sehari@iastate.edu (Babak Sehari) writes:  >In <1993Apr20.230749.12821@reed.edu> mblock@reed.edu (Matt Block) writes:  >>In article <sehari.735331566@marge.ecss.iastate.edu> sehari@iastate.edu (Babak Sehari) writes: >>>--- >>> >>>I was wondering, what copy protection techniques are avaliable, and how >>>effective are they?  Has anyone have any experience in this area? >>> >>>                      With highest regards, >>>                           Babak   Sehari.  >>	Uh oh... >>	Umm, there are a number of copy protection schemes.  Some involve >>modifying the physical media, and some involve encryption schemes, &c. >>	All of the ones that have existed over the course of computing have >>been successful for a time.  I recall, however, near monthly releases of new >>ways to "crack" the copy protection scheme of the latest releases.  The fact >>is, none of them are completely secure, or anywhere near it.  Some are more or >>less difficult to crack, and some have already been cracked. >>	I guess what I am saying is that your question is difficult, if not >>impossible, to answer.  What exactly do you want to know?  Do you need a good >>one for a project you are working on?  How secure must it be?  Are you trying >>to crack one that someone else has used?  I can probably make suggestions, >>assuming the activity is strictly legal.  (In general, it is a BAD idea, >>legally, to tamper with copy protection.  It can also lead to corruption of >>files which you necessarily do not have back ups of (being as they are copy >>protected,) which can be devestating.)  Do you have absolutely no ideas for >>practical applications, and are merely curious? >>	Please clear up those questions, and I'll try to help as much as I >>can.  >>	Incidentally, the "Uh oh..." at the top is indicative of the dread >>anyone who has watched their friends hacking equipment be carted off feels >>when they are asked how to hack.  The area you are broaching is wrought with >>dangers, many of which include breaking the law, or at least addressing it >>(from one side or the other.)  >>Matt  >I have written a program and I want to market it.  I would like certain degree >of protection, since my main custmers are individuals and not the  >cooperations.   I know laser hole burning method, and hardware key method, >however, my  software is going to cost only $15.00, so I can not afford that. >Also, at this low price I can not afford people make too many copy of my >software. Well, I guess say upto %20 illigal copying is ok by me.  >However, I do not want someone to get a copy of PCTools and copy my software.   >Off course, I never meant to forbid the true hackers from copying, since they >can develope a better program anyway.  >                      With highest regards, >                           Babak   Sehari.   >--   One of the most popular methods of course is the password check where they ask you for a word from page x, line y, and word z, but this is pitifully simple to remove unless you throw some checksums into the main part of your program, and some self-rewriting code to confuse some people.  Also, make sure that your program can not be run out a debugger.  Another method of course is to not even make bad sectors on the original disk, just write a certain key to a certain unallocated sector.   To help you here, you also must do the code protection schemes mentioned in the first paragraph. Make sure you also fill the rest of the unallocated parts of the disk with garbage as well, or they (wanna be crackers) can just look for the junk in some random sector.  Like you mentioned, there are the laser holed disks and hardware keys, but they are both expensive and a pain in the butt for the end-user, which you is the opposite of what you want.  Another configuration that can be used is to save the configuration of the machine that it is being installed to in the most undecipherable format you can think of.  If the program does not find that this is the same system, it requests being installed by the original disk again.  The original disk should be encrypted, compacted, have many sectors that should be checked, and anything else you can think of to make sure that the original cannot be copied.  Once again, you MUST put code-encryption, self-rewriting code, and multiple CRC checks in the program to make sure that it does not get changed.  Among other things, this also protects your program from virii.  If the program detects a change in its code, tell the user that a virus has been detected in the program.  Tell them the program is "VIRUS SECURE", and remember, you have helped the world kill some pirating and kill some viruses.  Feel good.  I hope that I have helped.  Have fun.  Knock some cracking out (well, you can't do it, everything that can be written can be cracked, but you'll piss'em off in the process!). Goodbye.  What is the program that will be sold? -- ------------------------------------------------------------------------------- George Gruschow                                Death do you gronk. ag625@yfn.ysu.edu                              ggruscho@nyx.cs.du.edu