Kimio Kuramitsu Tadashi Murakami Hajime Matsuda Ken Sakamura TTP: Secure ACID Transfer Protocol for Electronic Ticket between Personal Tamper-Proof Devices . 87-92 2000 conf/compsac/2000 COMPSAC http://computer.org/proceedings/compsac/0792/07920087abs.htm db/conf/compsac/compsac2000.html#KuramitsuMMS00