OpenEuphoria

Encoding for Trapped Mods

• Posted by "C. K. Lester" <cklester at TICNET.COM> Oct 12, 1999
• 476 views

Here's what I wanna do:

   Create a simple txt file with one line
   of text + numbers, i.e., HD85739DJA9273JKS,
   which is hiding a license code.

   Protect the file so that if a change is
   made to it, a checksum will fail and I'll
   know that tampering has been tried.

Anybody have good ideas in this regard?

I'm thinking along the lines of the following:

   1. Convert the license code (say '109') to hex.
   2. Add the ASCII codes of the digits (6D)
      for a checksum item.
   3. Create the line of text: 6DXGLP122, where
      6D is the hex of 109, and 122 is the checksum,
      both of which are separated by a non-hex
      character sequence of letters (XGLP).

So basically, I would parse out the 6D and the 122
and make sure they match. Would I also want to
checksum the separater text, as well? That's a thought.

Anyway, any and all ideas appreciated!

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