Paper 2015/1043

The Index j in RC4 is not Pseudo-random due to Non-existence of Finney Cycle

Subhamoy Maitra

Abstract

In this very short note we prove that the pseudo-random index j of RC4 is indeed not pseudo-random. This is a simple result that missed our attention for quite a long time. We show that in long term Pr(j = i+1) = 1/N - 1/N^2, instead of the random association 1/N and this happens for the non-existence of the condition S[i] = 1 and j = i+1 that is mandatory for the non-existence of the Finney cycle.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Preprint. MINOR revision.
Keywords
RC4Non-randomnessPseudo-random Index.
Contact author(s)
subho @ isical ac in
History
2015-10-28: received
Short URL
https://ia.cr/2015/1043
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2015/1043,
      author = {Subhamoy Maitra},
      title = {The Index j in RC4 is not Pseudo-random due to Non-existence of Finney Cycle},
      howpublished = {Cryptology ePrint Archive, Paper 2015/1043},
      year = {2015},
      note = {\url{https://eprint.iacr.org/2015/1043}},
      url = {https://eprint.iacr.org/2015/1043}
}
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