[throwaway150]

> Any recoverability sounds very bad.

PRNGs are not meant to be cryptographically secure. If you don't want recoverability by all means use SHA512 or a proper CSPRNG.

But saying PRNGs are bad because there is recoverability is like saying salt is bad because it isn't sweet. PRNGs are not meant for non-recoverability and salt isn't meant to be sweet.