公开(公告)号：US3461430A

公开(公告)日：1969-08-12

申请号：US3461430D

申请日：1966-09-14

Applicant: IBM

Inventor： BLEVINS PARKER R ,  HEARD RODERICK S ,  HORNUNG LOUIS M

IPC: G11B15/00 ,  G11B15/18 ,  G11B20/16 ,  G11B5/02 ,  G06F7/00 ,  G06K7/016 ,  G08B29/00 ,  G08C ,  G08C25/00

CPC classification number: G11B20/16 ,  G11B15/005 ,  G11B15/1808

公开(公告)号：US3609697A

公开(公告)日：1971-09-28

申请号：US3609697D

申请日：1968-10-21

Applicant: IBM

Inventor： BLEVINS PARKER R ,  TERRY DAVID W ,  THURMOND RAY H

IPC: G06F21/00 ,  G06F11/04

CPC classification number: G06F21/123 ,  G06F2221/0744

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.