[$] Two approaches to x86 memory encryption

Techniques for hardening the security of running systems often focus onaccess to memory. An attacker who can write (or even read) arbitrarymemory regions will be able to take over the system in short order; even theability to access small regions of memory can often be exploited. Onepossible defensive technique would be to encrypt the contents of memory sothat an attacker can do nothing useful with it, even if access is somehowgained; this type of encryption clearly requires hardware support. Both Inteland AMD are introducing such support in their processors, and patches toenable that support have been posted for consideration; the twomanufacturers have taken somewhat different approaches to the problem,though.