In this paper, we attempt at proving the new, unproved or partially proved biases amongst the above-mentioned ones. The theoretical proofs of these biases not only assert a scientific justification, but also discover intricate patterns and operations of the cipher associated with these biases. For example, while attempting the proof of a bias of the first output byte towards 129, we observe that this bias occurs prominently only for certain lengths of the secret key of RC4. In addition, our findings reveal that this bias may be related to the old and unsolved problem of ``anomalies'' in the distribution of the state array after the Key Scheduling Algorithm. In this connection, we prove the anomaly in $S_0 = 127$, a problem open for more than a decade.
Other than proving the new biases, we also complete the proof for the extended keylength dependent biases in RC4, a problem attempted and partially solved by Isobe, Ohigashi, Watanabe and Morii in FSE 2013. Our new proofs and observations in this paper, along with the connection to the older results, provide a comprehensive view on the state-of-the-art literature in RC4 cryptanalysis.Category / Keywords: secret-key cryptography / Stream cipher, RC4, Biases, Short-term, Keylength dependent, Anomaly Date: received 15 Aug 2013 Contact author: sg sourav at gmail com Available format(s): PDF | BibTeX Citation Version: 20130815:072909 (All versions of this report) Short URL: ia.cr/2013/502 Discussion forum: Show discussion | Start new discussion