Cryptanalysis

In cryptanalysis, a meaning which is already encoded in a form/construction is encoded again, because the original encoding of the meaning is opaque for the listener and/or speaker. Cryptanalysis is one of the four mechanisms of form-function reanalysis established by Croft (2000).

Example
Instances of cryptanalysis are often found with acronyms, where the original meanings of the individual letters are not clear to the speaker. Many speakers add to the form PIN (personal identification number) an additional 'number' cf. PIN-number, because the literal meaning of this acronym is not clear to them.

Reference

 * Croft, William. 2000. Explaining Language Change. An Evolutionary Perspective, ch. 5. Form-function reanalysis. Harlow: Longman, 117-144.