**The Disparity between Work and Entropy in Cryptology**

*John Pliam*

**Abstract: **A brief theory of work is developed. In it, the work-factor and
guesswork of a random variable are linked to intuitive notions of time
complexity in a brute-force attack. Bounds are given for a specific
work-factor called the minimum majority. Tight bounds are given for
the guesswork in terms of variation distance. Differences between
work-factor, guesswork and the entropy of a random variable are
pointed out, calling into question a common misconception about
entropy indicating work.

**Category / Keywords: **Entropy, Information Theory, Brute-Force Attack, Work Factor, Guessing Entropy.

**Publication Info: **Appeared in the THEORY OF CRYPTOGRAPHY LIBRARY and has been included in the ePrint Archive.

**Date: **received November 9th, 1998. Revised, February 1st, 1999.

**Contact author: **pliam at ima umn edu

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

**Short URL: **ia.cr/1998/024

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