[TomFrost]

KMS is not a centralized secret database -- it's a hosted Hardware Security Module. There is no way to store your service's secrets in it for later retrieval, unlike the solutions listed in the article. I suppose an argument could be made that it still provides a single point of failure, however the risk level of KMS and the SLA it provides is far lower than what one might encounter by maintaining their own server cluster.

[timdierks]

AWS KMS does not use HSMs. Amazon says it runs on HSAs ("hardened security appliance"), but they don't provide a lot of info on what that means. I would presume that the only thing keeping a limited number of Amazon employees from accessing your keys is policy.

I agree that using AWS KMS is the same architecture as using some other KMS that you run yourself, you just garner the benefit of their software and operational capacity and you buy service; this is the same as any other PaaS service at Amazon or some other vendor.

What's the value of Cryptex, though? Why not just store KMS-wrapped secrets in your config file and have Amazon unwrap them? Then you wouldn't be dependent on any local crypto implementation and you could use other KMS features, such as AEAD.

[rpedela]

It literally says AWS KMS uses HSMs in the introductory paragraph.

https://aws.amazon.com/kms/

[timdierks]

I'm relying on https://d0.awsstatic.com/whitepapers/KMS-Cryptographic-Detai.... There are HSMs, I guess, but they'r only used to back up the keys when they're stored offline for durable backups. I hadn't seen the claim on the main page, but I'd consider it to be misleading, presuming that the cryptographic details whitepaper didn't totally misstate the design.