I have qualms about key being used for the npub.

Key Etymology: “

> instrument for opening locks," Middle English keie, from Old English cæg "metal piece that works a lock, key" literal and figurative ("solution, explanation, one who or that which opens the way or explains"), a word of unknown origin, abnormal evolution, and no sure cognates other than Old Frisian kei.”

Key makes perfect sense for nsec.