He wrote a trilogy of books called Military Cryptanalytics covering code breaking in 1977 ... with some examples of hard-to-solve crypto puzzles. One key part of the book, apparently, is ...

Soon after her officer training in Washington, she was recruited to a classified code-breaking team. She kept her work secret ...

The key to unlocking the puzzle is identifying Samuel, Louis and Ludwik. In this case, we need to find a common link between them. They are all pioneers in the world of language and code ...

These people were good with languages, crossword puzzles, chess ... Your supervisors were so happy with your code-breaking skills that they've assigned you to break this new message that has ...

CLUE: The key to unlocking the puzzle is identifying Samuel ... you can join the social media conversation on the GCHQ code-breaker challenge using hashtag #GCHQpuzzlebook.