BLETCHLEY, ENGLAND - JUNE 03: Valves on the Colossus computer, used during World War II to decypher German code at Block H, Bletchley Park pictured at The National Museum of Computing on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)

BLETCHLEY, ENGLAND - JUNE 03: Former "Wren" - a member of the Women's Royal Naval Service and codebreaker at Bletchley Park, Lorna Cockayne inspects a slip of undulator tape used in codebreaking during World War II at The National Museum of Computing on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)

BLETCHLEY, ENGLAND - JUNE 03: Former "Wrens" - members of the Women's Royal Naval Service and codebreakers at Bletchley Park, (Front row R-L) Lorna Cockayne, Irene Dixon, Shirley Wheeldon, Margaret Mortimer and Joanna Chorley inspect a slip of undulator tape used in codebreaking during World War II at The National Museum of Computing on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)

BLETCHLEY, ENGLAND - JUNE 03: Former "Wren" (a member of the Women's Royal Naval Service) and codebreaker at Bletchley Park Irene Dixon pictured at The National Museum of Computing on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)

BLETCHLEY, ENGLAND - JUNE 03: Former "Wren" (a member of the Women's Royal Naval Service) and codebreaker at Bletchley Park Irene Dixon pictured at The National Museum of Computing on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)

BLETCHLEY, ENGLAND - JUNE 03: A general view of The National Museum of Computing, formerly known as Block H during World War II, Bletchley Park on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)

BLETCHLEY, ENGLAND - JUNE 03: A general view of The National Museum of Computing, formerly known as Block H during World War II, Bletchley Park on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)

BLETCHLEY, ENGLAND - JUNE 03: The Lorenz SZ42 German cypher machine pictured at The National Museum of Computing on June 3, 2016 in Bletchley, England. During World War II British codebreakers helped decypher the German Army's Lorenz cypher using the Colossus computer and Tunny machine at the Government Code and Cypher School's (GC&CS) main codebreaking centre, Bletchley Park. The machines at Bletchley Park's Block H, the world's first purpose-built computer centre, helped gather crucial intelligence for the British military during the war. (Photo by Jack Taylor/Getty Images)