Casually: means you have done a casual verification that the key is owned by the person who claims to own it. For example, you could read the key fingerprint to the owner over the phone.
Azaletik: gako horren jabea omen dena hala dela azaletik egiaztatu duzula adierazten du. Adibidez, gakoaren hatz-marka irakurri diozu jabeari telefonoz.