Friday, November 05, 2010

Code Book Collection

Nick Gessler just published a beautiful collection of old military and civilian code books. He scanned all pages of each book and made them available as pdf files on his website.

The code books are dated between 1878 and 1947. There are several military field codes, Artillery codes, a 1941 Air-Ground Liaison code, but also civilian code books: Telegraph codes, railway codes, cotton trade codes and various merchant and phrase code books, Larabee cipher codes, an Imperial Combination Code, Inter-State cipher and pocket code books.

These are all code books in the true sense of the word code in cryptography: large substitution tables to convert words and phrases into letter groups or digits. Today, such code books would not stand a change against cryptanalysis. However, in the early days of communications they did provide some security and had another important benefit: they could reduced the length of a message considerably. In the 1800's and early 1900's, the often commercial electric telegraph (land lines) were virtually the only way to communicate over long-distance. Reducing the message length was a plus if a telegram was payed per word or per character.

Visit Nick's great Code Book collection and don't forget to check out his main page also, the Cryptology & Steganography Collections with many images of crypto hardware. Most of his code books are also available on the Internet Archive. John McVey has an extensive list of scanned code books.

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