Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!udel!rochester!kodak!ispd-newsserver!ism.isc.com!ico!rcd
From: rcd@ico.isc.com (Dick Dunn)
Newsgroups: comp.lang.postscript
Subject: Re: Protecting one's code.
Summary: difficult
Message-ID: <1991Apr3.235649.29350@ico.isc.com>
Date: 3 Apr 91 23:56:49 GMT
References: <1991Apr3.174645.15251@ttank.ttank.com>
Organization: Interactive Systems Corporation, Boulder, CO
Lines: 30

tts@ttank.ttank.com (Karl Bunch) writes:
> ...Now that we are starting to create all kinds of PostScript forms
> logos etc. we are concerned about the basic "Source" form that we must
> give to the customers.  So as to avoid priracy is there a way we can use
> eexec or some such to encode the PostScript source?  It doesn't have to
> be fullproof.  Just something that would stop the average PostScript
> programmer because of the "Complexity" of having to decode it etc etc.

Well, start with a correct copyright notice, of course!

Since the definition of the PostScript language is easily available, and
since there is freely-redistributed code for PostScript interpreters,
you're definitely in a "Locks are for honest people" situation.

eexec probably fits what you want.  It's an obstacle to a duffer; it's a
mild annoyance to someone who knows PostScript.  The real point is that it
sufficiently obscures the code that nobody can "just happen to" read code
that's been eexec-encrypted, nor "accidentally" decrypt it.  You can add to
that a process to "shroud" the code before encryption--things like com-
pressing out all unnecessary white space and using the shortest possible
names for objects.  You probably want to do that anyway just to minimize
the size of the file you send to the printer.  Neither of these do any-
thing about verbatim copying; they just slow down the process of making
it understandable.

Other than that, the best way to protect a product is to move faster than
the folks who think "xyzzy-compatible" means "copy it and sell it."
-- 
Dick Dunn     rcd@ico.isc.com -or- ico!rcd       Boulder, CO   (303)449-2870
   ...Lately it occurs to me what a long, strange trip it's been.