Kernel/XboxSignatureKey
This is used to find the Xbox Public RSA-2048 Key. This key is used to verify the signed Xbe executables.
struct RSA_PUBLIC_KEY
{
char Magic[4]; // "RSA1"
unsigned int Bloblen; // 264 (Modulus + Exponent + Modulussize)
unsigned char Bitlen[4]; // 2048
unsigned int ModulusSize; // 255 (bytes in the Modulus)
unsigned char Exponent[4];
unsigned char Modulus[256]; // Bit endian style
unsigned char Privatekey[256]; // Private Key -- Big endian style
};
struct RSA_PUBLIC_KEY xePublicKeyData;
XBE signing process
The XBE signing process consists of two stages:
1. Calculate a SHA-1 hash of the contents of each of the XBE sections and store it in a table in the XBE header.
2. Calculate a SHA-1 hash of the XBE header, except for the magic 'XBEH' value and the digital signature field. The hash is then encrypted with a 2048-bit RSA private key. The signature of all official titles has been encrypted with The resulting encrypted hash signature stored near after the XBE header XBEH magic field, in the digital signature field.
XBE signature verification
When an Xbox verifies an executable, a similar process is followed:
1. All the XBE section hashes are recalculated and compared to the ones stored in the XBE header section table. If these don't match, verification fails.
2. Calculate a SHA-1 hash of the XBE header, except for the magic 'XBEH' value and the digital signature field.
3. The digital signature field from the XBE is decrypted with the 2048-bit RSA public key and compared to the SHA-1 hash of the XBE header. Finally, if the two values match, the game is verified.
