TLDR; PRNG seeds in the cloud are somewhat predictable. Because sshd generates the keys on boot it's possible to guess the private key on a fraction of the clou

TLDR; PRNG seeds in the cloud are somewhat predictable. Because sshd generates the keys on boot it's possible to guess the private key on a fraction of the cloud hosts. Ubuntu 14.04LTS solves the problem by adding a new source of entropy. They add a early-boot (before sshd) service that fetches data from an external server. In short: `curl http://some-server http://some-server > /dev/urandom` EDIT: Looking for the default server but launchpad seems to be down. Ideally it would be a trusted source like the cloud provider themselves. EDIT2: https://entropy.ubuntu.com/ https://entropy.ubuntu.com/ and the public cert is provided with the package.