求兼容PHP5.5和5.6的des加解密函数或类

<?phpclass DES{ var $key; var $iv; //偏移量  function DES( $key, $iv=0 ) { //key长度8例如:1234abcd  $this->key = $key;  if( $iv == 0 ) {   $this->iv = $key;  } else {   $this->iv = $iv; //mcrypt_create_iv ( mcrypt_get_block_size (MCRYPT_DES, MCRYPT_MODE_CBC), MCRYPT_DEV_RANDOM );  } }  function encrypt($str) { //加密，返回大写十六进制字符串  $size = mcrypt_get_block_size ( MCRYPT_DES, MCRYPT_MODE_CBC );  $str = $this->pkcs5Pad ( $str, $size );  return strtoupper( bin2hex( mcrypt_cbc(MCRYPT_DES, $this->key, $str, MCRYPT_ENCRYPT, $this->iv ) ) ); }  function decrypt($str) { //解密  $strBin = $this->hex2bin( strtolower( $str ) );  $str = mcrypt_cbc( MCRYPT_DES, $this->key, $strBin, MCRYPT_DECRYPT, $this->iv );  $str = $this->pkcs5Unpad( $str );  return $str; }  function hex2bin($hexData) {  $binData = "";  for($i = 0; $i < strlen ( $hexData ); $i += 2) {   $binData .= chr ( hexdec ( substr ( $hexData, $i, 2 ) ) );  }  return $binData; }  function pkcs5Pad($text, $blocksize) {  $pad = $blocksize - (strlen ( $text ) % $blocksize);  return $text . str_repeat ( chr ( $pad ), $pad ); }  function pkcs5Unpad($text) {  $pad = ord ( $text {strlen ( $text ) - 1} );  if ($pad > strlen ( $text ))   return false;  if (strspn ( $text, chr ( $pad ), strlen ( $text ) - $pad ) != $pad)   return false;  return substr ( $text, 0, - 1 * $pad ); }}$my_encrypt = new DES('qwertyuiop');echo $my_encrypt->encrypt('1234567');

function encrypt($str, $key)  {      $block = mcrypt_get_block_size('des', 'ecb');      $pad = $block - (strlen($str) % $block);      $str .= str_repeat(chr($pad), $pad);      return mcrypt_encrypt(MCRYPT_DES, $key, $str, MCRYPT_MODE_ECB);}function decrypt($str, $key)  {        $str = mcrypt_decrypt(MCRYPT_DES, $key, $str, MCRYPT_MODE_ECB);      $block = mcrypt_get_block_size('des', 'ecb');      $pad = ord($str[($len = strlen($str)) - 1]);      return substr($str, 0, strlen($str) - $pad);  }