那位大神能把我这个Java的md5的加密方法写个php版本哦，感激噢!

Question

那位大神能把我这个Java的md5的加密方法写个php版本哦，感激噢，Java代码如下！
写这个的人 描述的思路如下
1.将秘钥、源串分别转换byte数组
2.声明2个64位数组 将key的byte数组分别做异或运算填充进去 并分别补充 54、92 补满64长度
3.获得md5摘要算法的MessageDigest 对象
4.使用其中一个数组及源串的数组更新MessageDigest 摘要 完成哈希计算
5.重置摘要
6.使用另一个数组更新摘要 使用4中结果 从0到16开始更新摘要 完成哈希计算
7.转换字符串
public String cryptMd5(String source, String key) {
byte[] k_ipad = new byte[64];
byte[] k_opad = new byte[64];
byte[] keyb;
byte[] value;
try { byte[] keyb = key.getBytes("UTF-8");
value = source.getBytes("UTF-8");
}
catch (UnsupportedEncodingException e)
{
byte[] value;
keyb = key.getBytes();
value = source.getBytes();
}
Arrays.fill(k_ipad, keyb.length, 64, 54);
Arrays.fill(k_opad, keyb.length, 64, 92);
for (int i = 0; i < keyb.length; i++)
{
k_ipad[i] = (byte)(keyb[i] ^ 0x36);
k_opad[i] = (byte)(keyb[i] ^ 0x5C);
}
MessageDigest md = null;
try
{
md = MessageDigest.getInstance("MD5");
}
catch (NoSuchAlgorithmException e)
{
return null;
}
md.update(k_ipad);
md.update(value);
byte[] dg = md.digest();
md.reset();
md.update(k_opad);
md.update(dg, 0, 16);
dg = md.digest();
return toHex(dg); }

public static String toHex(byte[] input)
{
if (input == null) {
return null;
}
StringBuffer output = new StringBuffer(input.length * 2);
for (int i = 0; i < input.length; i++)
{
int current = input[i] & 0xFF;
if (current < 16)
output.append("0");
output.append(Integer.toString(current, 16));
}

return output.toString();

}

Answer 1

 function cryptMd5($source, $key) {
  if(! mb_check_encoding($source, 'utf-8')) $source = mb_convert_encoding($source, "utf-8", "auto");
  if(! mb_check_encoding($key, 'utf-8')) $key = mb_convert_encoding($key, "utf-8", "auto");
  $k_ipad = str_pad($key, 64, chr(54));  
  $k_opad = str_pad($key, 64, chr(92));
  for($i=0; $i<strlen($key); $i++) {
    $k_ipad{$i} = $key{$i} ^ chr(0x36);
    $k_opad{$i} = $key{$i} ^ chr(0x5c);
  }
  $dg = md5($source . substr($k_ipad, strlen($source)), true);
  $dg = md5(substr($dg, 0, 16) . substr($k_opad, 16), true);
  return bin2hex($dg);
}