MICROPROCESSOR FOR EXECUTING ENCIPHERED PROGRAMS

摘要

A microprocessor (16) for executing computer programs (12) which are stored (12) in cipher to prevent software piracy. Such a crypto-microprocessor (16) deciphers (4) the enciphered program (12) piecemeal as it executes it (67), so that a large enciphered program (12) can be securely executed without disclosing the deciphered program or associated data to persons who have access to the wiring of the computer in which the crypto-microprocessor (16) is a component. Various methods of deciphering may be used including methods which result in the cipher of a byte being a complex function of the byte's address in memory. Each crypto-microprocessor chip (16) may use a unique cipher key (5) or tables for deciphering the program (12), so that a program that can be executed in one chip cannot be run in any other microprocessor.