Hash functions are used by many attackers and web application which will decadent hash tables. Moreover, that multiple keys give the same hash value in case of a collision hashes will not be used. so, it can look up a value in the array. String compares for each entry will be done. As we know that this wants more CPU power than using hashes to calculate the index key value. also, whenever a hacker sends a HTTP request in which he purposely uses two keys which give the same hash and adds several thousands of other variables, the CPU of the webserver will be quite busy when looking up variables. POST requests are more interesting for this attack, because a request body can contain more data than the URL.
Perform and Internet search on the Big O of hash functions and discuss your findings. We have said that the Big O is (1) if there are no collisions, and to account for searching due to collisions, we take an average value for the amount of searches necessary to find a spot to place the item. Given that the number of searches increases (dramatically) as the table fills up, what can we say about the Big O (1), is is really constant? if not, what is it?