Grosul, AlexanderWallach, Dan S.2017-08-022017-08-022000-06-08Grosul, Alexander and Wallach, Dan S.. "A Related-Key Cryptanalysis of RC4." (2000) https://hdl.handle.net/1911/96275.https://hdl.handle.net/1911/96275In this paper we present analysis of the RC4 stream cipher and show that for each 2048-bit key there exists a family of related keys, differing in one of the byte positions. The keystreams generated by RC4 for a key and its related keys are substantially similar in the initial hundred bytes before diverging. RC4 is most commonly used with a 128-bit key repeated 16 times;this variant does not suffer from the weaknesses we describe. We recommend that applications of RC4 with keys longer than 128 bits (and particularly those using the full 2048-bit keys) discard the initial 256 bytes of the keystream output.13 ppengYou are granted permission for the noncommercial reproduction, distribution, display, and performance of this technical report in any format, but this permission is only for a period of forty-five (45) days from the most recent time that you verified that this technical report is still available from the Computer Science Department of Rice University under terms that include this permission. All other rights are reserved by the author(s).Technical reportTR00-358