A New Technique for Sub-Key Generation in Block Ciphers
Jamal N. Bani Salameh · 2012
Abstract: In symmetric cryptosystems a primary key is used to create a number of subkeys according to specified key scheduling algorithm; the design of a good key schedule is a crucial aspect of cipher design. In this paper we describe a new technique to generate pseudorandom subkeys to be used in cryptographic algorithm suitable for hardware or software implementations; a simple and secure method for subkey selection is presented based on the use of permutation up to the bit-level of the main key. The proposed technique has higher resistance against brute-force attack, differential cryptanalysis and linear cryptanalysis. Furthermore, it will extend the lifetime of the master key by using the idea of re-keying and it will increase the security of the encryption algorithm. Simulation study shows that the proposed technique gives a totally different group of pseudorandom subkeys each time we run the generator. Furthermore; comparison analyses between the proposed subkey generation process and the old technique used in MJEA shows that this scheme provides better performance concerning the Avalanche Effect criteria. The design principle of the new method is given together with results and analyses to define the whole process precisely.