Out of academic curiosity: what is the principle by which VK determines the tracks that are supposed to be blocked?

Question

Social media

There is a public dedicated to the musical group.
Most of the tracks in this group are unplayable.
Why and how?

Answer 1

How does shazam work? The principle is the same.

Answer 2

The copyright holder came and said "this track can't be listened to".
VK took the track, removed the hash from it and blocks all new uploads,
counting and checking the hash with the table of blocked ones,
and the uploaded track will be changed as inaccessible.
maybe so =)