[Merkur]

Please correct me if I am wrong, but I think there is no secure way to store stuff in an virtual environment.

I wish I am wrong - cause my heart always bleeds if I see db passwords in configuration files! But As long as there is a hypervisor you do not control access to - you must trust the owner of the bare metal to (1) honor your privacy (2) be competent to secure his system. Trust is nice, but it is not security.

granted - Confidant and KMS seem better solution than most. Will look into it at more detail. thx for open sourcing it and moving the solution forward.

[akerl_]

Security is a spectrum. There's definitely a path for someone with full local access to the hypervisor and system memory to do some careful reconstruction or other malicious injection, but that attack vector is amazingly rare compared to attacks based on bad protocols for network traffic, bad app-level auth, and insecure storage practices (mixing code and creds, for example).

There's immense value in defending against the kind of attacks where an attacker gets partial access, even if an attacker with omnipotence can compromise you.

[Merkur]

Indeed! After all we live in a world where many ssl private certificates are only protected by OS file system rights on a internet facing server. And clear text database passwords in config files are common, in all content management systems - and even many customer relationship systems!

mysqldump got a CLI argument to provide the password! As far as I know - visible to anyone with some access on the system. the documentation warns about that and suggest to create a config file to store the password.

security is a spectrum - but if it's about password storage in modern web applications live on the lower end.

I am increasingly frustrated by that - and if I raise concerns many admins stick to binary security "storing stuff unencrypted on disk is okay, cause the attacker is inside already" followed by "you must store the key somewhere" it's wrong and it's true at the same time. it's also sad - because not only the users, but also the ppl paying us trust us to keep them save. and we don't. :( we can say "it's a spectrum" and we are truthful - but we just can't keep em safe. I think it's important to recognize that simple fact.

...or is it me who is just meticulous?

[spacehome]

https://en.wikipedia.org/wiki/Homomorphic_encryption

[Merkur]

I did not know such thing is possible. very cool! thx for pointing it out! :)

but still..some rhetorical questions: Is KMS based on this concept? Is it's implementation open sourced? Is it verified to run unchanged in the instance I pay? Who is verifying it? Who is paying the one verifying it? Can I meet him / her to drink a coffee and build trust between us?

pls, do not misunderstand me. I got more trust in the amazon techs than in my own ability to admin a complex linux system on bare metal. But while all that is great progress toward security we still need to make a leap to find a solution. don't we?

[viraptor]

> I did not know such thing is possible.

It's theoretically possible, but right now it's too slow to be practical in usual situations. Just storing and single operations are maybe possible. But for example homomorphic AES takes multiple seconds per each block. And that's still AES-128.

[e12e]

Wait, are you saying HE is feasible for 128 bytes of data, if you can allow seconds for de/encryption? That'd be plenty usable for read-at-startup 128 bit api keys for micro-services, disk encryption keys etc?

(Granted, in this context, having a de-crypted disk at run time under a vm would be considered insecure - but still better (for some use cases) than man alternatives)

[viraptor]

AES has a block size of 128 bits, not bytes. Using the fastest reported method, that would be 2s/block, so 16s/128bytes.

So in practice, probably that's the case - you could use homomorphic encryption for very infrequent operations on KEKs for example.

[e12e]

Well, actually I was wrong twice, so it cancels out ;-) 128 bits is enough for many things. Eg. 128 bit keys. Too little for an ECC secret key, but not by much.