Cryptology ePrint Archive: Report 2017/589

An Attempt to Cryptanalyze A Partially Known Cipher Algorithm

Juay Guan Hee

Abstract: This paper presents an empirical crypt-analytical method to analyse a partially known cipher algorithm. During cipher evaluation, it is always a challenge to make any decision on the strength of a partially known cipher algorithm, and if the algorithm is suitable for deployment. The core concept will be presented first, followed by an example to illustrate the idea. The idea is to focus on one input bit at a time using a known keystream attack, assuming this bit is independent from the rest. By computing the statistics of related keystream bits and using the correlation method, one can derive this input bit with certain confidence.

Category / Keywords: secret-key cryptography / Linear Feedback Shift Register, Correlation Coefficient, Stream Cipher.

Date: received 17 Jun 2017

Contact author: hjuaygua at gmail com

Available format(s): PDF | BibTeX Citation

Note: Please note that this is NOT a randomness test. This is a proven concept tested using simulation, as well as using double blind method. With this method, one can analyze a particular type of cipher with the linear complexity instead of exponential complexity.

Version: 20170620:154008 (All versions of this report)

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