For Students · Classical Ciphers
Classical Ciphers for a key exchange
Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate a key exchange live below — adjust the inputs and watch it respond, right in your browser.
Classical CiphersLive
Caesar & Vigenère
plaintext
ATTACK AT DAWN
↓ encrypt
ciphertext
DWWDFN DW GDZQ
Controls
Presets
The Caesar cipher shifts every letter by a fixed amount — trivially broken by trying all 25 shifts or by letter-frequency analysis. The Vigenère cipher uses a repeating keyword so each letter shifts differently, defeating simple frequency attacks for centuries until the key length could be found. Both are insecure today but perfect for learning how ciphers work.
Data Inspector
CipherCaesar +3
Keyspace26
Letters12
Governing equation
Reading this result: Every letter shifts by the same 3, so this Caesar cipher's 25-key space is cracked instantly by trying all shifts or by letter-frequency analysis.
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Frequently asked questions
- Is this good for students?
- Yes — this version of "Classical Ciphers for a key exchange" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
- Do I need to install anything?
- No. It runs in any modern browser, free, with no account required.