hiera-eyaml is a backend for Hiera that provides per-value encryption of
sensitive data within yaml files to be used by Puppet. The Hiera eyaml
backend uses yaml formatted files with the .eyaml extension.  The encrypted
strings are prefixed with the encryption method, wrapped with ENC[] and
placed in an eyaml file. You can mix your plain values in as well or
separate them into different files.

WWW: https://github.com/voxpupuli/hiera-eyaml