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Cipher guide

Substitution cipher

In a substitution cipher, each coded letter always stands for one real letter. The full coded alphabet can be mixed in any order.

See a simple example

Imagine that coded Q means E and coded X means T. The code QXXQ becomes ETTE. The first and last letters match, and the two middle letters match. That shape is a useful clue.

Try it step by step

Start with repeated letters, one-letter words and common short words. Common letters can help, but they do not prove an answer. Add each strong match to the full message and check that nothing breaks.

Watch out for these mistakes

Do not use the same coded letter for two real letters. Do not trust a guess after it breaks another word. Short messages can also have unusual letter counts.

Try it in Seven Worlds

The game gives you an A to Z letter pad and shows every change in the message. This makes it easy to test a match and take it back if it is wrong.

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