Most applications of hashes, to inputs that aren't passwords, are protected because their input space is so large that it can't be brute forced or because their input simply isn't secret. The speed of the hash function then becomes a feature instead of a weakness.
For example, suppose I give you the hash of a random 128 bit network packet payload, and you have hardware to evaluate the hash function I used a quintillion times per second. How long will it takes you to find that packet? Well, there's 2^256 possibilities and you go at a rate of 10^18 per second, so... 2^128/10^18s ~= 10 trillion years.
Key derivation functions (i.e. password hashes) are a specialized version of hash functions for private low-entropy inputs. They need to be slow to prevent quickly enumerating and evaluation all likely inputs. Paying that time cost would be unnecessary, wasteful, and bloated for inputs that are public or high-entropy.
For example, Git would suffer enormously if it used a key derivation function instead of a standard hash function. Useful operations like rebase and squash would go from taking milliseconds to taking minutes or hours.
For example, suppose I give you the hash of a random 128 bit network packet payload, and you have hardware to evaluate the hash function I used a quintillion times per second. How long will it takes you to find that packet? Well, there's 2^256 possibilities and you go at a rate of 10^18 per second, so... 2^128/10^18s ~= 10 trillion years.
Key derivation functions (i.e. password hashes) are a specialized version of hash functions for private low-entropy inputs. They need to be slow to prevent quickly enumerating and evaluation all likely inputs. Paying that time cost would be unnecessary, wasteful, and bloated for inputs that are public or high-entropy.
For example, Git would suffer enormously if it used a key derivation function instead of a standard hash function. Useful operations like rebase and squash would go from taking milliseconds to taking minutes or hours.