Prevent diskcopy and file copying

[Steve Pierce]

I use PBDos 3.5. Can anyone suggest/offer a way in PBDos
language to prevent the function of dos diskcopy and to prevent
the copying of individual files from a diskette.
Please keep it simple code-wise, but I really would like
some help on this. Much Thanks

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[Michael Torrie]

Are you talking about copy-protection, as in old-style lotus 1-2-3 copy protection? (Or Broderbund, being one of the worst offenders -- praise the day copyiipc came out).

You won't find a good method to prevent the actual copying. Many people are under the mistaken impression that the CSS and other schemes are for copy protection. They are actually copyright protection schemes. Every one that tries to limit a user's ability to make backups, etc (infringed on fair use) has failed.

Copyright protection is an important issue. If your worried about data being copied, you may want to use encryption on the data. That way copying doesn't matter, because it's not readable to someone who's not supposed to have it.

To protect copyrights on a program, you might use a licensing scheme whereby a license file contains vital info about a user and a special one-way hash code that can be verified by the program. If the license file is invalid or faked, the computed hash of the license won't match the hash in the license and thus the program can refuse to run. This could be broken, but then all schemes are broken. This method, in my opinion, gives the end user the most freedom to use the program he legitimately has purchased, while preventing mass piracy. If it's popular, though, someone will donate their license to the "cause".

All schemes have weaknesses. The ones that are least convenient for the customer, even if they are strong, will die

I don't know if I'm even close to what you're talking about. If not, just ignore me... To answer one question sepcifically, if you wanted to control the copying of specific files, you could hack dos and write a tsr to intercept the calls. (Scary -- this sounds a lot like Microsoft's "secure computing" concept. Rights enforcement (even if it violates your rights) in the OS)


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