okay, i have asked about crc before and found some tuts on it. but i still can not really know what the assembler code for this really looks like. i have been tring to crack a screen saver, but it detects it has been cracked. the ss which is pretty cool, at least i think is called firemagic (http://www.fpsoftlab.com/firemagic.exe) if someone could look at this could give me a little help.

I dont think that it use classic crc algo.However this programs crc check is easy I guess.Only one reference to error messsage.

I didnt check reg check.I have just changed one byte and changed above jump.It worked.Be carefull that this crc call is called two times.I guess you can patch your self this one also if needed.

I dont know how much u know about crc ing but pretty much all it does is XOR a sectionbyte by byte or word by word....(etc.) to ensure that it does not change

normally in the following fashion of somesort

/************************************
* This C code snippet Wont show u what an *
* asm code will look like but will let understand *
* the theory behind it... I hope *
***********************************/

int i=0;
char *SectionToBeChecked;
char GoodCheck = WhateverIsValueOfGoodCheck;
char XORValue = 0;

/************************************
* iterate through the section Byte by Byte
* XOR'ing the value of each byte with the
* current XORValue variable and storing it there
* so any one different byte should change the
* final value of the variable
***********************************/
while(i<LengthOfSection)
{
XORValue^=SectionToBeChecked[i++];
}

/* test the variable agianst the good */

if(XORValue == GoodCheck) // passed the CRC
else /* DOH!!!!!!!! But Ma-arge! */

anyway... find a tiny loop that is just XOR-ing a String and you should have found a CRC procedure
then u got all sorts of ways to fix your problem

gl hope i helped

Off course in this call there is a xor and shift operations.I mean classic CRC32 or CRC16 standard. like this for example

thanks,
i finally know what it is.
brill0