SMS4 CIPHER AS A SPREADSHEET

(Originally published 2/24/2009 here)

Building a reference implementation of a cipher  can be an invaluable aid to writing code. Building a cipher in a spreadsheet, while some may suggest is strange, is a valid way to effectively describe a cipher in a visual sense. This has been done before with The Illustrated DES Spreadsheet, it has been done again. With the help of a Chinese document and an english translation by Whitfield Diffie and George Ledin, I was able to create a spreadsheet that demonstrates the SMS4 algorithm. 

This algorithm is rather infamous for being proposed as a WiFi standard. It has raised it’s head again as being implemented inside a derivative of the TCG standard TPM module for China under the name TCM module. 

The SMS4 spreadsheet is available in Mac OS X numbers format and .xls format.

Enjoy...