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Comment by noir_lord | Hacker News Reader

This is answered directly in the article where they suggest you take advantage of their encryption offerings.

> If Amazon faced a subpoena that required it to keep the order secret, such encryption would be useful to customers. “If the data is encrypted, all we’d be handing over would be the cypher text,” he said.

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It doesn't protect you meaningfully as an EC2 user, since there's no (current, on AWS) way to do an "encrypted VM" where everything including memory is encrypted and the hypervisor can't be coerced into decrypting it en masse.

It does protect you for S3 if and only if you conduct the crypto outside AWS and generate/manage the keys yourself (e.g. how tarsnap does it). It may protect you for some of the other AWS services IFF you use them in the same hybrid way, but I don't know of anyone who uses AWS's database services without just using EC2 nodes primarily to talk to them.

AFAIK there is no curent, practical "encrypted VM" that can protect itself from the hypervisor. Homomorphic encryption can theoretically do that, but is very slow and unproven right now.

There are tricks you can do with Intel TXT to trust only the CPU and cache (TRESOR is an example) http://www1.informatik.uni-erlangen.de/tresor

It's missing a few elements you'd need to build a really awesome secure cloud, though. (actually, intel hardware was missing it)

I only glimpsed it some years ago, but I got the impression that "anything the vendor can do, the attacker can circumvent one level deeper", especially as a criticism of TXT:

http://www.blackhat.com/presentations/bh-dc-09/Wojtczuk_Rutk...

STM fixed that particular set of problems in 2010/2011. There are still issues with making all of this stuff useful, though.

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