wolf@mel.cipl.uiowa.edu (09/14/90)
I know many will or cannot post code for protection schemes (as it would most likely defeat the purpose). I was wondering how large programs are copy protected, I would like to know about two ways....The first is ones which can tell that they have been copied and won't run, and second, ones which cannot be copied (as the data can't be read from disk). I don't mean simple things like setting the locked bit or anything like that, but real ways... Code most appreciated, descriptions or psuedo-code would be dandy also. Thanks! M Wolf
Hooper_TA@cc.curtin.edu.au (Todd Hooper) (09/14/90)
In article <1990Sep13.111657.1@mel.cipl.uiowa.edu>, wolf@mel.cipl.uiowa.edu writes: > I know many will or cannot post code for protection schemes (as it would most > likely defeat the purpose). Well, apart from the standard 'store their name in the data fork' style protection used by Microsoft and others... One I came across recently in an expensive music program asked you to install onto a hard drive. This appeared to copy four invisible files to the top level of your HD. When the program ran, if it couldn't find the files it promptly asked you to reinstall from the master disk or somesuch. Of course, this is a problem if your cheap Taiwanese master disk goes bad all of a sudden and you want to shift the program to another machine (as was the case with the musicians who thought they would be able to move the program back and forth between two Macs). Also, the data files had been screwed around with in some fashion which made them impossible to copy completely. They seemed to contain just junk but it was probably some encoded info about the drive it was on. Another nice application made more annoying due to a brain dead protection scheme. Todd
pepke@gw.scri.fsu.edu (Eric Pepke) (09/14/90)
All copy prevention mechanisms I have seen involve almost breaking the operating system or hardware. Some information is hidden where most people don't look for it. Either an archaic feature of the operating system that nobody uses any more is used, or information is written directly to a hardcoded track of the hard disk in a manner that no application program has any business doing, or something like that. When the operating system or hardware gets changed or updated, most of these systems break. Copy prevention mechanisms have two main effects. First, they annoy users. Second, they provide programmers with fifteen minutes of puzzle-solving fun. Eric Pepke INTERNET: pepke@gw.scri.fsu.edu Supercomputer Computations Research Institute MFENET: pepke@fsu Florida State University SPAN: scri::pepke Tallahassee, FL 32306-4052 BITNET: pepke@fsu Disclaimer: My employers seldom even LISTEN to my opinions. Meta-disclaimer: Any society that needs disclaimers has too many lawyers.
ts@cup.portal.com (Tim W Smith) (09/15/90)
Re: copy protection schemes that put invisible files on the disk. The invisible files probably contain information about which disk blocks are occupied by the application. One way around this sort of protection is to install the thing on a dedicated disk partition. For example, if the program is 500K, make a 600K SUM partition, and install it there. You can now make copies by copying the partition. Tim Smith