OpenBSD is a natural fit for the privacy.fish workflow because SSH tooling is available by default.
Generate a key
Create a dedicated SSH key for privacy.fish:
ssh-keygen -t ed25519 -f ~/.ssh/privacy-fish
Add the public key from ~/.ssh/privacy-fish.pub to the signup form.
Keep a backup key
Add a second key from another trusted device if you have one. Recovery only works through configured backup SSH keys.
After provisioning
After your account is created, use the connection details from the getting started guide and your local OpenBSD SSH / SFTP tools to access the service.