Section Rules - Halo 3 Modding Q&A

[SPARTAN-OMEGA]

Im getting confused because I cant read horrible english...and sneaky, its because the file is resigned

[Tural]

Im getting confused because I cant read horrible english

Then maybe you should stop posting.

[Aumaan Anubis]

[Philly]

Im getting confused because I cant read horrible english

Then maybe you should stop posting.

Oh, come on Tural. It's not that bad.

[sneakyn8]

Im getting confused because I cant read horrible english...and sneaky, its because the file is resigned

i know its resigned but how is it that if the data that the signature represents is changed it can still have the same signature and modified data

[Tural]

Oh, come on Tural. It's not that bad.

What?..
Your comment makes sense in relation to him saying he can't read it, but not my criticism of his criticism. Contextually, you don't make any sense.

[Philly]

Neither does your...
Sorry.

[Tural]

His comments about not being able to read it contribute nothing, especially when others can.
If he's going to continue to post such comments, they are going to be necessary and pointless.
I told him to stop posting such comments for the aforementioned reason.
That makes sense.

You said it's not that bad. What isn't that bad? I never said something was bad.
That doesn't make any sense in this situation.

[Anthony]

Im getting confused because I cant read horrible english...and sneaky, its because the file is resigned

i know its resigned but how is it that if the data that the signature represents is changed it can still have the same signature and modified data

if the data changes the signature will change... theres no way around this

[SPARTAN-OMEGA]

We can resign it because we know how to change the signatures so they are the same as the unmodified version.

[Tural]

Not entirely. Technically the proper way we do it is by recalculating the signature and adding the one to match the calculation the game will do on the map. I'm aware that for DLC maps the original signature could be replaced, but I'm not entirely sure why this lapse in security was present.

[LuxuriousMeat]

Not entirely. Technically the proper way we do it is by recalculating the signature and adding the one to match the calculation the game will do on the map. I'm aware that for DLC maps the original signature could be replaced, but I'm not entirely sure why this lapse in security was present.

It wasn't, you still had to calculate the CRC of the file. I don't remember exactly how it was done, but I believe you had to write the original signature to the header, then you had to calculate the CRC checksum and write it to the end of the file, or something along those lines.

[Tural]

Ah, that makes sense.

[Anthony]

Its because Halo 2 was not really a signature it was a simple checksum

and the way Xor checksums works are really simple and a simple calculation of some data could help us modify the file so that it would be the same signature

[sneakyn8]

so im still confused what are you doing to the file to keep the modifications and original signature

[Tural]

You don't understand the concept of a signature, despite it being explained as best as it can be, for the most part. We can't really state what it is any differently. You're not getting it conceptually, and there's not a whole lot we can do to help you there.

You do not keep the original signature. You make a new signature.
The signature is a representation of the entire file.
When you make a change, the old signature is a representation of the old file, not the newly modified file.
For the game to detect the file as being correctly copied, it must check the signature against the file.
You change the signature so the file matches the signature, and thus the game knows it was correctly copied.

It just is. I can't make it any more clear than how I already have. It works because it does and that's how it is.

I'll make an example that is not at all like a signature, but should help you get the concept.

Here is a given file:

Code: Select all

abcdefghijklmnopqrstuvwxyz1234567890

A signature for this file is generated by taking every letter and reversing them:

Code: Select all

0987654321zyxwvutsrqponmlkjihgfedcba

The game checks the signature with the original file and it matches. However, if we change the file to be this:

Code: Select all

aaaaaaaaaaaaaaaaaaaaaaaaaa1234567890

The signature is still the original text reversed. The game sees they do not match now, and it does not allow the map to be executed. We must make a new signature by doing the same reversal process:

Code: Select all

0987654321aaaaaaaaaaaaaaaaaaaaaaaaaa

Now when the game generates a signature, it will match the signature in the file, and it will know the file is authentic, and allow it to be run.

That is about the absolute lowest level of understanding I can bring it to. If you can't understand it still, I can't help you.

[SPARTAN-OMEGA]

That was a good explination. I think if he doesnt understand it after that he doesnt need to worry about modding anything for Halo 3

[sneakyn8]

i understan now thankyou

[Anthony]

i understan now thankyou

thats right.. you better understand...

[SPARTAN-OMEGA]

Lol