METHOD FOR BLOCKING SMART CARD

PCT No. PCT/FR92/00407 Sec. 371 Date Mar. 28, 1994 Sec. 102(e) Date Mar. 28, 1994 PCT Filed May 5, 1992 PCT Pub. No. WO92/20042 PCT Pub. Date Nov. 12, 1992.A method of locking a smart card to block the operation of at least one protected program stored in a read-only memory or ROM of the smart card, the smart card incorporating a central processor, the ROM, an erasable programmable read-only memory or EPROM and a random access memory or RAM, the method including the steps of: entering a logic lock in the EPROM, making multiple copies of the logic lock in the EPROM, carrying out a logic OR on the logic lock in the EPROM and the multiple copies of the logic lock in the EPROM in order to block the performance of the protected program upon the detection of either (a) the logic lock in the EPROM or (b) at least one of the multiple copies of the logic lock in the EPROM, recopying the logic lock in the RAM, and performing the logic OR on the logic lock in the EPROM, the multiple copies of the logic lock in the EPROM, and the logic lock in the RAM.