title: Is there more chance having collisions between GUID's or a SHA1 hashes of GUID's?
body: <p>Is there more chance having collisions when betweens <code>GUID's</code> (128 bits) or SHA1 hashes of <code>GUID's</code> (160 bits) ? My opinion is there is less chance with a <code>GUID</code> (even if there is 32 bit less), because it has some special mechanisms to make sure it is (almost, because no guarantee) unique (ex : timestamp) </p>
  
  <p>Note : i already know that a <code>GUID</code> is very unlikely to have a collision with another <code>GUID</code>, no more debate about this please.</p>