# Tag Info

Accepted

### What exactly (and precisely) is "hash?"

The Wikipedia article on hash functions is very good, but I will here give my take. What is a hash? "Hash" is really a broad term with different formal meanings in different contexts. There ...

### Do passwords need a max length?

No. There is no* limit on the length of the input to for most* good cryptographic hash functions. As a result, password hashing can support passwords of unlimited length and do not need to impose a ...

### What exactly (and precisely) is "hash?"

A hash function is a function that takes an input and produces a value of fixed size. For example you might have a hash function stringHash that accepts a ...

### Do passwords need a max length?

Yes, passwords need maximum length, but not because of collision risk (see other answers regarding collisions). Reason for setting maximum length - possibility of denial of service attack. Someone ...

### Do passwords need a max length?

As hashes are fixed length, does that mean that even if not specified when creating the password, all login systems would need to have some sort of maximum input length (although probably very high)? ...
Accepted

### Two-way Hash Functions

Yes, this is possible. Here are two examples of such a function. One function is $f(x)=x$. This has no collisions, and the function is easy to invert. Here is another function: define $f(x) = x$ ...
Accepted

### Hash functions and pathological data sets

An easy way to visualize this is to imagine a hash table of size $n$ (implemented with chaining) that contains all of the elements of $U$ (even though this is unrealistic in practice because $U$ ...
Accepted

### Understanding hashtable performance in the worst-case

The load factor denotes the average expected length of a chain, therefore it is interesting for an average case analysis, not the worst case analysis. That's why on average you expect needing constant ...

### Hash function to hash 6-digit positive integers

I think you've missed the point of hash tables. Hash tables are used to give array-like access to a dataset that's too big and sparse to store in an array. So, for example, it sounds like you're ...