Maybe I'm missing something, but it seems as though you're asking candidates to ...

tonyhb · on March 2, 2015

You can do a search on public PGP key servers such as the MIT key server. His email shows this result:

https://pgp.mit.edu/pks/lookup?search=daniel%40utilityapi.co...

PGP key here: https://pgp.mit.edu/pks/lookup?op=get&search=0xE7F6FAD172EFE...

diafygi · on March 2, 2015

Bingo, you passed the first test. This job entails a lot of figuring out what and how to find the things you need to solve a problem. The lack of a public key in the job posting is intentional.

totony · on March 2, 2015

He did not seem to ask for the encrypted message to be sent to a specific key, challenge him?

Someone send an encrypted message with some hint about the priv key and see if they are interested/good enough to decrypt your resume