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🔐 Caesar / Vigenère Cipher

Caesar and Vigenère cipher encrypt/decrypt with brute-force, crib filtering, chi-squared ranking, frequency analysis, IC, Kasiski auto-crack, and Tabula Recta

All encryption and decryption runs locally in your browser — input data is not uploaded by the tool.
Cipher Type
Direction
▶ Frequency Analysis
Enter text to see letter frequency distribution.
▶ Tabula Recta (Vigenère Square)

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Free online Caesar and Vigenère cipher tool — two classic ciphers in one. Caesar cipher with 0-25 shift slider, ROT1/3/5/13/18/25 presets, and brute-force attack with chi-squared ranking and crib (known plaintext) filtering. Vigenère cipher with alphabetic key encryption/decryption and auto-crack (Kasiski examination + IC key length detection + frequency analysis key recovery), client-side. Built-in frequency analysis bar chart with English standard comparison, Index of Coincidence (IC), and Tabula Recta (Vigenère Square). Real-time 200ms response. Perfect for learning cryptography, CTF competitions, and developers.