$str = ‘test‘;
$cm = md5($str);
$bm = md5($str, true);
$cstr = implode(unpack(‘H*‘, $bm));
$bstr = pack(‘H*‘, $cm);
echo ‘str:‘. $str . "<br >\n";
echo ‘cm :‘ . $cm . "<br >\n";
echo ‘cstr:‘ . $cstr . "<br >\n";
echo ‘urlencode(bm) :‘ . urlencode($bm) . "<br >\n";
echo ‘urlencode(bstr):‘ . urlencode($bstr) . "<br >\n";
原文：http://www.jb51.net/article/45008.htm