 limitation that the
    iteration count must be an odd number.
   </p><p>
    To pick an appropriate iteration count, consider that
    the original DES crypt was designed to have the speed of 4 hashes per
    second on the hardware of that time.
    Slower than 4 hashes per second would probably dampen usability.
    Faster than 100 hashes per second is probably too fast.
   </p><p>
    <a class="xref" href="pgcrypto.html#PGCRYPTO-HASH-SPEED-TABLE" title="Table F.20. Hash Algorithm Speeds">Table F.20</