Able Seaman Colin Grazier, GC was posthumously awarded what, for "bravery and steadfast devotion to duty", he displayed on 30 October 1942 in action in the eastern Mediterranean when capturing codebooks vital for the breaking of the German naval "Shark" Enigma cipher from the sinking, the Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-20th century to protect commercial, diplomatic and military communication?
George Cross
Title: Enigma machine
Passage: The Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-20th century to protect commercial, diplomatic and military communication.  Enigma was invented by the German engineer Arthur Scherbius at the end of World War I.  Early models were used commercially from the early 1920s, and adopted by military and government services of several countries, most notably Nazi Germany before and during World War II.  Several different Enigma models were produced, but the German military models, having a plugboard, were the most complex.  Japanese and Italian models were also in use.
Title: Colin Grazier
Passage: Able Seaman Colin Grazier, GC was posthumously awarded the George Cross for the "outstanding bravery and steadfast devotion to duty in the face of danger" which he displayed on 30 October 1942 in action in the eastern Mediterranean when capturing codebooks vital for the breaking of the German naval "Shark" Enigma cipher from the sinking  .
Title: Polish Enigma double
Passage: A Polish Enigma "double" was a machine produced by the Polish Cipher Bureau that replicated the German Enigma rotor cipher machine.  The Enigma double was one result of Marian Rejewski's remarkable achievement of determining the wiring of the Enigma's rotors and reflectors.
Enigma machine Colin Grazier