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Proposed Release Schedule for New Problems

All dates/times are showing for Europe/London timezone.

  • Problem 478: Saturday, 30th August 2014, 07:00 pm
  • Problem 479: Saturday, 6th September 2014, 10:00 pm
  • Problem 481: Sunday, 21st September 2014, 04:00 am

Recent News

18 August 2014: Publication of new problems

We're glad to announce that new problems are going to be published again.
Problems 477 and 478 were originally planned for June 2014.
Problem 477 will now be published Sat, 23 August, 16:00 (server time)
Problem 478 will be published Sat, 30 August, 19:00 (server time)

17 August 2014: Update (Project Euler Returns)

Since the return of Project Euler it seems that everything has gone well. As expected, some minor glitches were reported, but they have all been fixed. I would like to thank the members who took the time to report them.

It is worth pointing out that one of those glitches related to password checking and a small number of members were unable to sign in using their old passwords. This bug has now been fixed so if you tried to sign in yesterday and were unable to then it is quite possible you were a victim of this bug and you should try again.

In addition, the number of requests for password resets from members who have solved 200+ problems was very small and almost all of those were victims of the password checking bug. As a result, from today the threshold is being lowered to 100+ problems. Obviously by increasing the number members eligible also increases the potential number of requests, so if you make a request (link found on the Sign In page) then please be patient as each request is handled manually.

14 August 2014: Project Euler Returns

It is with the greatest of pleasure that the team can officially announce the return of Project Euler. The current website will go offline for a short period on Saturday 16 August 2014 at approximately 9am [BST] to restore full functionality.

The new site should look very familiar, but you can be assured that there has been a complete rewrite of the website engine. Along with such big changes it is quite possible that members will encounter teething issues as, hopefully only, minor bugs will be discovered. We would ask that anyone who spots any problems to report them to the forum:

Although full functionality will be restored: sign in/out, tracking which problems have been solved, access to the discussion threads, progression through levels, awards, and statistics, there is one significant change which we must make you aware of. After much discussion and consideration a decision has been made to no longer store email addresses. For a number of members this will not be a problem, as they had already used disposable email addresses to register, but for others this could have one major consequence: Account recovery will no longer be possible. With respect to this issue it is quite possible that some members will have genuinely forgotten passwords. There will be a link on the sign-in page which will outline the process for account recovery, but please be aware that initially this will only be available to members who have solved 200+ problems. The process will be handled manually so depending on the volume of requests the service will either be halted or we may move the threshold down from 200 problems.

The decision to no longer store any private/personal information in no way reflects a lack in confidence of the steps we have taken to make the new website secure, but if history teaches us one thing it is that for every "unsinkable" Titanic built there will always be icebergs. We hope you understand our reasons for this decision and accept that it was not made lightly. However, we would prefer to focus on the good news, which is the imminent return of Project Euler. We apologise for the long delay in restoring the website and we appreciate the patience shown by our members, but understandably the rewrite was no small undertaking.

You should also be aware that once you have successfully signed in you will be asked to change your password before you can do anything else.

Finally, we would like to thank you everyone for the positive and supportive comments made during the challenging time we faced whilst being offline.

27 June 2014: Answer Checking Restored

We are pleased to let you know that answer checking has now been restored to the website.

22 June 2014: Security Breach Update

As many of you will be aware it was discovered on Sunday 15 June 2014 that Project Euler had been hacked. An immediate decision was made by the team to take the website offline and to make everyone aware, through the temporary front page, that we had reason to believe that the database had been compromised.

We would like to reinforce the recommendation we made when the breach was first discovered. If you use the same password on other websites and you have not changed them already then please do so as a matter of urgency.

In an attempt to remain as open as possible and to keep everyone informed we would like to provide a short update.

The hacker had managed to upload a file to the server which allowed them full access to the website, its structure, and the option to freely perform queries to the DB.

Due to this level of access it is highly likely that the hacker will have been able to obtain user information from the DB which includes email addresses and hashed passwords. Combined with access to the salting mechanism the integrity of weak passwords cannot be guaranteed.

Because we are still unclear how this breach occurred the full functionality of the website cannot be restored. However, the problem set remains accessible at the normal web address.

Please be assured that we continue to do what we can to fix it.