Re: Is this snake-oil?

[John R Levine <johnl@iecc.com>]

Visit http://patent.womplex.ibm.com/ and learn all about it.  I don't 
claim to know much about cryptography, but these sure look like garbage 
to me.

> 5,307,412, "Random Coding Cipher System and Method"
> 5,335,280, "Random Sum Cipher System and Method"

Sender and receiver share what should be a one-time pad, with a trailer on
each encrypted each message saying where in the pad to start next time.  I
don't see any advantage compared to the standard approach of using your pad
sequentially other than that this scheme makes it harder to tell when it's
used up. 

> 5,533,128, "Pseudo-Random Transposition Cipher System and Method"

Sender and receiver initialize their set of pseudo-random number generators
to the same secret thing and use the generated streams of digits to control a
transposition cipher.  Sheesh. 

I didn't look at the full patents, just the summaries, so I may have missed
something.  Please look at the patents themselves before flaming.  

The IBM web site is a fabulous resource -- they have a CD-ROM farm that
provides scanned page images of all the patents issued for the past several
decades.  Also check out the gallery of obscure patents, e.g., the human
slingshot, and the microprocessor controlled belching beer mug. 

Regards,
John Levine, johnl@iecc.com, Village Trustee, Trumansburg NY
Primary Perpetrator of "The Internet for Dummies" and
Information Superhighwayman wanna-be, http://iecc.com/johnl