Transposition Ciphers
📋 What it is
A transposition cipher keeps the letters but rearranges their ORDER by a rule (unlike substitution, which swaps letters).
🗣️ Coach says
Substitution changes WHICH letters; transposition changes their ORDER. Write “HELLO” down columns of a grid and read across, and you’ve rearranged it. Same letters, new order — reverse the rearrangement to decode.
🧠 Memory hook
Transposition scrambles the ORDER, not the letters. Reverse the rearrangement.
😂 Giggle
What's a cryptographer's favorite snack?
Crack-ers!
😲 Whoa!
The ancient Spartans used a transposition cipher with a rod called a “scytale” — you wrapped a strip of leather around a rod of the right thickness to line the letters back up.
✅ Quick check: How is a transposition cipher different from a substitution cipher?
Say your answer out loud first — then reveal.
Transposition keeps the same letters but changes their ORDER; substitution swaps each letter for a different one.
One rearranges positions; the other replaces symbols.
🧪 Try it! (2 minutes)
Write a 6-letter word in a 2×3 grid by rows, then read it by columns. That’s a transposition!