Monoalphabetic Substitution client-side ?
How to use Monoalphabetic SubstitutionA monoalphabetic substitution replaces each letter of the alphabet with another, in a fixed way: the key is the replacement alphabet (26 letters). Set this key manually, generate it from a keyword, or shuffle it at random, then encrypt and decrypt. The solver mode helps you crack a cryptogram whose key you don't have: it shows the letter frequencies of the text and lets you propose mappings, with a live decryption preview that updates with every guess. It's the classic method to solve substitution puzzles. Everything is local in your browser.
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A monoalphabetic substitution replaces each letter of the alphabet with another, in a fixed way: the key is the replacement alphabet (26 letters). Set this key manually, generate it from a keyword, or shuffle it at random, then encrypt and decrypt. The solver mode helps you crack a cryptogram whose key you don't have: it shows the letter frequencies of the text and lets you propose mappings, with a live decryption preview that updates with every guess. It's the classic method to solve substitution puzzles. Everything is local in your browser.
Encrypt or crack a substitution cryptogram.
How to use Monoalphabetic Substitution
A monoalphabetic substitution replaces each letter of the alphabet with another, in a fixed way: the key is the replacement alphabet (26 letters). Set this key manually, generate it from a keyword, or shuffle it at random, then encrypt and decrypt. The solver mode helps you crack a cryptogram whose key you don't have: it shows the letter frequencies of the text and lets you propose mappings, with a live decryption preview that updates with every guess. It's the classic method to solve substitution puzzles. Everything is local in your browser.
Frequently asked questions
How do I crack a substitution without the key?
Use the solver mode with frequency analysis: the most frequent letter is often E, then T, A, O, I, N in English. Test mappings and read the preview until the text becomes readable.
How is it different from Caesar?
Caesar is a special substitution where the whole alphabet is shifted by the same amount. Here any letter can map to any other, giving far more possible keys (26! ≈ 4×10²⁶).