Wow, that's some fantastic work!. Just to quote the conclusions of what Ben Hawkes found: Several previously undocumented header fields have been identified an

Wow, that's some fantastic work!. Just to quote the conclusions of what Ben Hawkes found: Several previously undocumented header fields have been identified and described. The results suggest that microcode updates are authenticated using a 2048-bit RSA signature. The RSA signature operation appears to be constant-time (i.e. unaffected by changes to the supplied exponent, modulus or signature value). Timing analysis reveals 512-bit steps correlating to supplied microcode length. This is a common message block size for cryptographic hash functions such as SHA1 and SHA2 The RSA signature was located, and the signed data is a PKCS#1 1.5 encoded hash value. Older processor models use a 160-bit digest (SHA1), and newer processor models use a 256-bit digest (SHA2).