🔑 How Does It Know It Is You?
Three ways a computer checks who you are, and why one is not enough.
🔥 Warm Up — 2 minutes
Ask: “If I phoned you and said I was your cousin, how would you know it was really them?” Let them come up with tests.
“Computers have exactly the same problem, and only three ways to solve it.”
🤖 The Activity — 15 minutes
Write three headings on paper: Know · Have · Are.
Now sort things into them together. A password? Know. A phone that gets a code? Have. A fingerprint? Are. A face? Are. A secret handshake? Know. A key? Have.
Then ask, for each one: “How could someone steal this?” A password can be guessed or told. A phone can be taken. A face is harder — but a photograph of a face is not.
🧩 The Twist — 5 minutes
Ask your child to invent a way to prove they are them using two of the three. Then try to break it.
This is exactly what a bank does, and exactly why it asks for a password and a code.
Identity Badge
Learned the three kinds of proof and why two beat one
Parent Notes — tap to expand
▼The three authentication factors, and that security comes from combining categories rather than from making any single one longer or cleverer.
- Which of the three is easiest for someone to steal?
- Why does a code sent to a phone help, if someone already knows the password?
- Is a photo of your face the same as your face?
Children often suggest “a really long password” as the answer. The useful correction is that a second category beats a longer version of the same one.
Say this out loud and make them repeat it: a code that arrives on a phone is never, ever read out to anyone. Not to a bank, not to a delivery person, not to someone who says there is a problem. Nobody real ever asks.