Sending one instead? Open the web app → (needs your Google sign-in)
Make up a passcode, hand it over, and type the phrase they gave you beforehand. Why two?
The passcode is minted here and travels to them; the phrase was agreed between you beforehand and is never sent. A portal needs both, so whoever catches the passcode on its way has one half of two. Nothing flows back to them — a portal is a window, not a conversation.