Sublime

British planes would lay mines in a particular location, provoking German vessels to send out warnings to other craft. These Enigma encrypted warnings would inevitably contain a map reference, but crucially this map reference would already be known by the British, so it could be used as a crib.

In fact, Britain had captured thousands of Enigma machines, and distributed them among its former colonies, who believed that the cipher was as secure as it had seemed to the Germans. The British did nothing to disabuse them of this belief, and routinely deciphered their secret communications in the years that followed.

The Ultra achievement owed much to three Polish mathematicians, led by Marian Rejewski, who conducted critical early work on the German Enigma code machine between 1932 and 1939, after acquiring a commercial example of the ciphering device.

A nomenclator is a system of encryption that relies on a cipher alphabet, which is used to encrypt the majority of a message, and a limited list of codewords.

enigma