Summary of commonly used encryption and decryption methods in PHP

php encryption and decryption: PHP encryption and decryption functions can usually be used to encrypt some useful strings and store them in the database or as tokens for synchronous login between various subsystems, and decrypt the strings through the decryption algorithm. This function uses base64 and MD5 encryption and decryption.

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①The first encryption and decryption algorithm

<?php  
function encryptDecrypt($key, $string, $decrypt){   
    if($decrypt){   
        $decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($string), MCRYPT_MODE_CBC, md5(md5($key))), "12");   
        return $decrypted;   
    }else{   
        $encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $string, MCRYPT_MODE_CBC, md5(md5($key))));   
        return $encrypted;   
    }   
}   
  
//加密:"z0JAx4qMwcF+db5TNbp/xwdUM84snRsXvvpXuaCa4Bk="  
echo encryptDecrypt(&#39;password&#39;, &#39;Helloweba欢迎您&#39;,0);   
//解密:"Helloweba欢迎您"  
echo encryptDecrypt(&#39;password&#39;, &#39;z0JAx4qMwcF+db5TNbp/xwdUM84snRsXvvpXuaCa4Bk=&#39;,1);  
?>

②The second encryption and decryption algorithm:

<?php  
//加密函数  
function lock_url($txt,$key=&#39;www.zhuoyuexiazai.com&#39;){  
    $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-=+";  
    $nh = rand(0,64);  
    $ch = $chars[$nh];  
    $mdKey = md5($key.$ch);  
    $mdKey = substr($mdKey,$nh%8, $nh%8+7);  
    $txt = base64_encode($txt);  
    $tmp = &#39;&#39;;  
    $i=0;$j=0;$k = 0;  
    for ($i=0; $i<strlen($txt); $i++) {  
        $k = $k == strlen($mdKey) ? 0 : $k;  
        $j = ($nh+strpos($chars,$txt[$i])+ord($mdKey[$k++]))%64;  
        $tmp .= $chars[$j];  
    }  
    return urlencode($ch.$tmp);  
}  
//解密函数  
function unlock_url($txt,$key=&#39;www.zhuoyuexiazai.com&#39;){  
    $txt = urldecode($txt);  
    $chars = "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 = &#39;&#39;;  
    $i=0;$j=0; $k = 0;  
    for ($i=0; $i<strlen($txt); $i++) {  
        $k = $k == strlen($mdKey) ? 0 : $k;  
        $j = strpos($chars,$txt[$i])-$nh - ord($mdKey[$k++]);  
        while ($j<0) $j+=64;  
        $tmp .= $chars[$j];  
    }  
    return base64_decode($tmp);  
}  
?>

③The third encryption and decryption algorithm:

<?php  
  
//改进后的算法  
//加密函数  
function lock_url($txt,$key=&#39;zhuoyuexiazai&#39;){  
    $txt = $txt.$key;  
    $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-=+";  
    $nh = rand(0,64);  
    $ch = $chars[$nh];  
    $mdKey = md5($key.$ch);  
    $mdKey = substr($mdKey,$nh%8, $nh%8+7);  
    $txt = base64_encode($txt);  
    $tmp = &#39;&#39;;  
    $i=0;$j=0;$k = 0;  
    for ($i=0; $i<strlen($txt); $i++) {  
        $k = $k == strlen($mdKey) ? 0 : $k;  
        $j = ($nh+strpos($chars,$txt[$i])+ord($mdKey[$k++]))%64;  
        $tmp .= $chars[$j];  
    }  
    return urlencode(base64_encode($ch.$tmp));  
}  
//解密函数  
function unlock_url($txt,$key=&#39;zhuoyuexiazai&#39;){  
    $txt = base64_decode(urldecode($txt));  
    $chars = "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 = &#39;&#39;;  
    $i=0;$j=0; $k = 0;  
    for ($i=0; $i<strlen($txt); $i++) {  
        $k = $k == strlen($mdKey) ? 0 : $k;  
        $j = strpos($chars,$txt[$i])-$nh - ord($mdKey[$k++]);  
        while ($j<0) $j+=64;  
        $tmp .= $chars[$j];  
    }  
    return trim(base64_decode($tmp),$key);  
}  
  
?>

④The fourth encryption and decryption algorithm:

<?php  
  
function passport_encrypt($txt, $key = &#39;www.zhuoyuexiazai.com&#39;) {   
    srand((double)microtime() * 1000000);   
    $encrypt_key = md5(rand(0, 32000));   
    $ctr = 0;   
    $tmp = &#39;&#39;;   
    for($i = 0;$i < strlen($txt); $i++) {   
    $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;   
    $tmp .= $encrypt_key[$ctr].($txt[$i] ^ $encrypt_key[$ctr++]);   
    }   
    return urlencode(base64_encode(passport_key($tmp, $key)));   
}   
  
function passport_decrypt($txt, $key = &#39;www.zhuoyuexiazai.com&#39;) {   
    $txt = passport_key(base64_decode(urldecode($txt)), $key);   
    $tmp = &#39;&#39;;   
    for($i = 0;$i < strlen($txt); $i++) {   
    $md5 = $txt[$i];   
    $tmp .= $txt[++$i] ^ $md5;   
    }   
    return $tmp;   
}   
  
function passport_key($txt, $encrypt_key) {   
    $encrypt_key = md5($encrypt_key);   
    $ctr = 0;   
    $tmp = &#39;&#39;;   
    for($i = 0; $i < strlen($txt); $i++) {   
    $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;   
    $tmp .= $txt[$i] ^ $encrypt_key[$ctr++];   
    }   
    return $tmp;   
}   
   
