04866769 is referenced by 240 patents and cites 26 patents.

The copy protection of personal computer (PC) software distributed on diskettes is assisted by providing a unique identification (ID) stored in read only memory (ROM) of a personal computer in which software on a diskette is to be used. This ID is accessible to the user of the computer. A vendor who wishes to protect his diskette-distributed software from illegal copying or use provides a source ID on the diskette. The personal computer ID is used with the source ID on the distributed diskette to produce an encoded check word, using any available encryption modality. The check word is generated and written onto the distributed diskette during installation and copied onto all backup versions made by the user's personal computer. Prior to each use of the program, the software on the diskette uses the personal computer and the source IDs and check word to verify that the software is being used on the same personal computer on which it was installed.

Title
Hardware assist for protecting PC software
Application Number
7/82015
Publication Number
4866769
Application Date
August 5, 1987
Publication Date
September 12, 1989
Inventor
Alan H Karp
Palo Alto
CA, US
Agent
Baker Maxham Jester & Meador
Assignee
IBM Corporation
NY, US
IPC
H04L 9/00
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