iCryptograms · Cryptogram Decoder
Paste a cryptoquote and watch it crack. Lock the letters you're sure of, clear the ones you aren't, and the rest re-solves around them.
Cipher → plain
Click any letter, then type its real letter to lock it (A–Z). Space locks or unlocks · ← → move · Backspace clears.
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Paste any substitution cipher and the engine breaks it in your browser, usually in under a second. Nothing is uploaded: the puzzle never leaves your machine.
It runs a word-pattern dictionary attack. Every word in the ciphertext is reduced to its repeat signature — THAT becomes 1-2-3-1 — and matched against a dictionary indexed by that same signature. Candidate words are then propagated as constraints: choosing a match for one word forces letters in every other word, and contradictions are pruned immediately. The solver picks the most-constrained word first, which collapses the search space fast.
When a puzzle contains words the dictionary does not know — proper nouns, invented words, or no spaces at all — the solver falls back to statistical hill-climbing against a quadgram model of English, mutating the cipher key until the plaintext stops looking like letter soup.
Very short ciphers are genuinely ambiguous: with only twenty or thirty letters, several different English sentences may fit the same pattern, and no solver can tell you which one the author meant. That is not a bug in the machine; it is a property of the cipher.
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