Intel microcode update encryption

[Travis H.]

http://microcodes.sourceforge.net/

There you can find a PDF reviewing the microcode update feature.

Apparently the updates from Intel are 2048 bytes long overall, and
have a 4-byte checksum, and are "encrypted" using some kind of
mechanism on the processor.  Since they don't (to my knowledge)
express any instructions for doing encryption natively, they likely
don't have any just for the microcode update, so it *should* be
something simple, relying more on obscurity and the small size of the
updates than cryptographic strength.

Still, most of the details remain unknown to all but about ten guys in Intel.

Writing your own "jump to ring zero" instruction is left as an
exercise to the reader.
--
"Curiousity killed the cat, but for a while I was a suspect" -- Steven Wright
Security Guru for Hire http://www.lightconsulting.com/~travis/ -><-
GPG fingerprint: 9D3F 395A DAC5 5CCC 9066  151D 0A6B 4098 0C55 1484

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