[Cryptography] Speeding up Linux disk encryption

Howard Chu hyc at symas.com
Sat Apr 10 18:14:41 EDT 2021


Jerry Leichter wrote:

> 3. There was a very neat paper published a coupld of years ago that used the virtualization hardware on x86's chips to "turn virtualization inside out."  The problem it attacked was how to run a trusted process on an untrusted OS.  Very roughly, when a process was actually running in user mode, its memory was unencrypted.  Whenever it switched to the operating system, the hypervisor encrypted all its memory.  So the OS never had access to unencrypted contents of a process's memory space.  (The encryption was authenticated, so if the OS tried to change things, on the next switch back to it, that would be noticed.)  Since file I/O has to go through the OS, as I recall the process's files would end up containing only encrypted data as well.

Sounds a lot like how AMD's Secure VMs work today on Epyc processors, except the keys are
held inside the CPU and never appear in memory. AMD's setup means each VM's RAM is encrypted
so the host OS can never peek inside the guest's memory.

https://www.amd.com/en/processors/amd-secure-encrypted-virtualization
> 
> I wish I had a reference.  I suspect the research was done at Microsoft, which actually supports broadly similar kinds of things (e.g., processes that are shielded against even the most privileged operators of a cloud data center) in Azure.
> 
>                                                         -- Jerry
> 
> _______________________________________________
> The cryptography mailing list
> cryptography at metzdowd.com
> https://www.metzdowd.com/mailman/listinfo/cryptography
> 


-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/


More information about the cryptography mailing list