Tech WondersPlay

Codes, Cryptography & BlockchainCryptography

The Secret Handshake

Two strangers can agree on a secret while everyone listens

Two strangers shout across a crowded room and end up sharing a secret nobody else knows. Impossible? Your phone does it all day.

You'll find out

  • What paint has to do with secret keys
  • Why hearing everything isn't enough
  • The math behind your browser's padlock

Why it matters

It quietly guards almost every secure connection you make, from banking apps to private chats.

About 4 min7 interactive slides · 5 questionsLesson 33 · Zone 4

Play this lesson

Free to play in your browser or on iPhone

More in this zone

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  2. 29Account SecurityTwo-Factor LoginA stolen password is nearly useless without the second key
  3. 30Classical CryptographyCaesar's CipherJulius Caesar hid messages by shifting every letter three places
  4. 31CodebreakingCounting Letters Breaks CodesA 9th-century scholar cracked substitution ciphers with a tally chart
  5. 32Classical CryptographyThe Unbreakable Cipher That BrokeVigenère's code was called indecipherable for 300 years
  6. 34Quantum PhysicsThe Quantum TunnelParticles can cross walls they can't climb, and your phone's memory relies on it
  7. 35Energy StorageWhy Your Battery Wears OutHeat, full charges and empty batteries age your phone fastest
  8. 36Data StorageWhy Your 1 TB Drive Shows 931 GBDrive makers and computers count bytes differently