Classic Ciphers and Why They Fail
Encryption scrambles data with a key so only key holders can read it. Looking at old ciphers shows why modern ones are built the way they are.
The Caesar cipher shifts each letter a fixed number of places: with a shift of 3, A becomes D. There are only 25 possible keys, so an attacker simply tries them all, and the letter pattern (e is the commonest English letter) betrays it too.
Lesson: a secure cipher needs a huge key space and must hide patterns. Never invent your own cipher; use well-tested standard ones.
Why is the Caesar cipher easy to break?
Encrypt 'Attack at dawn' with a Caesar shift of 5 (keep spaces and capitals) and print the result.
Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.
Tip: use the left and right arrow keys to move between lessons.