Re: Black Eye for NSA, NIST, and Denning

[Phil Karn <karn@qualcomm.com>]

>Gee, now that mab@research.att.com (Matt Blaze), knows where to find
>the checksum, and by extension the unit id (Which shows up on labels
>in photos on the literature from Mykotronx) - providing a known plaintext,
>maybe someone will start working on the family key?

Matt's attack doesn't require knowing where the checksums and unit IDs
are in the LEAF. Nor does it provide any insight into cracking
Skipjack itself, which would be required to learn the family key. He
simply determined that the chip will accept 1 out of every 65,536
randomly chosen LEAFs, which is a large enough fraction to make a
brute force search for one quite practical -- especially since it only
need be done once.

Phil