DES implemented as a Excel Spreadsheet

I had my first opportunity to meet Jim Hughes at an internal shindig a couple of weeks ago; aside from his being a really great guy – and an expert at washing dishes – it turns out that we have at least one shared co-author (Paul Leyland) and considerable overlap in interests.

Doing a little digging after the event, I encountered the following gem from 2004 and which doesn’t seem to have gotten deserved coverage:

The Illustrated DES Spreadsheet – which Jim himself describes:

Date: Tue, 28 Sep 2004 13:29:29 -0400
From: james hughes
Subject: Illustrated DES Spreadsheet

For anyone wondering, or teaching about DES, or interested in perverse uses for spreadsheets, I have created an “Illustrated DES spreadsheet”. This is a vanilla spreadsheet (no VB or anything exotic) and should work on many excel and excel workalikes.

[www.stortek.com]

Acknowledgements for this work goes to J. Orlin Grabbe for his The DES Algorithm Illustrated which can be found at

[www.aci.net]

I have also stole many tricks including how to do XOR in generic excel which I can not find again to give proper credit. I haven’t run this through the FIPS 140-2 level 1 test suite (but this could easily be certified 🙂

Anyone interested in making one for MD-5?

Enjoy

jim

Comments

One response to “DES implemented as a Excel Spreadsheet”

  1. Dan Houser

    FYI — I did DES in an Excel spreadsheet as well, for a graduate course in my MBA in the Spring of 2000, 16-rounds of CBC DES and some 1.6 million formulas. The REALLY painful part was doing DES by long-hand on paper to validate, which was about 160 hours. Everyone I’ve shown it to called me nuts.

    Unfortunately, it was a few months before I sat for the CISSP, so no CPEs earned!

    ddh

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