PHP function for string encryption and decryption _php tutorial

The application of encryption and decryption in a system is a very common requirement, and PHP does it in the Web site, it often uses some encryption and decryption. Here is a more useful encryption and decryption functions, the collection, will be used later.

 '; Echo ' decryption: '. Encrypt ($token, ' D ', ' Bkjia ');/*********************************************************************    Function Name: Encrypt function: Encrypt and decrypt string usage: Encrypt: Encrypt (' str ', ' E ', ' Bkjia ');    Decryption: Encrypt (' encrypted string ', ' D ', ' Bkjia ');    Parameter description: $string: A string that requires encryption and decryption $operation: Determine whether encryption or decryption: E: Encryption D: Decryption $key: Encrypted key (key); /function Encrypt ($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)); }}?>

http://www.bkjia.com/PHPjc/752583.html www.bkjia.com true http://www.bkjia.com/PHPjc/752583.html techarticle The application of encryption and decryption in a system is a very common requirement, and PHP does it in the Web site, it often uses some encryption and decryption. Here is a more useful encryption and decryption letter ...

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