Statistical Cryptanalysis
Cipher Detective
Paste unknown ciphertext and the Detective will walk you through the evidence — letter frequencies, Index of Coincidence, chi-square analysis, Kasiski examination — and show which cipher families best fit the data.
Awaiting input. The Detective analyses text as you type or paste.
Insufficient evidence. This text is too short for reliable
statistical analysis. The suspects below are best guesses, not confident
identifications. Paste a longer sample if available.
Evidence
Suspects
Case Notes
Recommended Next Attack
🔒 Auto-Solve (Advanced)
Run every applicable solver against this ciphertext and rank the results by how English-like each candidate plaintext is. Works on Caesar, ROT13, Atbash, Vigenère, monoalphabetic substitution and columnar transposition. May take a few seconds for substitution.
What the Detective can’t tell you
- Short ciphertext (under ~60 characters) makes statistical analysis unreliable.
- Non-English plaintext breaks all English-based frequency analysis.
- Modern ciphers (AES, ChaCha20) produce statistically random output; the Detective will report “random” but cannot identify which modern cipher.
- Layered ciphers (VIC, Purple, multi-stage) defeat single-pass identification.
- The Detective’s Auto-Solve can recover plaintext for Caesar, ROT13, Atbash, Vigenère, monoalphabetic substitution, and columnar transposition. For richer hand-tools and other ciphers, open the Codebreaker’s Workbench.