In 1811 George Scovell was given a book: ‘Cryptographia, or The Art of Decyphering’ by David Arnold Conradus. It contains a series of rules and principles for creating and breaking codes and ciphers. It also provides sample problems and instructions for dealing with ciphers in English, German, Dutch, Latin, French and Italian.

Scovell experimented with different encryption methods based on the principles in ‘Cryptographia ‘. He devised a method of ensuring that the British had a common cipher to protect their dispatches by sending copies of the same dictionary to each headquarters. By his system, 56C2 would direct the reader to page 56, column C and the second word down. Although simple, this was a strong and successful code.