Editing Book cipher (section)

== Using widely available publications ==

=== Dictionary ===
Another approach is to use a dictionary as the codebook. This guarantees that nearly all words will be found, and also makes it much easier to find a word when encoding. This approach was used by [[George Scovell]] for the [[Arthur Wellesley, 1st Duke of Wellington|Duke of Wellington]]'s army in  some campaigns of the [[Peninsular War]]. In Scovell's method, a codeword would consist of a number (indicating the page of the dictionary), a letter (indicating the column on the page), and finally a number indicating which entry of the column was meant. However, this approach also has a disadvantage: because entries are arranged in alphabetical order, so are the code numbers. This can give strong hints to the [[cryptanalysis|cryptanalyst]] unless the message is [[code (cryptography)#Superencipherment|superenciphered]]. The wide distribution and availability of dictionaries also present a problem; it is likely that anyone trying to break such a code is also in possession of the dictionary which can be used to read the message.

=== Bible cipher ===
The [[Bible]] is a widely available book that is almost always printed with chapter and verse markings making it easy to find a specific string of text within it, making it particularly useful for this purpose; the widespread availability of [[bible concordance|concordances]] can ease the encoding process as well.