Cable/Telegraph Codes
The substitution ciphers we have looked at can encrypt any message, even words or names unknown at the time a cipher was devised. True codes, on the other hand, are a closed system – when people are assigned new labels (Gazelam for “Joseph Smith,” for instance), you cannot introduce a new name without notifying correspondents of the additional code word.
Nineteenth century Mormon leaders used true codes following the completion of the telegraph, and especially following the completion of the transatlantic cable. Cable codes could be used to maintain secrecy, but generally they were intended to lower the expense of cabling between, say, Liverpool and Salt Lake City, because a single code word could replace the multi-word name of a person or city, or signal the completion of an assignment.