Some other languages, e.g., Polish, tend to do the opposite and refer to both principal types of cryptography as 'cipher', as in ' Biuro Szyfrów' ('Cipher Bureau').

^ In contemporary English-language jargon, the word 'code' is often used for any sort of secret communication, whether or not that communication is actually performed using a code in the strict sense.

The book is not footnoted but has a 'Further Reading' section at the end, organized by chapter. The book announced a 'cipher challenge' of a series of ten progressively harder ciphers, with a cash prize of £10,000, which has since been won.

The book concludes with a discussion of ' Pretty Good Privacy' (PGP), quantum computing, and quantum cryptography.

Some of this material is based on interviews with participants, including persons who worked in secret at GCHQ. Later sections cover the development of public-key cryptography. The Code Book covers diverse historical topics including the Man in the Iron Mask, Arabic cryptography, Charles Babbage, the mechanisation of cryptography, the Enigma machine, and the decryption of Linear B and other ancient writing systems. Thus the book's title should not be misconstrued as suggesting that the book deals only with codes, and not with ciphers or that the book is in fact a codebook. The Code Book describes some illustrative highlights in the history of cryptography, drawn from both of its principal branches, codes and ciphers.

The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography is a book by Simon Singh, published in 1999 by Fourth Estate and Doubleday.

The code book by simon singh