I agree. We use a distributed Userify infrastructure to take some of the sting out of key management for our teams; this gives us the ability to tie user authen

I agree. We use a distributed Userify infrastructure to take some of the sting out of key management for our teams; this gives us the ability to tie user authentication into our enterprise directory but still delegate an entire Userify infrastructure on a BU basis, which is pretty awesome. To your point about clouds making it more difficult in the future, it's becoming more challenging to scale the CA across auto scaling groups with dynamic IPs and where you can't control TXT records. We've found that SSH keys are very flexible, and we simply needed a centralized management point (which we have now), but with decentralized operation in case anything is offline along the way. Also, it's very important to us to be able to kill active sessions globally when a user is removed, and there doesn't seem to be any other tools that do that except Userify.