The Sizlak Curve

[John Young]

A NSA FOIA processing file cites "The Sizlak Curve" as a source 
searched  by the Cryptography Office for documents related to
the British Non-Secret Encryption, precursor to publc key
cryptography.

Information on what "The Sizlak Curve" means is welcomed.
NSA says the term is unclassified.  It could be disinfo or a joke.

An image of the citation:


http://cryptome.org/sislak-curve.jpg

The processing file from which the image is taken:


http://cryptome.org/nsa-nse-061208.zip (142pp, 4MB)

Forwarding this inquiry to crypto lists and fora would be
appreciated.