Embarrassingly, picking a hash function (say, for hashing strings, or sets of integers, etc.) is still magic to me: take some prime numbers here, magic constants there, do some bit shifting, modulo something, and done.
Is there a nice, gentle and approachable tutorial about creating hash functions?
It is curious how hard it is to find a basic explanation of hash algorithms. Maybe the topic is so difficult that it's not easy to make a basic tutorial. I was looking for one myself and ran into the same problem.
But you can try this page. What is cool about it is that after you read through the page, at the bottom there's a text box. If you add text to that box and submit the form, the result is a step-by-step listing of how it hashes the input text.
http://www.metamorphosite.com/one-way-hash-encryption-sha1-data-software
Good luck. If you find anything better, it would be really helpful if you posted it here.
