SHA-1

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Topic review
   

Expand view Topic review: SHA-1

by RomCenter » Fri Apr 20, 2007 11:08 am

Maybe not in 3.00. I want to finish that version as it is before adding new feature.

by BigFred » Sun Apr 15, 2007 10:08 am

This sounds like a perfect solution. I hope we'll see this soon :)

by RomCenter » Wed Apr 11, 2007 9:46 am

I identified 5 cases:

If datafile provide:
- crc : check crc (old dat)
- sha-1 : check sha-1 (can be used to force sha-1 check on some roms from the dat)
- crc + sha-1 : check crc + option to individual sha-1 check (normal case with mame)
- no signature : check name and size (samples)
- chd + sha-1 : check name + option to individual sha-1 check (chd)

If I remember well, chd have two ways to check theirs validity: a fast one (only compare stored sha-1 with mame sha-1) and the slow one (calculating the real sha-1 on the 300MB+ chd)

by Hakkk » Tue Apr 10, 2007 6:31 pm

Wanderer wrote:Hi Eric.

Well, i don't know if you decide to implement this but if you do, it would be nice if you also add an option to let the user decide which algorithm he wishes to use in each DB.
An option for a DB is a good thing. And I think a command item like "SHA-1 check" in right-click menu will be convenient if users do not want to check every sets in a DB. Users can use this right-click command in single/multiple roms and sets, just like the "fix game" in RC2.x

by Wanderer » Tue Apr 10, 2007 5:08 pm

RomCenter wrote:The main problem with sha-1 is that it will greatly slow down rom analyse.
Hi Eric.

Well, i don't know if you decide to implement this but if you do, it would be nice if you also add an option to let the user decide which algorithm he wishes to use in each DB.

by RomCenter » Tue Apr 10, 2007 12:49 pm

Yes, I know that some mame fakes appear some years ago, but not for gba.

The main problem with sha-1 is that it will greatly slow down rom analyse.
crc is fast and with zipped roms, you don't even have to calculate the crc because zip archives store files crc in their structure.
Calculating the sha-1 means extracting the rom and apply the sha-1 algo.

Most of the program is already there. The biggest part is the database structure if I keep at the same time crc and sha-1.

Sha-1 calculation is simply a new plugin. It can be developed by anyone (sha-1 algo is freely available) and it should already work with the current version (with an adapted datafile of course).

by Hakkk » Tue Apr 10, 2007 10:26 am

Yes. CRC32-fake roms for MAME exist for a long time, and recently some GBA roms too.
News in nointro homepage:

27-mar-2007

Rising Scum altered #2720, but Sir VG redumped it.
Please note that CRC32 does not change. Only MD5 and SHA-1 do.
Freaks in that crew are reading math books, lol!

and

31-mar-2007

Rising Sux altered #2722, but CharlieF redumped it.
Please note that CRC32 does not change. Only MD5 and SHA-1 do.
Main GBA dat release #2723.

by RomCenter » Tue Apr 10, 2007 9:36 am

Is it true ?
Can someone confirm ?

Anyway, adding sha-1 could be a good thing.
I keep that in the todo list, but I prefer finish the first release and adding new things later (could be in 3.1 if it's really needed).

SHA-1

by BigFred » Mon Apr 09, 2007 4:09 pm

Is it possible to add SHA-1 support in the next update? Some funky group is starting to hack their introed, cracked whatever releases to the same crc as the good dumps and a way to check better hashes is highly needed now. Thanks in advance!

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