ROM Hack ROM Titles: What does this even mean?

[Themanhunt]

I notice that when I go to download some ROMS (I own the games, but cant be bothered to wait 5 or 6 hours to back up). The title says "Blah blah [MD5]" or "Blah blah [MD7]"...what does this mean? I know MD5 is a type of security thing, but what does it mean in this context?

Chris

 

[Foxi4]

http://en.wikipedia.org/wiki/MD5

They're hashes used for checking whether the download is complete or corrupt.

 

[Themanhunt]

I see. So, what are the advantages of MD5 over MD6, 7 in this context?

 

[FAST6191]

If they are long hex strings then yeah it is a hash, M5 and such like tends to mean how many languages it has (the 5 in M5 being English, French, Spanish, Italian and German -- if someone refers to the multi5 languages in these sorts of sites that is what they mean hence things like "multi5 plus Dutch" or "the usual multi5 languages minus Italian" when people post about new releases) though MD7 might also be a short form of mode7 which is a fairly well known release group.

MD5 vs everything else.

Basic idea of checksums and hashes.

I run a mathematical function over some data and send the result.
If the data is changed then the hash will not match and you can suspect corruption or tampering. The simplest form is probably parity which just adds everything up and tells you whether it is odd or even.
As things go on the functions get more complex and suitable for more things (I can make anything odd or even trivially so it is not suitable as tamper detection, likewise corruption could hit in such a way that it is still odd or even so it is basically useless). For the record the default method for a lot of the time (CRC32) is quite able to be faked -- with a machine at the time I would just wander off and eat something and by the time I was done I could have a file of any CRC32 I so desired. Some GBA release groups added intros to their ROM images and then made it so the resulting crc32 was that of the original game.
MD5 was better than CRC32 but with a reasonable amount of computing power you can still fake it, still it is better.
MD6 was made as a kind of successor to MD5 but is languishing doing not an awful lot right now. It is better but MD5 is still good enough for most purposes, is implemented everywhere, has accelerators in various CPUs/GPUs and so still hangs around.
There is no such thing as MD7 yet.

 

[GHANMI]

MD5, 6 and 7 (and CRC too, for that matter) are methods to verify your download. I assume there is a long string of odd symbols after: that's the hash. There are specific programs an utilities to check the MD5 hash of the file on your end, to compare it with the one appended to the file name the uploader got from his version of the file (or in the nfo / readme thing). If both are identical your file is fine, correctly downloaded, and probably virus-free if the uploader's version is virus free.

These are completely irrelevant to the content of the ROM / file / movie itself.

Now the ones that matter should be
[!] = good dump
J = Japan
K = Korea
CN = China
U = US
E = Europe, or sometimes when the rom has a single language: F (French), I (Italian), G (German), S (Spanish), NL (Netherlands) like with layton games, in which case E usually stands for the UK version.

Tr+Eng = Pre-patched fan-translation

MULTI5 / M5 = has five languages. Sometimes you can find anything from multi7 to multi2
Demo / Beta = leaked Kiosk demo, beta build...
Patched = ap fixed, not always mentioned

There is often a number too, to differentiate between different versions (most demo dumps are unnumbered though, like this xxxx)
It's important, since a game can have many versions, no only by region but sometimes it gets dumped twice when a bugfixed version comes out, like for example Harvest Moon (U)(v1.1) ... (the first then would be renamed v1.0), Tales of Graces Wii, Densetsu no Stafy 3, ....
And cheats / saves / fan-translation patches can work on one but not the other..

You sometimes find the name of the release groups too.
Sometimes (thankfully not many today do this, with the exception of a certain DQIX rom) some of them adds custom homebrew intros, and the ones who don't make a point of them not adding such intros by adding (NoIntro)

EDIT: Oops, ninja'd

 

[Themanhunt]

If they are long hex strings then yeah it is a hash, M5 and such like tends to mean how many languages it has (the 5 in M5 being English, French, Spanish, Italian and German -- if someone refers to the multi5 languages in these sorts of sites that is what they mean hence things like "multi5 plus Dutch" or "the usual multi5 languages minus Italian" when people post about new releases) though MD7 might also be a short form of mode7 which is a fairly well known release group.

MD5 vs everything else.

Basic idea of checksums and hashes.

I run a mathematical function over some data and send the result.
If the data is changed then the hash will not match and you can suspect corruption or tampering. The simplest form is probably parity which just adds everything up and tells you whether it is odd or even.
As things go on the functions get more complex and suitable for more things (I can make anything odd or even trivially so it is not suitable as tamper detection, likewise corruption could hit in such a way that it is still odd or even so it is basically useless). For the record the default method for a lot of the time (CRC32) is quite able to be faked -- with a machine at the time I would just wander off and eat something and by the time I was done I could have a file of any CRC32 I so desired. Some GBA release groups added intros to their ROM images and then made it so the resulting crc32 was that of the original game.
MD5 was better than CRC32 but with a reasonable amount of computing power you can still fake it, still it is better.
MD6 was made as a kind of successor to MD5 but is languishing doing not an awful lot right now. It is better but MD5 is still good enough for most purposes, is implemented everywhere, has accelerators in various CPUs/GPUs and so still hangs around.
There is no such thing as MD7 yet.

Thanks for that, appreciate it and it helps a lot. Thanks for your time.