Preparation for the certifcates seminar

See merge request pv080/pv080_crypto!4

Add hashing to the API

See merge request pv080/pv080_crypto!3

While both words are correct cryptographic is used much more. You can
check Google Books Ngram Viewer to see the huge difference.

Yes, parsing YAML and producing a Bash commands out of it might not have
been the brightest of ideas, when it fails on a single white space.
Thanks to whoever thought of that. I'll sleep better now knowing there
is one more thing to keep in mind.