Shareware Time Lock

 BBS: Inland Empire Archive
Date: 03-18-92 (00:00)             Number: 149
From: SEAN EMBRY                   Refer#: NONE
  To: RICHARD VANNOY                Recvd: NO  
Subj: Shareware Time Lock            Conf: (2) Quik_Bas

Richard,
        I'm developing a time lock that would require a low level format
        to reset with out a key. I would like to make it usable for
        several programs, however, there are only 5 bytes to play with
        in this mannor. I was thinking of using those five bytes to
        point to a cluster, which would be marked bad, and keep the date
        data encrypted there. (see below). The problem is coordnating
        this so that programs don't start colliding with each other.
        Your thoughts?



        I've found the following to be effective in confounding
        hackers for encryption: (IE, it lasted 2 years)

        Junk=BTS*CRC*17
        where Junk is the number of bytes that are not significant
              BTS is the number of bytes needed to store your info
              CRC is a low bit CRC of the info bytes
              Note: if less than 128, use 128
                    direct the program to move the valid data around
                    each time info is updated, and change some of the
                    junk bytes. Always check the CRC, if invalid, erase
                    your program and completely randomize the encryption
                    data file, execpt for a pointer to tell your
                    programs that it has been randomized. (Never
                    touch data, it doesn't belong to you)

        In my programs, BTS numbers 4 to 8 bytes.

        And talking about time keys, a TSR just warned me that I'm using
        OLXTD past it's free time. Time to Register this puppy!
        (Just when I thought I'd have some money to go play with!)

Sean

___
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