Creating a hash of XOR'd blocks Suppose a message $m$ is divided into blocks of length $160$ bits: $m
&gt; = M_1 || M_2 || ... || M_l$ And define $h(m) = M_1 \oplus M_2 \oplus ... \oplus M_l$
  
  Which of the three desirable properties of a good cryptographic hash
  function does h satisfy? Show that it does not satisfy the other two.


Three desirable properties of a cryptographic hash function
http://en.wikipedia.org/wiki/Cryptographic_hash_function#Properties

I feel like if there is only one, like the question states, it has to be the first one, preimage resistance.  However, given a hash $h = 000....0$
I can find a bunch of $m$'s that could give that particular hash.  Maybe since there are lots of solutions you can't pin point the specific $m$ that gave that value?

What do you think?
I believe that this is a poorly written question: such an $h$ obviously doesn't have either preimage resistance, second preimage resistance or collision resistance.

The inability to rederive the specific value of $m$ based on its hash is not an interesting property; it's pretty much true of any function which generates an output shorter than its input.

I don't know where you're getting these questions from; based on this question, I'd suggest you look elsewhere.