Understanding the RSA Signature

[Choco]

Understanding the RSA signature

I have noticed lots of confusion about this lately, so I wanted to post this to help clarify things for those who don't understand how the RSA signature works. With that being said, let's get started

-First off, there are two different keys used on the RSA signature: Public and Private. The public key is responsible for decrypting the RSA signature to check it, while the Private key is responsible for generating the RSA signature.

-In the Black Ops fastfile, the RSA signature starts at 0x3C and ends at 0x13B (giving it a total length of 256 bytes). Essentially, the RSA signature is a hash of the encrypted data contained inside the file. The signature is generated by Treyarch when they create the fastfile using their private key. If you change anything inside a fastfile at all, the RSA signature will not match the file and the game will abort loading the fastfile resulting in a blackscreen.

-So how does the game know that the RSA signature doesn't match the fastfile?

Well, the EBOOT.BIN (t5mp_ps3f.self for multiplayer) contains everything the game uses to load, and it includes a check on the RSA signature. So, in order to run a modded fastfile you need to modify the EBOOT.BIN to skip the RSA signature check. Lucky for you, I have already done this for everyone and you can download an EBOOT for your region with RSA signature checks removed .

-So, why can't I just use a modded fastfile online?

If you have a modified fastfile you need a modified EBOOT, and as many of you probably know a modified EBOOT.BIN cannot be used on any firmware above 3.55. This is because Sony has changed the keys they use for encrypting executables after the whole custom firmware incident.

-Someone found the Public Key, so why can't they find the Private Key too?

The public key has it's name for a reason. Since the game cannot load an encrypted file, it has to decrypt it before runtime so the key has to be stored somewhere. The public key is contained inside the EBOOT.BIN and gets loaded into the SPU when you launch the game, and from there it is used to decrypt all fastfiles. The private key, however, is not stored anywhere in the game files. It is only used by treyarch to generate RSA signatures for their game update fastfiles.



This should help to clarify things for some of you, but if you have any questions feel free to ask. I hope you all learned something by reading

[Pauly]

Why would it get released? Think about it would you want Black Ops to be fucked up just like all the other CODs are/were Or every 12 year old running around thinking he's cool because he has mods? Didn't think so

[ᴠevo]

So.. We can't make online cls for the moment.

[hiTeddy]

Who cares. I want the save data utility keys. Black ops hacks online FTW!! :ftw:

[dilyfe95]

what software you use for modificed eboot

[xRoyalFlush-]

how can we get a eboot with xp lobby for ps3?

[wfghackz]

Thanks Alot Now My understanding Of this is all Good Thanks

[BuC-ShoTz]

choco the total length of the sig is 256 bytes (RSA256)
256 decimal = 0x100 hex
so basically the rsa sig is an unhackable hash/checksum

The public key is responsible for the encryption/decryption of the FastFile

to decrypt the ff's the game uses the salsa20 key

the private key is what activision uses to make the rsa sig
the public key is what the game uses to verify the rsa sig

---------- Post added at 09:32 AM ---------- Previous post was at 09:28 AM ----------

Who cares. I want the save data utility keys. Black ops hacks online FTW!! :ftw:

its already online without the save key.

---------- Post added at 09:33 AM ---------- Previous post was at 09:32 AM ----------

So.. We can't make online cls for the moment.

mods are online just not a cl

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now is anybody interested in modding MW3???????
could use some help...

[Choco]

choco the total length of the sig is 256 bytes (RSA256)
256 decimal = 0x100 hex
so basically the rsa sig is an unhackable hash/checksum


to decrypt the ff's the game uses the salsa20 key

the private key is what activision uses to make the rsa sig
the public key is what the game uses to verify the rsa sig

---------- Post added at 09:32 AM ---------- Previous post was at 09:28 AM ----------



its already online without the save key.

---------- Post added at 09:33 AM ---------- Previous post was at 09:32 AM ----------



mods are online just not a cl

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now is anybody interested in modding MW3???????
could use some help...

Well I guess I got some stuff messed up I'll fix my post.

And I would be glad to help you out with MW3.

[xKtF]

So you need a modded eboot to run a modded patch.. But you cannot run modded eboots on any firmware above 3.55 because sony changed the keys they use for encrypting executables, so then how are people hosting XP lobbies? I have a few theories but I haven't tested 'em out yet.. I know you won't tell me straight up how to host them, but can you just give me like an idea of what people actually mod? I thought TheUnkn0wn, hunter128, and you were the only people that can put binds in the SVG..? I'm a bit confuzzled. :drack:

there deff not the only ones to host only about 15people host

[TheFuziioN-]

Most people know by now that it's through save mods. I can't really discuss what exactly is involved right now.

I know exactly everything. Except The Instruction