"An efficient Scheme for Proving a Shuffle", Crypto 2001, Jun Furukawa and Kazue Sako (NEC Corporation), apparently could be used to show that a remailer is processing all messages without revealing the header or contents of any message. (Apparently because I haven't read the paper -- just heard of it on the nymip-res-group list.) =============================================== Mark Leighton Fisher fisherm@tce.com Thomson multimedia, Inc. Indianapolis IN "Display some adaptability." -- Doug Shaftoe, _Cryptonomicon_