Student dedicates master's thesis to a system that identifies cheaters' additional accounts in Counter-Strike 2 by mouse and keyboard movements

Norwegian University of Science and Technology student Christopher B. Didriksen dedicated his Master's thesis to a biometric system that recognizes Counter-Strike 2 players by how they control their games. The method could help catch banned cheaters who register fresh accounts and jump back into matches.

Banning cheaters remains the main weapon against cheating in competitive shooters. But an account ban does little if an offender can create a new one in a few minutes. Didriksen decided to tie the punishment to the person rather than the profile.

He shared part of his findings on Reddit. Didriksen analyzed demos from competitive Counter-Strike 2 matches and built a "fingerprint" of each player from separate mouse and keyboard signals. According to him, it stays stable "across maps, sessions, settings [...] across matches played months apart, and across a sensitivity change from 800 to 640 eDPI."

Testing ran on a dataset of more than 1,000 players. Mouse movement biometrics correctly identified players "every time [...] but often only by a fine margin," while keyboard use "picked out the right player 98% of the time." Combining the two metrics identifies the human behind an account with high accuracy.

Didriksen noted that the method "found smurfs nobody had reported, and it is fast enough to check every new match against all of CS2's monthly players." A smurf is a secondary account belonging to an experienced or high-ranking player.

He suggests running the system alongside Valve Anti-Cheat and Trust Factor.

It would sit next to [Valve Anti-Cheat] and Trust Factor and answer the one question they can't. Is this the same human?

The thesis grew out of dissatisfaction with existing anti-cheat and banning systems. A banned player can make a new account and be "back in a match the same evening." Didriksen admits the solution is not perfect, since it essentially removes the possibility that a banned player may change their cheating ways on a fresh account. The system is also easily confounded by shared accounts used by several people.

Earlier this year, volunteers on Reddit signed up for the research, and some even revealed their smurf accounts. Didriksen called that data "some of the most valuable data I had." He added on r/CS2: "The thesis is now finished and got an A, and none of it would have been possible without you."