Alan Turing puzzle

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Across
  1. 2. a person good at solving problems and calculations
  2. 4. the illness that made Christopher die
  3. 5. the catastophic historical event from 1939 to 1945
  4. 7. name Turing gave to his machine
Down
  1. 1. A highly toxic compound
  2. 3. a word game with a grid of white and black squares
  3. 6. person who secrtely gets confidential information