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OG Xbox Forums => Software Forums => Xbox Bioses => Topic started by: Wooger on July 18, 2003, 03:51:00 PM

Title: Bios Hash And Xbe Signing
Post by: Wooger on July 18, 2003, 03:51:00 PM

Ok... looking to learn and verify I have this down correctly but....


Just out of curiosity if you had the original hash's to the MS kernels,  could you not sign .xbe with this hash and produce a "MS signed" executable allowing you to boot anything on the xbox?


Wooger

Title: Bios Hash And Xbe Signing
Post by: BenJeremy on July 18, 2003, 04:11:00 PM

QUOTE (Wooger @ Jul 18 2003, 07:51 PM)

Ok... looking to learn and verify I have this down correctly but.... Just out of curiosity if you had the original hash's to the MS kernels,  could you not sign .xbe with this hash and produce a "MS signed" executable allowing you to boot anything on the xbox? Wooger

Why, golly, gee! You've discovered it! It was so damn simple, and in front of us this ENTIRE TIME!!!!















Um, no.

The signature keys for an XBE are 2048 bits in size (EXTREMELY LARGE). There are TWO keys: A Public and a Private key. The BIOS contains the PUBLIC key. You cannot use this in any way to sign an XBE, only to verify the resulting signature from the PRIVATE key.

Three parts: Private key, Signature (resulting from the private key applied to the data), and Public key (used to verify the signature belongs to the data).

M$ Keeps the Private key under very close secutiry, probably locked in a vault that would make James Bond shudder.

Title: Bios Hash And Xbe Signing
Post by: Wooger on July 18, 2003, 04:44:00 PM

QUOTE (BenJeremy @ Jul 19 2003, 01:11 AM)

QUOTE (Wooger @ Jul 18 2003, 07:51 PM) Ok... looking to learn and verify I have this down correctly but.... Just out of curiosity if you had the original hash's to the MS kernels,  could you not sign .xbe with this hash and produce a "MS signed" executable allowing you to boot anything on the xbox? Wooger Why, golly, gee! You've discovered it! It was so damn simple, and in front of us this ENTIRE TIME!!!! Um, no. The signature keys for an XBE are 2048 bits in size (EXTREMELY LARGE). There are TWO keys: A Public and a Private key. The BIOS contains the PUBLIC key. You cannot use this in any way to sign an XBE, only to verify the resulting signature from the PRIVATE key. Three parts: Private key, Signature (resulting from the private key applied to the data), and Public key (used to verify the signature belongs to the data). M$ Keeps the Private key under very close secutiry, probably locked in a vault that would make James Bond shudder.

Shooting down every dream... crying ...  damn icecrem man    j/k

So your saying the private key is the "key"....

Wooger

Title: Bios Hash And Xbe Signing
Post by: BenJeremy on July 18, 2003, 04:47:00 PM

Yes... the Private Key is the Holy Grail for Xbox hackers. There is one effort under way to "brute force" the key with distributed computing.

Title: Bios Hash And Xbe Signing
Post by: vintage_guitar on July 18, 2003, 08:59:00 PM

one of the things we'd give our left nut to salvage ~