Performance Analysis of Stream Cipher RC4 Variants: VMPC & SPRITZ

Abstract

Stream cipher algorithms are most powerful tools in symmetric cryptography. These algorithms perform either bit wise or byte wise encryption in a simple way just doing XOR operation between key and message (plain text). Stream cipher algorithms are about 5 to 10 times faster than AES, TDES (block cipher). In stream cipher, creating key stream by randomizing the bits is most important thing. These algorithms are useful normally in GSM mobile communication, Hard disk encryption, Multimedia encryption and fast Software encryption, standard web application, network protocols etc. In this thesis, stream cipher RC4 variants VMPC & SPRITZ are studied, analyzed the performance and implemented in Java Programming using NetBeans 8.0.2 considering their other parameters constant. The empirical performance shows that VMPC cipher is found to be better if the message size is bigger. With small size of message stream cipher RC4 variants VMPC & SPRITZ shows worst performance. The speed of stream cipher SPRITZ is much slower due to cryptographic function “sponge function”, where different functions are used for the additional layer of security in RC4 variants, although performance of SPRITZ also increases with increment of size of message. While the message size gets increased, performance of stream cipher VMPC is better in all size of messages .Therefore, while inputting different and big size of message, performance of stream cipher VMPC gets increased and it is found to be the better algorithm for the large size message in the targeted architecture computer.