highwayhash

> why is "iteration" even possible over a hash table? Going through all items in a container seems like a logical thing to want to do. > Shouldn't the keys be specified as a "set" on which only set-appropriate operations like map can be performed? Efficient implementation (in space and time) of these set operations would limit the possible efficient implementations of a hash table (i.e. to using the hash value as a key in an ordered map). Going one step further, this guarantee would freeze behaviour of the hash function (and how they are combined) for all time; optimisations for different architectures would not be possible, nor would avoiding hash collision attacks by changing seeds. Sometimes hash value stability is what you want (e.g. when transmitting data in space and time), so "frozen" hash functions give these guarantees e.g. https