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Who can take part?

  1. The competition is only open to persons aged 18 or under on 31 August 2017.
  2. Only entrants from the UK who are in full time school-level education in the United Kingdom, the Channel Islands and the Isle of Man are eligible for prizes.  (For the sake of clarity, home-schoolers in these ulesegions do qualify). If you don’t qualify for this or age reasons please tick the “ineligible for prizes ” box when you register, it saves embarrassment!)
  3. Entries may be received from individuals or from teams. The teams may be of any size, but we reserve the right to restrict the number of team members listed on the honours board. Team Captains set the team name in their account.
  4. Teams must be set up by a Team Captain who we may contact via email and must provide details of a teacher we can contact if necessary.
  5. In order to qualify for any of the prizes, all entrants, whether solo or part of a team agree to their team and school names being used in publicity associated with the competition including publication on the competition web-site. We will publish team member names only with your permission.

Submitting your solutions

  1. Each challenge consists of two parts, part A and part B. You may submit solutions to either or both parts of the current challenge on the entry form.
  2. Only Team Captains, or those with the Team Captain account login, can submit answers for the team.
  3. Rapid fire multiple submissions put an unreasonable load on the servers and make it difficult for others to submit. Anyone who makes an unreasonable number of submissions will be open to disqualification. In the first instance this will mean that anyone who submits more than 20 times in 10 minutes will be disqualified.
  4. A submission will only be deemed to be valid if it is submitted on the entry form and all the instructions on this site are adhered to.
  5. In submitting an entry solo entrants vouch that it is solely their own work and teams warrant that it is solely their own collective work.
  6. In submitting an entry to the competition, all entrants, whether individuals or members of a team, agree to be bound by all the rules of the competition.

Scoring the challenge

  1. For each of the challenges 1 to 8 for which you submit an entry for part B you will be awarded a score, based on the accuracy of your best submission for that challenge and the order in which we receive the submissions. The scores will be used to determine your position on the leaderboard. The scores for Challenges 3B, 4B, 5B, 6B, 7B and 8B will be aggregated to determine the Championship Leaderboard and to decide on the winners of the main prizes, who will be chosen from among those achieving the highest total scores.
  2. A solution will only be deemed to be correct if, disregarding the punctuation [and spacing], the deciphered plaintext (only involving the Roman characters A to Z is letter perfect as compared to our master solution. UPPER or lower case solutions will be treated the same.


  1. Winners will be notified by email and will be announced on the website. Please ensure that our messages to you are not filtered by your spam filters by adding our email address [email protected] to your address book.
  2. The competition will be judged by the Challenge Committee, whose decision will be final in all matters regarding the competition including the award of prizes. We reserve the right to take into account the methods of solution in judging the final winners, and may ask potential winners for a brief description of their methods and a copy of any programmes they wrote when making the final decision.

Variations in the rules

  1. The organisers reserve the right to change any aspect of the competition at short notice and to split prizes where it is deemed appropriate. Such changes will be announced on the competition web-site as soon as practical.
  2. The Challenge Committee may publish clues on the competition web-site if it considers it appropriate to do so.
  3. If a correct solution of a challenge is not received before the deadline given on the schedule the Challenge Committee will have the discretion to not award the prize or award some or all of it to the entrant or entrants whom it judges to represent the best solution or solutions.


  1. Anyone posting a solution or partial solution in any public forum before the deadline for the given Challenge will be disqualified and barred from the forums. Please do not publish hints without checking with us first as this may spoil the competition for others.
  2. Entrants who do not abide by the rules will be disqualified from the competition and will not qualify for any of the prizes.