Editing Secret decoder ring (section)

{{short description|Device for decoding a substitution cipher}}
[[File:Captain-midnight-decoder.jpg|thumb|A [[Captain Midnight]] decoder badge]]

A '''secret decoder ring''' (or '''secret decoder''') is a device that allows one to decode a simple [[substitution cipher]]—or to encrypt a message by working in the opposite direction.<ref>{{Citation
 | last = Hipschman
 | first = Ron
 | title = The Secret Language
 | year = 1995
 | url = http://www.exploratorium.edu/ronh/secret/secret.html
 | accessdate = 2011-01-10}}</ref>

As inexpensive toys, secret decoders have often been used as promotional items by retailers, as well as radio and television programs, from the 1930s through to the current day.
Decoders, whether badges or rings, are an entertaining way for children to tap into a common fascination with [[encryption]], [[cipher]]s, and [[Cryptography|secret codes]], and are used to send hidden messages back and forth to one another.