Family Countersign · works offline · nothing leaves your phone
AI can fake a voice. It can't fake our secret.
Pair once, in person. From then on, both phones show the same three words, changing every minute. If someone calls sounding like family and asks for money, ask for the countersign.
Family Circle
One QR code for the whole family. Everyone scans it once, picks their name, and gets their own three words. Anyone in the circle can then check anyone else.
Two-person pairing (strongest)
For the people you talk to most. Each direction gets its own words, so even someone who tricks one of you can't relay them to the other.