Product block cipher system for data security
Key register controlled accessing system
Computer software security system
Microprocessor for executing enciphered programs Patent #: 4168396
ApplicationNo. 05/942422 filed on 09/14/1978
US Classes:712/208, INSTRUCTION DECODING (E.G., BY MICROINSTRUCTION, START ADDRESS GENERATOR, HARDWIRED)714/699PULSE OR DATA ERROR HANDLING
ExaminersPrimary: Atkinson, Charles E.
Attorney, Agent or Firm
International ClassesG06F 9/318 (20060101)
G06F 9/30 (20060101)
G06F 21/00 (20060101)
AbstractA method for controlling usage of a programmable computing machine which operates in accordance with uncoded or published machine language operation codes including uniquely encoding the uncoded operation codes of instructions of a program to be used on the computing machine as a function of location of the instructions in memory and as a function of machine state, and adding to the machine a decoder that decodes only the uniquely encoded operation codes. Apparatus for controlling usage of a programmable computing machine which operates in response to uncoded or published machine language operation codes including memories which store machine user created programs and operating system programs, in which each program has instructions with uncoded and encoded operation codes, decoders to decode the encoded operation codes of the instructions of the user created program and the encoded operation codes of the instructions of the operating system program, and a circuit to execute the instructions of the user created program and the operating system program having the decoded and the uncoded operation codes.