MD5 codes of good roms (idea for n64 emulators)
- Thread starter Hacktarux
- Start date
64 bit CRC wouldn't be a great substitute. But if you're worried about that then there are plenty of other algorithms around.
MD5 is licensed freely by RSA however and is even implemented in the GNU application md5sum (part of textutils i think) and is also used in the open source ids tripwire. All they ask is that you acknowledge that you have used their algorithm.
MD5 is licensed freely by RSA however and is even implemented in the GNU application md5sum (part of textutils i think) and is also used in the open source ids tripwire. All they ask is that you acknowledge that you have used their algorithm.
OP
- Thread Starter
- #27
OK, i think that i have enough codes for good roms, i have not check all the things, but it seems that everything is right : a good rom has always the same code and if only one bit is altered, the code is totally different.
I don't think we need to have bad roms code. I you see a reason, let me know.
And cyberman:
Usually, i don't use patent code but i don't see any problem in this case. This algorithm is used in many free products and it is free even in a commercial product. And one last thing, i am using an independant implementation that can be found in sourceforge.
I don't think we need to have bad roms code. I you see a reason, let me know.
And cyberman:
Usually, i don't use patent code but i don't see any problem in this case. This algorithm is used in many free products and it is free even in a commercial product. And one last thing, i am using an independant implementation that can be found in sourceforge.
Doomulation
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It appears to me that every rom has a diffrent code.
It would be the same to take the CRC code and check.
It would be the same to take the CRC code and check.
Doomulation
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Oh...
Bah! Too confusing, I'll just use the old fasion way of using the CRC
Bah! Too confusing, I'll just use the old fasion way of using the CRC
OP
- Thread Starter
- #31
Doomulation said:Oh...
Bah! Too confusing, I'll just use the old fasion way of using the CRC
I don't think you understand what i am trying to make.
I am not searching to know how to identify a game, i am searching how to detect if a rom is a good or bad dump. I think it is usefull to integrate it in emulators because the goodn64 tool is not easy to understand by a newbie. Maybe, i'm wrong but i can see in this message board that it's the origine of many questions.
Hmmm how about a 'good' plugin for that? IE an optional plugin for emulators that allows them to send the data for a rom to the plugin and indentify if that rom is good or not. This prevents having to have each emulator author code it into there emulator. Simplifies using the MD5 code as well since the plugin would do all the detection and calculation.Hacktarux said:
Cyb
OP
- Thread Starter
- #34
Cyberman said:
I thought that the codes could be integrated in the current ini files. To calculate the message digest, there's only 3 line to add in the code :
md5_init(&state);
md5_append(&state, (const md5_byte_t *)buf, size);
md5_finish(&state, digest);
The app needs to be linked to the md5 library and buf is the rom in the z64 format.
But if an emu author ask me to make a dll i can do one
Generally, i prefer plugins, but for this, i don't know what is better : loading a plugin and calling the function will probably need more lines of code than implementing it directly.
Doomulation
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I very well understand what you are trying to make, but it is still very confusing to me.Hacktarux said:
My utility as you can see below, has the ability to check if it's a good dump through a database with CRCs. And at least one of my users are missing like 20 known n64 roms, so that's no problem.
OP
- Thread Starter
- #37
Hey doom, i don't have anything against you, but your crc check is totally useless. I have just check your utility and it just extracts the crc code stored in the rom header. + you have made useless work because these code were in the pj64 rdb file. So your utility just check 8 bytes of the rom, if these 8 bytes are right, you assume that all the other bytes are right !
MD5 technic checks every bytes of the rom, if you change one bit in the file, the result code is totally different.
MD5 technic checks every bytes of the rom, if you change one bit in the file, the result code is totally different.
Doomulation
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True, I could do it your way, but I am confused on how it works.Hacktarux said:
It would be good to just compile a damn DLL of which could check this and return true or fals depending on whether its good or not.
and btw: pj's rdb for example has a list of if it good or bad, for example. By checking the CRC!
The rom-header CRC, nothing like yours.
OP
- Thread Starter
- #39
I know that pj64 can detect some bad dumps but generally it can't. Maybe i will make a dll, but if not, here is what you have to do :
you load the rom in a buffer.
then you byteswap the rom so it is in z64 format : it has to begin with 0x80 0x37 0x12 0x40
you calculate the md5 code of this buffer (there's many dlls to do that available on the net in the language you want)
and then you compare the result with the codes you can find in the files posted in this thread
Hope it helps you to understand that.
you load the rom in a buffer.
then you byteswap the rom so it is in z64 format : it has to begin with 0x80 0x37 0x12 0x40
you calculate the md5 code of this buffer (there's many dlls to do that available on the net in the language you want)
and then you compare the result with the codes you can find in the files posted in this thread
Hope it helps you to understand that.
Doomulation
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I understand THAT.Hacktarux said:
But generally, what I don't understand is how to calculate the code.
And about the DLL, it can call c/c++ dlls. Just needn't do much trouble like saying FileP for argument of something that can do as a long...