Spy agency's 'fun' quiz still not cracked
It cannot be solved with a search engine. Specially written algorithms have failed to crack it. Even geeks pooling their considerable resources in internet chat rooms have fallen short.
More than a month after the director of GCHQ set a fiendishly difficult "fun" Christmas quiz, not one person has managed to get all the answers right.
More than 600,000 people have attempted the task, from the west coast of America to our very own shores downunder, with 30,000 reaching the end and submitting entries via the GCHQ website.
They range from a 14-year-old maths prodigy to retired professors. But all have been found wanting.
READ MORE: Can you solve UK spies' puzzle?
With just four days to go until the deadline for entries expires, it seems that the cryptographers have stumped the entire planet with what may go down as the world's hardest puzzle.
"We have had entries that have been within one or two answers of being perfect," said a spokesman for Government Communications Headquarters, to use its full title, "but no one has quite got there yet".
Part of the problem lies in the fact that some questions are so open-ended that puzzlers do not know whether they have answered the question in full.
Some questions, in the form of pictograms, do not even have instructions for what is required.
GCHQ insists the quiz is not impossible, though it admits that its top cryptographers who set the questions have made some of the solutions so abstract that players might not follow the same train of thought.
"There are solutions which are not immediately apparent," said the spokesman. "You don't necessarily know if you have got all the answers or if there is something you have missed."
GCHQ will not even say what the perfect score is, as that would be a clue in itself.
The puzzle is formed of five sections, the first of which is a crossword-style nonogram that, when filled in, forms a Quick Response code that can be scanned with a mobile phone to access the second part of the quiz via a website.
Each section must then be completed before access is granted to the next, increasingly harder, stage.
Not everyone who submitted entries understood this concept.
"We had people who sent in a hard copy of the nonogram saying they had done it, but couldn't work out what the picture was meant to be," said the spokesman.
Even computer programmers who have written their own algorithms to solve each section of the puzzle have been unable to fathom all its subtleties.
The quiz was originally intended as a private challenge to the 1000 people who receive a Christmas card from Robert Hannigan, director of GCHQ, but the agency decided it deserved a wider audience.
Hannigan, who has asked players to donate to the NSPCC as a goodwill gesture, has offered one final clue: "It's not as abstract as you think."
The prize for the winner will not be a job at GCHQ, though the agency hopes the quiz will stimulate interest.
Hannigan's spokesman said: "He's thinking in terms of a signed book and maybe a GCHQ paperweight."
The closing date for entries is midnight on Sunday.
Feeling lucky? Visit http://tinyurl.com/gchqquiz to start your quest.
- The Telegraph, London