  
$txt = "1";   
$key = "testkey";   
$encrypt = passport_encrypt($txt,$key);   
$decrypt = passport_decrypt($encrypt,$key);   
  
echo $encrypt."<br>";   
echo $decrypt."<br>";   
  
?>

⑤The fifth encryption and decryption algorithm: encryption used in discuz Decryption algorithm

Sometimes in the project we need to use PHP to encrypt specific information, that is, to generate an encrypted string through the encryption algorithm. This encrypted string can be decrypted through the decryption algorithm, which facilitates the decryption by the program. The subsequent information is processed. The most common applications are in user login and some API data exchange scenarios. The most common applications are in user login and some API data exchange scenarios. The principle of encryption and decryption is generally to use a certain encryption and decryption algorithm, add the key to the algorithm, and finally obtain the encryption and decryption results.

<?php  
//非常给力的authcode加密函数,Discuz!经典代码(带详解)  
//函数authcode($string, $operation, $key, $expiry)中的$string：字符串，明文或密文；$operation：DECODE表示解密，其它表示加密；$key：密匙；$expiry：密文有效期。  
function authcode($string, $operation = &#39;DECODE&#39;, $key = &#39;&#39;, $expiry = 0) {     
    // 动态密匙长度，相同的明文会生成不同密文就是依靠动态密匙     
    $ckey_length = 4;     
         
    // 密匙     
    $key = md5($key ? $key : $GLOBALS[&#39;discuz_auth_key&#39;]);     
         
    // 密匙a会参与加解密     
    $keya = md5(substr($key, 0, 16));     
    // 密匙b会用来做数据完整性验证     
    $keyb = md5(substr($key, 16, 16));     
    // 密匙c用于变化生成的密文     
    $keyc = $ckey_length ? ($operation == &#39;DECODE&#39; ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$ckey_length)) : &#39;&#39;;     
    // 参与运算的密匙     
    $cryptkey = $keya.md5($keya.$keyc);     
    $key_length = strlen($cryptkey);     
    // 明文，前10位用来保存时间戳，解密时验证数据有效性，10到26位用来保存$keyb(密匙b)，   
    //解密时会通过这个密匙验证数据完整性     
    // 如果是解码的话，会从第$ckey_length位开始，因为密文前$ckey_length位保存 动态密匙，以保证解密正确     
    $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);     
    $rndkey = array();     
    // 产生密匙簿     
    for($i = 0; $i <= 255; $i++) {     
        $rndkey[$i] = ord($cryptkey[$i % $key_length]);     
    }     
    // 用固定的算法，打乱密匙簿，增加随机性，好像很复杂，实际上对并不会增加密文的强度     
    for($j = $i = 0; $i < 256; $i++) {     
        $j = ($j + $box[$i] + $rndkey[$i]) % 256;     
        $tmp = $box[$i];     
        $box[$i] = $box[$j];     
        $box[$j] = $tmp;     
    }     
    // 核心加解密部分     
    for($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;     
        // 从密匙簿得出密匙进行异或，再转成字符     
        $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));     
    }     
    if($operation == &#39;DECODE&#39;) {    
        // 验证数据有效性，请看未加密明文的格式     
        if((substr($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 {     
        // 把动态密匙保存在密文里，这也是为什么同样的明文，生产不同密文后能解密的原因     
        // 因为加密后的密文可能是一些特殊字符，复制过程可能会丢失，所以用base64编码     
        return $keyc.str_replace(&#39;=&#39;, &#39;&#39;, base64_encode($result));     
    }     
}   
  
$str = &#39;abcdef&#39;;   
$key = &#39;www.helloweba.com&#39;;   
echo authcode($str,&#39;ENCODE&#39;,$key,0); //加密   
$str = &#39;56f4yER1DI2WTzWMqsfPpS9hwyoJnFP2MpC8SOhRrxO7BOk&#39;;   
echo authcode($str,&#39;DECODE&#39;,$key,0); //解密   
  
?>

⑥The sixth encryption and decryption algorithm:

<?php  
//函数encrypt($string,$operation,$key)中$string：需要加密解密的字符串；$operation：判断是加密还是解密，E表示加密，D表示解密；$key：密匙。  
function encrypt($string,$operation,$key=&#39;&#39;){   
    $key=md5($key);   
    $key_length=strlen($key);   
      $string=$operation==&#39;D&#39;?base64_decode($string):substr(md5($string.$key),0,8).$string;   
    $string_length=strlen($string);   
    $rndkey=$box=array();   
    $result=&#39;&#39;;   
    for($i=0;$i<=255;$i++){   
           $rndkey[$i]=ord($key[$i%$key_length]);   
        $box[$i]=$i;   
    }   
    for($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($operation==&#39;D&#39;){   
        if(substr($result,0,8)==substr(md5(substr($result,8).$key),0,8)){   
            return substr($result,8);   
        }else{   
            return&#39;&#39;;   
        }   
    }else{   
        return str_replace(&#39;=&#39;,&#39;&#39;,base64_encode($result));   
    }   
}   
  
$str = &#39;abc&#39;;   
$key = &#39;www.helloweba.com&#39;;   
$token = encrypt($str, &#39;E&#39;, $key);   
echo &#39;加密:&#39;.encrypt($str, &#39;E&#39;, $key);   
echo &#39;解密：&#39;.encrypt($str, &#39;D&#39;, $key);  
  
?>

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