FIELD: payment systems using smart cards. SUBSTANCE: system-level central checkup of protection includes technology of statistical samples in conjunction with effective tracing of electronic coin operation path to its source. Only small number of storage and transfer data is used in system thereby making it possible to dispense with large centralized data banks including operation records. System ensures anonymity of clients and flexible card-to-card transfer of money at the same time checking protection of entire system and ensuring fast detection and follow-up of protection failure. Several issues of coins enable inconspicuous updating of system and recovery of initial condition of protection and also make it possible to submit regular claims to clients concerning lost or abandoned money. EFFECT: enhanced effectiveness of protection checkup dispensing with complete centralized accounting of each operation. 24 cl, 49 dwg
