We've put the NSA report, "How To Make A Mint: The Cryptography of Anonymous Electronic Cash, June, 1996" at: http://jya.com/nsamint.htm (84 kb) It argues the dangers of anonymous cash and how to combat it. Thanks to the authors, Laurie Law, Susan Sabett and Jerry Solinas, NSA; Thomas Vartanian, Fried, Frank; and anonymous others.