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Wednesday, Nov 19, 2025

GCHQ's 2023 Christmas Codebreaker Challenge

The UK's spy agency, GCHQ, has launched its 2023 Christmas codebreaker challenge for schoolchildren aged 11 to 18, incorporating elements like gift tags and candy canes into its complex puzzles.
Over 1,000 secondary schools are participating in the event, which includes some of the hardest puzzles to date.

The initiative, now in its third year, features a Christmas card from GCHQ director Anne Keast-Butler, with escalating levels of difficulty across various challenges focused on codebreaking, mathematics, and analytical skills.

One of the simpler puzzles invites students to categorize nine gift tags into three linked groups, while another, tailored for those with a numerical bent, involves solving a cryptic equation, both with connections to the word 'Christmas'.

In addition to the main seven riddles, there's a bonus math problem considered the most challenging yet. While students are encouraged to work in teams to solve the puzzles, the public can also attempt them informally.

Spearheaded by chief puzzler Colin, the agency highlights the value of diverse thinking, drawing parallels to GCHQ's own problem-solving approach.

This year's theme traces historical roots, spotlighting Bletchley Park, the WWII code-breaking hub, and referencing its recent hosting of the AI Safety Summit. The challenges embrace GCHQ's longstanding encryption expertise, celebrating their heritage and ongoing mission to protect the nation.
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