Classroom mode

Run it in class

Can two friends build the same hidden number while a listener copies every public card?

Show of hands — before you project anything

Why is the modulo-17 clock useful for learning even though it is not a security recommendation?

  • A Way more than you'd guess
  • B About what you'd guess
  • C Way less than you'd guess

Count the votes out loud. Hold them to it — then watch.

Project it (fullscreen)

Discussion prompts

  • Why is the modulo-17 clock useful for learning even though it is not a security recommendation?
  • What is different about a passive listener and an active middle party?
  • Why do approved group structure and parameter size both matter?

Where it shows up in real life

  • A browser and website establishing fresh session keys
  • A messaging protocol agreeing on ephemeral keys
  • Secure tunnels that authenticate peers before carrying private traffic

A prediction-first worksheet — no answer key.

zero prep · no login · any projector

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