초록 ▼

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, transpo

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.

대표청구항 ▼

A microprocessor apparatus for executing a computer program stored in enciphered form as a plurality of bytes of enciphered information, while protecting the deciphered form of the program, wherein each said byte of enciphered information is identified by a digital address, the apparatus comprising:

A microprocessor apparatus for executing a computer program stored in enciphered form as a plurality of bytes of enciphered information, while protecting the deciphered form of the program, wherein each said byte of enciphered information is identified by a digital address, the apparatus comprising: scrambling means for performing a substitution transformation on the digital address of a byte of said enciphered information, so as to produce a scrambled address: means for deciphering said byte of enciphered information by combining said scrambled address with said byte of enciphered information so as to produce a byte of deciphered information; and processing means for fetching a byte of said deciphered information containing at least a portion of an executable instruction, for executing said executable instruction, and for addressing a successor byte of enciphered information, said processing means being operative to produce output information from which less than a significant part of said program in deciphered form can be obtained.