title: compressing a SHA-256 hash
body: <p>I want to automatically generate Java's serialVersionUID (which is a long, or 64 bits).  What distinguishes the object to be serialized is determined by about 20 integers, but not always 20 integers.  I intend to convert the integers into a comma separated string of numbers and run it through the SHA-256 hash function.</p>
  
  <p>Since SHA-256 is 32 bytes long (256 bits), and I need it to fit into the serialVersionUID (64 bits), how might I convert it to a 64 bit value and minimize the loss of the characteristics of a good hash?</p>