Abstract: A microprocessor for executing computer programs which are stored in cipher to prevent software piracy. Such a crypto-microprocessor deciphers the enciphered program piecemeal as it executes it, so that a large enciphered program 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 is a component. Such a device may process valuable proprietary programs and data files which are distributed in cipher on videodiscs, semiconductor memory, or other media without risk of software piracy. Various methods of encryption may be used including methods which result in the cipher of a byte being a complicated function of the byte's address in memory. Each crypto-microprocessor chip may use a unique cipher key or tables for deciphering the program, so that a program that can be executed in one chip cannot be run in any other microprocessor.

Abstract: A microprocessor for executing computer programs which have been enciphered during manufacture to deter the execution of the programs in unauthorized computers. This microprocessor deciphers and executes an enciphered program one instruction at a time, through a combination of substitutions, transpositions, and exclusive-OR additions, in which the address of each instruction is combined with the instruction. Each unit may use a unique set of substitutions so that a program that can be executed in one microprocessor can not be run in any other microprocessor.