easy hash algorithm to use without computer
There has been a similar question. The accepted answer there refers to Manuel Blum's HCMU hash function.

Check out Manuel Blum's human computable hash function. He calls it HCMU for Human Computable Machine Unbreakable.
He claims you have to spend an hour memorizing the technique and then you can apply the has function in about 20 seconds without even using pencil and paper.

I have found an implemention of this function here, in just over 60 lines of Python code. Unfortunately I cannot find any paper on it on the go and the link in that other question is broken.