[cryptography] DES history

Marcus Brinkmann marcus.brinkmann at ruhr-uni-bochum.de
Mon May 5 16:50:33 EDT 2014


On 05/05/2014 10:37 PM, Marcus Brinkmann wrote:
> On 05/05/2014 09:08 PM, Givon Zirkind wrote:
>> A question about DES.  Did anyone ever try & map or graph the routes
>> through the S-boxes?  I mean pictorially.  Do the routes produce some
>> kind of wave or path, that have (or have not) relationships with the
>> other routes?

[...]

> I don't know (but also haven't checked) of any low-degree (quadratic,
> cubic) versions of the linear (or affine) analysis mentioned.

Replying to myself, a quick google search turns up a quadratic analysis:

Natalia N. Tokareva, "k-Bent functions and quadratic cryptanalysis of 
block ciphers"

http://mc3.i3s.unice.fr/seminaires/seminaires_mc3/2007_2008/08-08-08_tokareva.pdf

"Page 42: "We test permutations with the most high nonlinearity
NL = 4 recommended for using in S-boxes of GOST 28147-89, DES,
s3DES and found that for all of them (excepting one) our crypt-analysis 
gives quadratic relations with probability 7/8 whereas any linear 
equality has probability not more then 3/4."

Well, in any case, glancing over that paper may give you an idea what is 
involved today in such analysis: They are definitely not done visually, 
but involve a lot of higher algebra.  It's not 1976 anymore :)

Thanks,
Marcus



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