Symbol Substitution

Letters are replaced with symbols according to a given key.

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Letters are replaced with symbols according to a given key.

Symbol substitution codes replace letters with symbols (@, #, $, %, etc.) according to a provided key. Unlike alphabetic shifts, there's no predictable pattern—you must use the key exactly as given. The key may only cover some letters, with others following a different rule.

A=@, B=#, C=$, etc. (as specified in key)

If A=@, B=#, C=$ then ABC = @#$
If X=!, Y=?, Z=* then XYZ = !?*
Decode #@$ using A=@, B=#, C=$ → BAC

How to recognize it

Message contains symbols not normally in words
A key is provided mapping letters to symbols
No predictable pattern—must use the key

Common mistakes

Trying to find a pattern instead of using the key
Confusing similar-looking symbols
Misreading which symbol maps to which letter

Step-by-step walkthrough

Decode '#@$' using the key: A=@, B=#, C=$

Look up # in the key: B=#, so # = B
Look up @ in the key: A=@, so @ = A
Look up $ in the key: C=$, so $ = C

Answer: BAC

Practice guidance

Coding & Decoding