help with a ps2 savegame checksum

[hardx36]

so i trying to mod a svr 11 ps2 savegame but the problem is that the savegame use an checksum, i have already searched info about checksums but i cant figure out what is the checksum used for that save

so somebody can help me to identify the type of checksum and how to make a custom one after edit the savegame??

here are two savegames: http://www.mediafire.com/?t5fxgrgk6gfmda5 i think the cheksum is the first 16bytes of the file

[Pyriel]

It can be a little hard to determine the algorithm just based on its output. However, if it's actually a 16-byte hash, you're probably looking at MD5 or some variation on it. It's not unusual for these things to either use obscure or disfavored variations on certain algorithms, or to add their own odd twists to them.

[hardx36]

so basically is not possible to determine the type of hash just with the savegame however is not a simple md5 is ther other way to indentify the hash used??

[Pyriel]

Well, it might be a vanilla MD5, that's something you have to check into. http://en.wikipedia.org/wiki/MD5

The simplest place to start is to look for its seed values or the initial state tables. Either check the executable or pull a dump while you're on the loading screen. If it turns out to be a standard MD5, the next question you have to ask is, "what data is hashed?" It might be the entire contents of the save file, excluding the check sum, or it might just be some segment of it that seems ripe for hacking. You can also look for an MD5 tool, and see what you get out of generating a hash for the whole file (minus the check sum again).

[hardx36]

well that seems to be very complicated for me because i have no experiencie with hashes i can make the dump but i dont know what to search however thanks for your help