I'm wondering why it's so hard to find collisions for cryptographic hashes.
Take for example a hash function that outputs a
64 bit hash.
In order to find collisions, if you feed the function every single
65 bit string possible, aren't you guaranteed to find a collision? The hash function has to turn
65 bits into
64 bits so is has to find some collisions.
Can't a collision be found in a pretty straightforward way using this technique?
I understand computing all of them will take a lot of time but it seems pretty reasonable to do so and create a database index to store them in so hashes can be broken.