encrypted key

Can you please elaborate on what exactly is your question/concern regarding encryption key?

If you want to have encrypted forms, please see this guide:

Encrypted-Forms-and-How-to-Use-Them

Please note that only you have access to your private encryption keys, we do not store any private encryption keys on our end, as such, if you happen to loose your encryption key, we highly suggest to turn off encryption asap so you'll be able to read new submissions.