PHP encryption and decryption class

PHP encryption and decryption class

<?php

function i_array_column($input, $columnKey, $indexKey=null){
    if(!function_exists(&#39;array_column&#39;)){
        $columnKeyIsNumber  = (is_numeric($columnKey))?true:false;
        $indexKeyIsNull            = (is_null($indexKey))?true :false;
        $indexKeyIsNumber     = (is_numeric($indexKey))?true:false;
        $result                         = array();
        foreach((array)$input as $key=>$row){
            if($columnKeyIsNumber){
                $tmp= array_slice($row, $columnKey, 1);
                $tmp= (is_array($tmp) && !empty($tmp))?current($tmp):null;
            }else{
                $tmp= isset($row[$columnKey])?$row[$columnKey]:null;
            }
            if(!$indexKeyIsNull){
                if($indexKeyIsNumber){
                    $key = array_slice($row, $indexKey, 1);
                    $key = (is_array($key) && !empty($key))?current($key):null;
                    $key = is_null($key)?0:$key;
                }else{
                    $key = isset($row[$indexKey])?$row[$indexKey]:0;
                }
            }
            $result[$key] = $tmp;
        }
        return $result;
    }else{
        return array_column($input, $columnKey, $indexKey);
    }
}

function randcode($len, $mode = 2){
    $rcode = &#39;&#39;;
    switch($mode){
        case 1: //去除0、o、O、l等易混淆字符
            $chars = &#39;ABCDEFGHJKLMNPQRSTUVWXYZ23456789abcdefghijkmnpqrstuvwxyz&#39;;
            break;
        case 2: //纯数字
            $chars = &#39;0123456789&#39;;
            break;
        case 3: //全数字+大小写字母
            $chars = &#39;ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz&#39;;
            break;
        case 4: //全数字+大小写字母+一些特殊字符
            $chars = &#39;ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz~!@#$%^&*()&#39;;
            break;
    }

    $count = strlen($chars) - 1;
    mt_srand((double)microtime() * 1000000);
    for($i = 0; $i < $len; $i++) {
        $rcode .= $chars[mt_rand(0, $count)];
    }

    return $rcode;
}

/**
 * $string 明文或密文
 * $operation 加密ENCODE或解密DECODE
 * $key 密钥
 * $expiry 密钥有效期
 */
function authcode($string, $operation = &#39;DECODE&#39;, $key = &#39;&#39;, $expiry = 0) {
    $ckey_length = 4;
    $key = md5($key);
    $keya = md5(substr($key, 0, 16));
    $keyb = md5(substr($key, 16, 16));
    $keyc = $ckey_length ? ($operation == &#39;DECODE&#39; ? substr($string, 0, $ckey_length): 
    substr(md5(microtime()), -$ckey_length)) : &#39;&#39;;

    $cryptkey = $keya.md5($keya.$keyc);
    $key_length = strlen($cryptkey);

    $string = $operation == &#39;DECODE&#39; ? base64_decode(substr($string, $ckey_length)) : 
    sprintf(&#39;%010d&#39;, $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;
    $string_length = strlen($string);

    $result = &#39;&#39;;
    $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($operation == &#39;DECODE&#39;) {
        if((substr($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 &#39;&#39;;
        }
    } else {
        return $keyc.str_replace(&#39;=&#39;, &#39;&#39;, base64_encode($result));
    }
}

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