Cryptology ePrint Archive: Report 2003/003

Plaintext-dependant Repetition Codes Cryptanalysis of Block Ciphers - The AES Case


Abstract: This paper presents a new ``operational'' cryptanalysis of block ciphers based on the use of a well-known error-correcting code: the repetition codes. We demonstrate how to describe a block cipher with such a code before explaining how to design a new ciphertext only cryptanalysis of these cryptosystems on the assumption that plaintext belongs to a particular class. This new cryptanalysis may succeed for any block cipher and thus is likely to question the security of those cryptosystems for encryption. We then apply this cryptanalysis to the 128-bit key AES. Our results have been experimentallly confirmed with 100 {\bf effective} cryptanalysis. Our attack enables to recover two information bits of the secret key with only $2^{31}$ ciphertext blocks and a complexity of $\mathcal{O}(2^{31})$ with a success probability of 0.68.

Category / Keywords: secret-key cryptography / AES, block ciphers, cryptanalysis, coding theory, repetition codes

Date: received 14 Jan 2003, last revised 23 Jan 2003

Contact author: efiliol at wanadoo fr

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

Note: In order to not saturate the eprint server (thanks to the editors for their patience and kindness) with frequent updates of this paper, all will be progressively available on the author's webpage ( on and after the January 31st (random generator sources, data, new equations,...).

Version: 20030123:183530 (All versions of this report)

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