RC4 Stream Cipher with a Modified Random KSA

Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 298)


The RC4 stream cipher has two components: KSA and PRGA. Though this simple and fast cipher proved itself as robust enough and it is trusted by many organizations, though a number of researchers claimed that RC4 has some weakness and bias in its internal states. Some researchers pointed to the swap function of RC4 as a main reason of weakness, especially in the KSA. The authors replaced the KSA randomly with a robust PRBG, BBS, to fill-up the internal state array, which they named as the KSA-R, to eliminate the swap function from KSA. The original RC4 and the modified RC4 are tested with NIST Statistical Test Suite, and it has been found that RC4 with KSA-R is giving a better security.


Modified RC4 Random RC4 Random KSA Random S-Box Modified KSA 


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Copyright information

© Springer India 2014

Authors and Affiliations

  1. 1.Department of Computer Science and EngineeringUniversity of CalcuttaKolkataIndia
  2. 2.Institute of Radio Physics and ElectronicsUniversity of CalcuttaKolkataIndia

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