Cryptology ePrint Archive: Report 2021/1667

Using data compression and randomization to build an unconditionally secure short key cipher

Boris Ryabko

Abstract: We consider the problem of constructing an unconditionally secure cipher for the case when the key length is less than the length of the encrypted message. (Unconditional security means that a computationally unbounded adversary cannot obtain information about the encrypted message without the key.) In this article, we propose data compression and randomization techniques combined with entropically-secure encryption. The resulting cipher can be used for encryption in such a way that the key length does not depend on the entropy or the length of the encrypted message; instead, it is determined by the required security level.

Category / Keywords: secret-key cryptography / secret-key cryptography, information theory, entropic security, entropically-secure symmetric encryption scheme, indistinguishability, data compression, Shannon code

Date: received 19 Dec 2021

Contact author: boris at ryabko net

Available format(s): PDF | BibTeX Citation

Version: 20211220:135856 (All versions of this report)

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