SYSTEM FOR PREVENTING SOFTWARE PIRACY EMPLOYING MULTI- ENCRYPTED KEYS AND SINGLE DECRYPTION CIRCUIT MODULES

摘要

17-ABSTRACT OF THE DISCLOSUREA system (FIG. 1) which enables a protectedprogram (e.g., prog. A, prog. B., ...) to run only aselected plurality of computers (e.g., computer 10)including a respective unique key Ki for each computer ofthe plurality, the key being triple encrypted (14a) in theform EFK[EFK[Ki]]]. A respective module (16) is coupled(via 17) to each computer (10) of the plurality. Achecker program (15) in each computer responds to arequest (from station 11) to use the protected program byperforming a single decryption procedure E?? on the tripleencrypted key (step 22 of FIG. 2) and sends the result(step 23) to the module (16) as a message. The module(16) performs a single decryption procedure E?? on themessage (step 25) and sends that result (step 26) back tothe computer. The checker program (15) receives themodule's result and performs another single decryptionprocedure E?? on it (step 28) to obtain key Ki. Then thechecker program (15) uses key Ki to decrypt an identifier,(e.g., 14b, 14c, ...) and proceeds with the execution ofthe protected program only if it is identified by thedecrypted identifier (step 32).