PROGRAM SECURITY DEVICE

• US 3,609,697 A
• Filed: 10/21/1968
• Issued: 09/28/1971
• Est. Priority Date: 10/21/1968
• Status: Expired due to Term

• Current Assignee: David W. Terry, Parker R. Blevins, Ray H. Thurmond
• Original Assignee: David W. Terry, Parker R. Blevins, Ray H. Thurmond
• Inventors: Blevins, Parker R., Thurmond, Ray H., Terry, David W.
• Primary Examiner(s): Henon, Paul J.
• Assistant Examiner(s): Springborn, Harvey E.
• Application Number:
  US04/769,149
• Time in Patent Office: 1,072 Days
• Field of Search: 340/146.1,172.5 235/157
• US Class Current: 717/106
• CPC Class Codes: G06F 21/101 by binding digital rights to specific entities
• CPC Class Codes: G06F 21/123 by using dedicated hardware, e.g. dongles, smart cards, cryptographic processors, global positioning systems [GPS] devices

Abstract

A program security device and method for a digital computer including a code generating circuit for providing a unique and predetermined output code to the digital computer for periodic comparison with identification information located within the stored program of the computer. If the identification information does not coincide with the output code, a jump operation is performed and certain portions of the stored program are changed in order to prevent the execution of the program. The output code can be utilized as a mask source for the program and/or a regenerative program routine can be utilized in order to prevent simple evasion of the routine.

Claims

1. A method for insuring that a sequencE of stored program instructions are performed only by a data processing system having a code generating device which generates a programmably unalterable, unique, predefined code comprising the steps of:

controlling said data processing system by initiating the performance of said sequence of stored program instructions, said stored program instructions including a predetermined instruction;

generating said unique predefined code by said code generating device in response to said predetermined instruction, said predetermined instruction further defining stored information corresponding to the unique predefined code;

comparing the generated code with said defined stored information;

changing the information content of subsequent instructions in said sequence of stored instructions so as to render said subsequent instructions of stored program inoperable if the compared generated code differs from the compared defined stored information.

2. A programmable data processor comprising:

storage means for storing character representations including characters representative of a sequence of data processing instructions;

storage addressing means for normally accessing said sequence of data processing instructions in a predetermined ordered program sequence including means for alternatively accessing a nonsequential instruction defined by an accessed conditional branch instruction in response to a control signal;

an actuable code generator responsive to a predefined data processing instruction accessed from said storage means for providing a fixed, constant and programmably unalterable character output signal;

actuable compare means responsive to said accessed predefined data processing instruction and to the output signal of the code generator for providing an output noncompare signal whenever said character output signal fails to correspond to a predetermined stored character representation defined by said accessed predefined data processing instruction;

control means responsive to said output noncompare signal and to a conditional branch instruction accessed subsequent to the accesses of said predefined instruction for providing said control signal;

bit generator means responsive to said accessed consequential instruction for changing stored character representations representative of subsequent instructions in said sequence of instructions in said storage means.