On computer face recognition:

[Jonathan Litt]

  geeman at best.com writes:
   > Subject: Re: On computer face recognition:
   > Date: Thu, 11 Apr 1996 23:30:49 -0700
   >
   > There was a piece, I _think_ in Scientific American, tho it might
   > have been an AI journal, on face recognition by use of neural
   > nets together with what were called "eigenface" images: These
   > eigenfaces each have specific characteristics, which when
   > combined together can closely approximate a specific face image.
   > The target face was analyzed in terms of closeness-of-match to a
   > small set of eigenfaces, on the order of 5 to 8, I think.
   > Results of course were promising (else why write about it, eh?)
   > if not excellent.

You are thinking of the article in Scientific American about the
Vision and Modeling group at the MIT Media Lab. For face recognition
stuff, check out:

http://www-white.media.mit.edu/vismod/demos/facerec/index.html

Crypto and privacy relevance? Lots, I imagine.

-jon