//加密函数
function lockcode($code) {
 static $source_string = 'E5FCDG3HQA4B1NOPIJ2RSTUV67MWX89KLYZ';
 $num = $code;
 $code = '';
 while ( $num > 0) {
  $mod = $num % 35;
  $num = ($num - $mod) / 35;
  $code = $source_string[$mod].$code;
 }
 if(empty($code[3]))
  $code = str_pad($code,4,'0',STR_PAD_LEFT);
 return $code;
}
//解密函数
function unlockcode($code) {
 static $source_string = 'E5FCDG3HQA4B1NOPIJ2RSTUV67MWX89KLYZ';
 if (strrpos($code, '0') !== false)
  $code = substr($code, strrpos($code, '0')+1);
 $len = strlen($code);
 $code = strrev($code);
 $num = 0;
 for ($i=0; $i < $len; $i++) {
  $num += strpos($source_string, $code[$i]) * pow(35, $i);
 }
 return $num;
}

//加密函数 
function encrypt($data,$key='CHENI'){ 
 $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 
 $nh = rand(0,64); 
 $ch = $chars[$nh]; 
 $mdKey = md5($key.$ch); 
 $mdKey = substr($mdKey,$nh%8, $nh%8+7); 
 $data= base64_encode($data); 
 $tmp = ''; 
 $i=0;$j=0;$k = 0; 
 for ($i=0; $i<strlen($data); $i++) { 
  $k = $k == strlen($mdKey) "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; 
 $ch = $txt[0]; 
 $nh = strpos($chars,$ch); 
 $mdKey = md5($key.$ch); 
 $mdKey = substr($mdKey,$nh%8, $nh%8+7); 
 $txt = substr($txt,1); 
 $tmp = ''; 
 $i=0;$j=0; $k = 0; 
 for ($i=0; $i<strlen($txt); $i++) { 
  $k = $k == strlen($mdKey) "htmlcode">

function encrypt($data, $key) { 
 $char="";
 $str="";
 $key = md5($key); 
 $x  = 0; 
 $len = strlen($data); 
 $l  = strlen($key); 
 for ($i = 0; $i < $len; $i++) { 
  if ($x == $l) { $x = 0; } 
  $char .= $key{$x}; 
  $x++; 
 } 
 for ($i = 0; $i < $len; $i++){ 
  $str .= chr(ord($data{$i}) + (ord($char{$i})) % 256); 
 } 
 return base64_encode($str); 
} 
function decrypt($data, $key) { 
 $key = md5($key); 
 $x = 0; 
 $data = base64_decode($data); 
 $len = strlen($data); 
 $l = strlen($key); 
 for ($i = 0; $i < $len; $i++) { 
  if ($x == $l){ $x = 0;} 
  $char .= substr($key, $x, 1); 
  $x++; 
 } 
 for ($i = 0; $i < $len; $i++){ 
  if (ord(substr($data, $i, 1)) < ord(substr($char, $i, 1))){ 
   $str .= chr((ord(substr($data, $i, 1)) + 256) - ord(substr($char, $i, 1))); 
  }else{ 
   $str .= chr(ord(substr($data, $i, 1)) - ord(substr($char, $i, 1))); 
  } 
 } 
 return $str; 
}



四、这个是我用过最好用的一个了，discuz中使用的加密解密算法


//加密算法
 function authcode($string,$key='',$operation=false,$expiry=0){
  $ckey_length = 4;
  $key = md5($key ? $key : DEFAULT_KEYS);
  $keya = md5(substr($key, 0, 16));
  $keyb = md5(substr($key, 16, 16));
  $keyc = $ckey_length ? ($operation? substr($string, 0, $ckey_length):substr(md5(microtime()), -$ckey_length)) : '';
  $cryptkey = $keya.md5($keya.$keyc);
  $key_length = strlen($cryptkey);
  $string = $operation? base64_decode(substr($string, $ckey_length)) :
  sprintf('%010d', $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;
  $string_length = strlen($string);
  $result = '';
  $box = range(0, 255);
  $rndkey = array();
  for($i = 0; $i <= 255; $i++) {
   $rndkey[$i] = ord($cryptkey[$i % $key_length]);
  }
  for($j = $i = 0; $i < 256; $i++) {
   $j = ($j + $box[$i] + $rndkey[$i]) % 256;
   $tmp = $box[$i];
   $box[$i] = $box[$j];
   $box[$j] = $tmp;
  }
  for($a = $j = $i = 0; $i < $string_length; $i++) {
   $a = ($a + 1) % 256;
   $j = ($j + $box[$a]) % 256;
   $tmp = $box[$a];
   $box[$a] = $box[$j];
   $box[$j] = $tmp;
   $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
  }
  if($operation) {
   if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) &&
    substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {
    return substr($result, 26);
   } else {
    return '';
   }
  } else {
   return $keyc.str_replace('=', '', base64_encode($result));
  }
 }
 echo authcode('123456','key');
 echo '<br>';
 echo authcode('7d49kn9k07uSBZvha8as+/qm4UoLfpy88PFg12glPeDtlzc','key',true);


以上几种都是比较好用且是我自己常用的分享给大家，大家如果想要了解其他的加密函数或者有什么建议可以在底部留言。