Correct spelling


Correct spelling, explanation: the word is constructed by using and prefix de-, meaning to undo something, and the base word cipher or cypher. In fact, both forms are correct, but the form cipher is a much more preferred spelling, which is why it’s used in derivations of the word – such as decipher.

Definition of decipher:
1. to unveil the meaning of an encrypted message
My handwriting is so bad that when anyone reads it they have to decypher it like a code.
Enigma is historically one of the most popular machines to decipher codes.

Incorrect spelling


Incorrect spelling, explanation: decypher is an incorrect word, but mostly because of the preferences in spelling between cypher and cipher. In general, the spelling with i is a preferred option, because it’s more closely related to the pronunciation and it better represents the ai dyphtong in pronunciation, and because of that decipher is considered to be the correct spelling.