Question

I need a secure (cryptographic) hash function with the following properties:

1. Can be coded in as few lines as possible (in R5RS Scheme). Hopefully under 50.
2. Memory and CPU performance within reason for password-length data. (e.g. it does not have to be super efficient or create hashes for millions of bytes of data)

Most secure hash functions I can find are designed with speed/memory efficiency in mind and are complex to code as a result.

The current candidate is Mash-1 (or Mash-2):
Handbook of applied cryptography. Google Books

Thanks.

Edit:
Thank you all for your answers so far. Please forgive me if the following comes off as rude, I just want to be clear. Please trust me that I have done my homework and considered the “standard” options. I know the easiest thing to do is use one of those, but that’s not what I’m looking for.

The single question I am trying to answer is:
What cryptographically secure hash algorithm can be implemented in the smallest amount of “readable” code?

I have already posted the best candidate I could find. Any suggestions about something simpler, or commentary about Mash-1/2 would be most helpful.

Answer 1

If you prefer simplicity and pedagogical value over efficiency then the VSH hash function might be an option. It comes with strong arguments that VSH is a collision resistant hash function, though this function lacks some other properties (e.g. pseudorandomness) that other hash functions have.