For Educators · Classical Ciphers
Classical Ciphers for a MAC tag
Built for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs. Simulate a MAC tag 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 educators?
- Yes — this version of "Classical Ciphers for a MAC tag" is framed for educators teaching it to a class. Drop a live demo into a lecture or assign it as a shareable link — no lab installs.
- Do I need to install anything?
- No. It runs in any modern browser, free, with no account required.