Ciphers and secret messages

What is a Cipher?

100

What is a Cipher?

A way of changing letters into numbers or symbols to keep a message secret.

200

Why do people use ciphers?

To keep information secret.

300

Is a cipher always numbers?

No, it can be numbers, symbols, or letters.

Encoding (Letters → Numbers)

100

Encode CAT

3 1 20

200

Encode DOG

4 15 7

300

Encode SUN

19 21 14

Decoding (Numbers → Letters)

100

Decode 1 2

AB

200

Decode 8 5 12 12 15

HELLO

300

Decode 19 21 14

SUN

Code Knowledge (A=1 to Z=26)

100

What number is A?

1

200

What number is M?

13

300

What number is Z?

26

Challenge Round

100

What is harder: encoding or decoding? (Explain)

To encode means to change letters into numbers.

To decode means to change numbers back into letters.

200

What does 4 1 25 spell?

DAY

300

Encode “I AM HAPPY”

9 1 13 8 1 16 16 25 (spaces ignored)