Pynchon gate
PIR seminal paper:
Private Information Retrieval (PS) (Cached: PS, gzipped PS) by Benny Chor, Oded Goldreich, Eyal Kushilevitz, and Madhu Sudan. In the Proceedings of the IEEE Symposium on Foundations of Computer Science, 1995, pages 41-50 http://freehaven.net/anonbib/cache/pir.ps.gz
The Pynchon-gate, pseudonymous email system, using PIR; introduction & protocol description:
http://freehaven.net/anonbib/cache/sassaman:wpes2005.pdf
protocol specification : http://freehaven.net/pynchon/doc/pynchon-spec.txt
Fred Wulff: Analyzing the Pynchon Gate Protocol (March 21, 2008): http://www.stanford.edu/class/cs259/WWW08/projects/cs259-final-Fred/cs259final.pdf more material & papers: http://www.abditum.com/pynchon/
len's 24c3 talk (anonymizing networks, pynchon gate overview):