The ESPRIT Project CAFE - High Security Digital Payment Systems. - Jean-Paul Boly; Antoon Bosselaers; Ronald Cramer; Rolf Michelsen; Stig Fr. Mjølsnes; Frank Muller; Torben P. Pedersen; Birgit Pfitzmann; Peter de Rooij; Berry Schoenmakers; Matthias Schunter; Luc Vallée; et al. (ESORICS, 1994)