GCHQ Christmas challenge: Agency reveals 2023 codebreaker

What do gift tags, candy canes, and complex codes have in common? They're all components of an annual brainteaser for UK school children, devised by the nation's intelligence agency. As the winter break approaches, GCHQ has released its code-breaking challenge, targeting students aged 11 to 18. Over 1,000 secondary schools have registered for the 2023 event, which features some of the most challenging puzzles to date.

This is the third iteration of the challenge, which is structured around a Christmas card sent by Anne Keast-Butler, the director of the Cheltenham-based intelligence agency. The card contains challenges designed to test skills such as codebreaking, mathematics, and analysis, with each task intended to be more difficult than the previous one.

One of the seemingly less demanding questions prompts students to categorize nine gift tags into three groups of three, with each group linked by a single word. Those three words are then connected by another word that can follow 'Christmas'. The challenge comprises seven questions in total, along with a mathematically-focused bonus puzzle, which is billed as the most difficult task included so far. Students are encouraged to tackle the challenge in teams, utilizing individual skills to decipher the code, but the public is also welcome to attempt the puzzles informally. This year's Christmas challenge adopts a more historical theme, featuring Bletchley Park, the wartime headquarters of the intelligence agency. The full challenge can be accessed on the GCHQ website.