Two classic PHP encryption and decryption functions-PHP source code

This article mainly introduces two classic PHP encryption and decryption functions, one is Discuz! The authcode encryption function (with detailed decomposition), one is the encrypt () function, are more classic, you can refer to the next article to introduce two classic PHP encryption and decryption functions. one is Discuz! The authcode encryption function (with detailed decomposition). one is the encrypt () function, which is classic. For more information, see

In projects, we sometimes need to use PHP to encrypt specific information, that is, to generate an encrypted string through the encryption algorithm. the encrypted string can be decrypted through the decryption algorithm, this allows the program to process the decrypted information.
The most common applications are user logon and some API data exchange scenarios.

I have collected some classic PHP encryption and decryption function code and shared it with you. Encryption and decryption principles are generally based on a certain number of encryption and decryption algorithms, add the key to the algorithm, and finally obtain the encryption and decryption results.
1. very powerful authcode encryption function, Discuz! Classic code (detailed description ):

The code is as follows:

Function authcode ($ string, $ operation = 'Decode', $ key = '', $ expiry = 0) {// The length of the dynamic key, the same plaintext will generate different ciphertext based on the dynamic key $ ckey_length = 4; // key $ key = md5 ($ key? $ Key: $ GLOBALS ['discuz _ auth_key ']); // key a Participates in encryption and decryption $ keya = md5 (substr ($ key, 0, 16 )); // key B is used for data integrity verification $ keyb = md5 (substr ($ key, 16, 16 )); // key c is used to change the generated ciphertext $ keyc = $ ckey_length? ($ Operation = 'decode '? Substr ($ string, 0, $ ckey_length): substr (md5 (microtime (),-$ ckey_length )):''; // calculate the key $ cryptkey = $ keya. md5 ($ keya. $ keyc); $ key_length = strlen ($ cryptkey); // plaintext. the first 10 digits are used to save the timestamp. data validity is verified during decryption, 10 to 26 bits are used to save $ keyb (key B). // This key is used for data integrity verification during decryption. // if the key is decoded, it starts from the $ ckey_length bit, because the $ ckey_length bit before the ciphertext stores the dynamic key to ensure correct decryption $ string = $ operation = 'decode '? 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 (); // Generate a key book for ($ I = 0; $ I <= 255; $ I ++) {$ rndkey [$ I] = ord ($ cryptkey [$ I % $ key_length]);} // use a fixed algorithm to disrupt the key book and increase randomness. it seems complicated, in fact, the ciphertext strength is not added. for ($ j = $ I = 0; $ I <256; $ I ++) {$ j = ($ j + $ box [$ I] + $ rndkey [$ I]) % 256; $ tmp = $ box [$ I]; $ box [$ I] = $ box [$ j]; $ box [$ j] = $ tmp ;} // core encryption and decryption part 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; // The Keys obtained from the key book are different or, then convert it into a character $ result. = chr (ord ($ string [$ I]) ^ ($ box [($ box [$ a] + $ box [$ j]) % 256]);} if ($ operation = 'decode') {// verify the data validity. see the unencrypted plaintext format 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 {// Save the dynamic key in the ciphertext, this is also the reason why different ciphertext texts can be decrypted in the same plain text. // because the encrypted ciphertext may be special characters, the replication process may be lost, therefore, return $ keyc is encoded in base64 format. str_replace ('=', '', base64_encode ($ result ));}}

$ String: string, plaintext or ciphertext in the authcode ($ string, $ operation, $ key, $ expiry) function; $ operation: DECODE indicates decryption; others indicate encryption; $ key: key; $ expiry: ciphertext validity period.

Usage:

The code is as follows:

$ Str = 'abcdef '; $ key = 'www .helloweba.com'; echo authcode ($ str, 'encoding', $ key, 0 ); // encrypt $ str = '56f4yer1di2wtzwmqsfpps9hwyojnfp2mpc8sohrrxo7bok '; echo authcode ($ str, 'Decode', $ key, 0); // decrypt

2. encryption and decryption function encrypt ():

The code is as follows:

function encrypt($string,$operation,$key=''){     $key=md5($key);     $key_length=strlen($key);       $string=$operation=='D'?base64_decode($string):substr(md5($string.$key),0,8).$string;     $string_length=strlen($string);     $rndkey=$box=array();     $result='';     for($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($operation=='D'){         if(substr($result,0,8)==substr(md5(substr($result,8).$key),0,8)){             return substr($result,8);         }else{             return'';         }     }else{         return str_replace('=','',base64_encode($result));     } }

$ String in the encrypt ($ string, $ operation, $ key) function: the string to be encrypted and decrypted; $ operation: determines whether the string is encrypted or decrypted. E indicates encryption, and D indicates decryption; $ key: the key.
Usage:

The code is as follows:

$ Str = 'abc'; $ key = 'www .helloweba.com '; $ token = encrypt ($ str, 'e', $ key); echo 'encryption :'. encrypt ($ str, 'e', $ key); echo 'decryption :'. encrypt ($ str, 'D', $ key );