Secret Messages Basics
📋 What it is
A code hides a message so only someone who knows the rule (the key) can read it.
🗣️ Coach says
Cryptography is the art of secret messages. You SCRAMBLE a message with a rule, and only someone with the KEY can unscramble it. Two words to know: encrypt (lock it) and decrypt (unlock it).
🧠 Memory hook
Encrypt = lock the message. Decrypt = unlock it. The key is the secret rule.
😂 Giggle
Why did the spy fail the math test?
Because all the answers were in code!
😲 Whoa!
People have hidden messages for thousands of years — ancient Greeks tattooed a message on a messenger’s shaved head, let the hair grow back, then shaved it again to read it.
✅ Quick check: What’s the difference between “encrypt” and “decrypt”?
Say your answer out loud first — then reveal.
Encrypt = scramble/lock the message with the rule; decrypt = unscramble/unlock it using the key.
Encryption hides the message; decryption recovers it with the key.
🧪 Try it! (2 minutes)
Invent a simple rule (swap A↔Z, B↔Y…) and send a friend a one-word secret. Can they decrypt it?