Cryptology ePrint Archive: Report 2002/149

About Filliol's Observations on DES, AES and Hash Functions (draft)

Nicolas T. Courtois

Abstract: Recently Filiol proposed to test cryptographic algorithms by making statistics on the number of low degree terms in the boolean functions. The paper has been published on eprint on 23th of July 2002. In this paper we reproduce some of Filiol's simulations. We did not confirm his results: our results suggest that DES, AES, and major hash functions have no significative bias and their output bits behave just like random boolean functions.

Category / Keywords: secret-key cryptography / block ciphers, DES, AES, hash functions, SHA-1, Haval, RIPEMD, MD4, MD5, boolean functions

Publication Info: draft, will probably never be published

Date: received 1 Oct 2002, last revised 2 Oct 2002

Contact author: courtois at minrank org

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Note: Few hours after the submission of this paper, Filiol updated his paper. His new, updated results show that, there is indeed no bias in the terms of degree <=2 in DES or AES. Thus Filiol confirmed our results. However he still does claim some other biases in DES and AES for different, more complex tests. Who knows...

Version: 20021002:142142 (All versions of this report)

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