> added to the map can choose them so every key collides, resulting in a DoS the application creator needed to have anticipated this threat model, and they can

> added to the map can choose them so every key collides, resulting in a DoS the application creator needed to have anticipated this threat model, and they can prepare for it (for example, salt the keys). But to put onto every user a hash that is collision resistent, but costs performance, is unjustified because not every user needs it.