By definition anything can be cracked if it can run - the best protection would be to hash the whole program - then even legal users couldn''t use it! Don''t worry about inline checks ruining the program. Just so long as you don''t put it in really frequently called functions you won''t notice a slow down worth talking about. Doing relatively simple checks say in a dozen places in the rendering loop of the game will probably be enough to deter most from sucessfully cracking it whilst causing no speed issues.
BTW: Point about data/code caches - surely softice/favourite debugger must sync mem & caches before its looked at?
How do i make my app stop working after x days ?
Memory <--> cache coherency is guaranteed. I doubt SoftICE flushes the trace cache every time you write to memory.
What I''m talking about is messing with the cracker: write some godawful SMC that is really hard to trace. The fact that I and D caches are separate is one thing that might be used to confuse the poor guy. It''d be cheating to step through the code in a debugger, so check for side effects (i.e. this took more than 1 ms to execute) and throw a wrench in the calculation. While I agree that anything can be cracked, unraveling a determined attempt at obfuscation is hell, and would stop all but the most determined and best guys (even then, costing them a lot of time). If you can arrange it that each copy of the game is slightly different, making a generic patch hard, even better.
What I''m talking about is messing with the cracker: write some godawful SMC that is really hard to trace. The fact that I and D caches are separate is one thing that might be used to confuse the poor guy. It''d be cheating to step through the code in a debugger, so check for side effects (i.e. this took more than 1 ms to execute) and throw a wrench in the calculation. While I agree that anything can be cracked, unraveling a determined attempt at obfuscation is hell, and would stop all but the most determined and best guys (even then, costing them a lot of time). If you can arrange it that each copy of the game is slightly different, making a generic patch hard, even better.
Re: #if
If in C (and family (ie. ++)) you put
#if FULL_VERSION
//(-- code --)
#endif
around things (such as saving code) that need not be accessible in the demo version they will not be included by the compiler, and therefore it is easier for a cracker to right a new version than to crack your program.
Re: Cache Deamons
I have no idea what any of you cache deamons are talking about but if you expalian it to that author of ollydebug i will be very happy...
RE: Zanza
That site is very good, but could do with a revamp (that bit at the top about dongles probablly put most people off...
http://www.searchlores.org/protec/protec.htm
Re: Petewood
What you do is you do it, and all the peps playing cracked games get a crappy version (serves them right), and later on you release a messge (press release) saying that the cracker failed... (and anyone who e-mails you with a complaint about the biut you made harder can get their e-mail addresses sold (so you get revenue from them anyway!)
If in C (and family (ie. ++)) you put
#if FULL_VERSION
//(-- code --)
#endif
around things (such as saving code) that need not be accessible in the demo version they will not be included by the compiler, and therefore it is easier for a cracker to right a new version than to crack your program.
Re: Cache Deamons
I have no idea what any of you cache deamons are talking about but if you expalian it to that author of ollydebug i will be very happy...
RE: Zanza
That site is very good, but could do with a revamp (that bit at the top about dongles probablly put most people off...
http://www.searchlores.org/protec/protec.htm
Re: Petewood
What you do is you do it, and all the peps playing cracked games get a crappy version (serves them right), and later on you release a messge (press release) saying that the cracker failed... (and anyone who e-mails you with a complaint about the biut you made harder can get their e-mail addresses sold (so you get revenue from them anyway!)
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