The worst case for a hashtable degenerating to a linked list can be often exploited to form a DOS attack. It is enough that user controls the keys inserted to t

The worst case for a hashtable degenerating to a linked list can be often exploited to form a DOS attack. It is enough that user controls the keys inserted to the hashtable and the hash function is not cryptographically secure (typically they are not for performance reasons). That's why it is much wiser to use a binary tree for resolving collisions. So in this case - the worst case analysis is useful.