RC4 is the most widely used stream cipher around. So, it is important that it runs cost effectively, with minimum encryption time. In other words, it should give higher throughput. In this paper, a mechanism is proposed to improve the throughput of RC4 algorithm in multicore processors using multithreading. The proposed mechanism does not parallelize RC4, instead it introduces a way that multithreading can be used in encryption when the input is in the form of a text file. In this particular research, the source codes were written in Java (version: 1. 6. 0_21) in Windows environments. Experiments to analyze the throughput were done separately in an Intel P4 machine (O/S: Windows XP), Core 2 Duo machine (O/S: Windows XP) and Core i3 machine (O/S: Windows 7). The main objective of the research was to study the robustness of RC4 (implemented purely in software) when encryption is done in multiple threads. In other words the intension was to improve the throughput of RC4 by using parallelism. For that, the following mechanism was used: Chunking the input text file into similar sized portions, then encrypting each portion by RC4 (key size: 128 bits) and merging all encrypted portions together then finally saving the final encrypted file in a folder. This process was done multiple threads to get the advantages of eligible parallelism in multicores. (using Executors in Java). Measurement criteria: Execution time (i. e. time taken to chunk, encrypt and form the final encrypted files by merging all the portions) of different data sizes in different types of multicores when using the sequential approach and parallel approach. The outcome: Higher throughput of RC4 can be achieved in multicores when using the described mechanism in this research. Effective use of multithreading in encryption can be achieved in multicores.

Throughput of RC4 Multithreading in Encryption