files. They also have a key expansion algorithm which is used for expanding the given key. In AES the key expansion algorithm expands the given 128 bit key into 176 bytes which will then be used in the encryption process which spans for 10 rounds. This paper aims at making this process even more secure. This is implemented by including different steps to increase security in this key expansion process so that it becomes computationally infeasible to get the original key even if the adversary gets a hold of the different parts of the key. Current works suggest that there is a need for increased security in the key scheduling algorithm of the AES. It has also been tested to have inferior strict avalanche criteria in comparison with other contenders of the AES such as Serpent and Twofish. Usage of the concept of affine recurrence ensures this in the proposed model. In affine recurrence, no two outputs of the operation will have a relation between them. Another concept used is the AES Substitution Box (S-box), and this is done to ensure higher levels of confusion in the key scheduling process.