From Friday, December 24th to Monday, December 27th, we'll be hosting An Animal Contest 4. Participants will have a 3-hour window to complete 6 problems centered around christmas! See the contest page for more details.
Note that AAC4 is not rated for users with at least 2400 rating.
On Friday, December 17th, 2021, we'll be running the second SAC Code Challenge for this year!
You can write this year's contest in any two-hour window between December 17th, 00:00 EST, until December 21st, 00:00 EST. The contest will be composed of 5 problems with problem difficulty ranging from CCC Junior 1 to CCC Senior 3.
Additionally, the problems will be themed around Christmas.
Like the most recent Code Challenge, there will be no registration requirements to participate.
On Friday, October 29th, 2021, we'll be running the first annual and second-ever SAC Code Challenge!
You can write this year's contest in any two-hour window between October 29th, 00:00 EDT, until November 1st, 00:00 EDT. The contest will be composed of 5 problems with problem difficulty ranging from CCC Junior 1 to CCC Senior 3.
Additionally, the problems will be themed around Halloween.
Unlike last year, there will be no registration requirements to participate.
In light of recent events, DMOJ administrators have decided to not process any support requests about account recovery, starting January 1st, 2022 (which is now in effect). If you lose your second authentication factor, you must use the recovery code generated when you enabled two-factor authentication (2FA). If you do not have a recovery code, access to your account will be lost forever. This is done purely for security reasons, to protect you from social engineering attacks.
Two-factor authentication is designed to protect an account even when the password (or equivalently, the email with which the user could reset it) is compromised. Therefore, a genuine recovery request is indistinguishable from the following attack:
Suppose you are Alice, and an attacker Mallory has somehow gained access to your email. Then, Mallory can send an email to the DMOJ admins, claiming that she is Alice, has lost her phone, and begs the admins to reset 2FA. Since the admins do not know either Alice or Mallory in real life, it is conceivable that an admin could be tricked into believing Mallory is really Alice and granting the request. Now, Mallory obtains access to the account Alice, even though 2FA is supposed to prevent her from doing so.
Therefore, the only option DMOJ admins have to safeguard your account security is to ignore all support requests about account recovery. Please keep your recovery codes safe. If you don't know them, you can go to the edit profile page, regenerate them, and store them in a safe place. Thank you.