Practical Polynomial Time Known Plaintext Attacks on a Stream Cipher Proposed by John Nash

In this paper, the authors present two known plaintext attacks on a stream cipher which was developed by John Nash in the early 1950's but whose design was declassified by the NSA only in 2012. This attack succeeds with high probability for randomly chosen keys even when the only thing they know about the plaintext is that a small fraction of isolated plaintext bits are slightly biased, but always fails for a certain well defined class of keys which is exponentially large but a negligibly small fraction of all the possible keys.

Provided by: weixun lin Topic: Security Date Added: Nov 2012 Format: PDF

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