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Rules, Regulations & Policies

You can download our GDPR Compliance Statements here.

Please read on to find out about our data policy and rules and regulations for the 2020 special edition of the competition.

Cookies on the site

  1. We use cookies to anonymously track usage of the website through Google Analytics. No personally identifiable information is recorded by Google Analytics’ cookies.
  2. We also use cookies to keep track of users’ activities when they login in order to facilitate the core functions of the site. We don’t request more information from you when registering for an account than is necessary to administer the competition. If you have any questions or concerns about this or any aspect of data security on this site then please do contact us at [email protected].

You can read more about this on our Cookie Policy page.


We endeavour to provide an accessible challenge website to those using assistive technologies. We have further information in our Accessibility Statement and welcome your feedback of any accessibility issues you may encounter.

Your data

  1. We collect data about you solely for use in connection with the competition.
  2. We will only share that data with those who need it in order to administer the competition. This includes the competition staff at the University of Southampton and a small number of staff in the website development team and they are only permitted to use that data in connection with the competition.
  3. With the exception of the Leader Boards and material you post on the Forum, if any, we will not share your data with anyone else without your consent. Submitting an entry to the competition or posting on the forum is taken to imply informed consent to the publication of relevant material.
  4. Prize winners are required to consent to publication on the website of:  the names of winning team members, their team name and their school affiliation(s) (if any) as a condition of accepting the prize.
  5. We will delete your data on request, submitted in writing or by email to [email protected]

Who can take part?

  1. The competition is open to anyone but only individuals in full time school level education in the UK qualify for prizes.
  2. 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 leader board.

Submitting your solutions

    1. Each challenge round consists of two parts, part A and part B each with its own entry form. Entries must be submitted on the correct form for each part of the challenge.
    2. Only designated Team Captains, or those with the Team Captain account login, can submit answers for a 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 correct 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.
    7. Any “mistake” in the text might be deliberate, so  don’t try to correct any errors you think we have made. Always type in an exact decryption of the text, otherwise you risk losing points when it is compared to our solution.
    8. Don’t try to tell us what cipher we used, or to ask us a question, or to say how you solved the cipher in the entry form, we don’t read it and it will be marked as an error in the solution.
    9. Do not include any headers like Challenge 1A or the title in your solution as these will also be marked as an error.
    10. If you do make a mistake you can resubmit using the usual submission box on the Challenge page, but be careful not to abuse this (see 3 above on rapid fire submissions).
    11. Check for feedback in your account area under will sometimes be a bit delayed but will at least appear after the next Part B points deadline, which you can find listed on the current Challenge page under the Deadlines link.

Scoring the challenge

  1. For each of the challenges 1 to 7 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. For those of you who like this sort of thing (which is, it seems, perhaps unsurprisingly, quite a few of the Cipher Challenge officianados) accuracy will be measured using the Damerau-Levenshtein metric. Time points will be based on a schedule published alongside the challenge. Accuracy is more important than speed, so we will use the lexicographic order on the pairs (accuracy, speed) to determine your position on the leaderboard.
  2. The scores for Challenges 3B, 4B, 5B, 6B, 7B,  will be aggregated to determine the Championship Leaderboard.
  3. 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.

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 is practical.
  2. The Challenge Committee may publish clues on the competition web-site if it considers it appropriate to do so.


  1. Anyone posting a solution or partial solution in any public forum before the deadline for the given Challenge will be spoiling the competition for others. Please do not publish hints without checking with us first! We reserve thee right to disqualify anyone breaking this rule.