Browse Prior Art Database

Method for Verifying Program Authorization by Serial Number and Expiration

IP.com Disclosure Number: IPCOM000113856D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Diedrich, RA: AUTHOR [+2]

Abstract

Described is a method of verifying authorization to use a program based on system serial number, expiration date, and an enablement string.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 63% of the total text.

Method for Verifying Program Authorization by Serial Number and Expiration

      Described is a method of verifying authorization to use a
program based on system serial number, expiration date, and an
enablement string.

      This disclosure describes a collection of related methods to
verify that a program is running on an authorized machine and that an
expiration date has not passed based on a verification string that
can be read over the telephone, sent via fax, or sent via other
electronic means.

      One method to solve this problem is to encode a combination of
the expiration date and a CRC or other hash of the combination of the
expiration date and system serial number.  This technique can be used
at many different levels based on the security required.  Some
examples
of levels and implementations (in order of increasing security) are:
  1.  Expiration date (can be encoded in two bytes) and two byte
      CRC with bits interleaved and/or combined with a function
      such as exclusive or.
  While this is a fairly simple algorithm to implement, it would
  require quite a bit of hacking to reverse engineer.  The result
  is a four byte number which can be read as eight hexadecimal
  characters.
  2.  Expiration date and two or four byte CRC encrypted with
      standard (single key) encryption.
  If DES is used as the encryption mechanism, the result will
  be an eight byte block of data.  This is somewhat more secure,
  p...