The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography

Besides the intolerable destruction of ships, there was also a terrible human cost-50,000 Allied seamen died during the war.

Before the overhaul of the postage system in the mid-1800s, sending a letter cost about a shilling for every hundred miles, beyond the means of most people. However, newspapers could be posted free of charge, and this provided a loophole for thrifty Victorians. Instead of writing and sending letters, people began to use pinpricks to spell out a mes

However, in addition to employing ciphers, the Arab scholars were also capable of destroying ciphers. They in fact invented cryptanalysis, the science of unscrambling a message without knowledge of the key.

Stuart Milner-Barry, one of the Hut 6 cryptanalysts, wrote: “I do not imagine that any war since classical times, if ever, has been fought in which one side read consistently the main military and naval intelligence of the other.”

Despite the combined efforts of the Association, amateur treasure hunters and professional cryptanalysts, the first and third Beale ciphers have remained a mystery for over a century, and the gold, silver and jewels have yet to be found.

Alice and Bob have agreed on a onetime pad, and the laws of quantum physics actually forbid Eve from successfully intercepting it.

The Swiss experiment with optic fibers demonstrates that it would be feasible to build a system that permits secure communication between financial institutions within a single city.

Secret communication achieved by hiding the existence of a message is known as steganography, derived from the Greek words steganos, meaning “covered,” and graphein, meaning “to write.”

Furthermore, quantum cryptography has an additional benefit: it provides a way for Alice and Bob to find out if Eve is eavesdropping. Eve’s presence on the line becomes apparent because every time that she measures a photon, she risks altering it, and these alterations become obvious to Alice and Bob.