Detailed explanation of examples of classic encryption methods for discuz content in PHP encryption-PHP Tutorial-php.cn

The example in this article describes the classic encryption method of discuz content in PHP encryption. Share it with everyone for your reference, the details are as follows:

Introduction: Sometimes, we want to encrypt certain sensitive fields in the table. We have thought about it for a long time but there is no better solution. The background is online I checked it out and found that this solution from the discuz forum can solve this situation well. I specially copied it and shared it with you. The code is as follows:

header ( "Content-type:text/html;charset=UTF-8" ); echo $string='花园路888号'; echo '
加密有效期10秒,密文内容:'; // $string='1111'; $sss=authcode($string,'','',10); echo $sss; echo '
加密后立即解密:...'; echo authcode($sss); sleep(6); echo '
6秒后解密...'; $aaaa=authcode($sss); var_dump($aaaa); sleep(5); echo '
再次5秒后解密...'; $aaaa=authcode($sss); var_dump($aaaa); /** * * @param string $string 明文或密文字符串 * @param string $operation DECODE表示解密,其它表示加密 * @param string $key 密钥 * @param int $expiry 密文有效期,0代码永不过期 * @return string */ function authcode($string, $operation = 'DECODE', $key = '', $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 ['discuz_auth_key'] ); // 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 == 'DECODE' ? substr ( $string, 0, $ckey_length ) : substr ( md5 ( microtime () ), - $ckey_length )) : ''; // 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 == 'DECODE' ? base64_decode ( substr ( $string, $ckey_length ) ) : sprintf ( '0d', $expiry ? $expiry + time () : 0 ) . substr ( md5 ( $string . $keyb ), 0, 16 ) . $string; $string_length = strlen ( $string ); $result = ''; $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 ($operation == 'DECODE') { // substr($result, 0, 10) == 0 验证数据有效性 // substr($result, 0, 10) - time() > 0 验证数据有效性 // substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, // 16) 验证数据完整性 // 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 ''; } } 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 ( '=', '', base64_encode ( $result ) ); } }

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The result of running the above code is:

花园路888号 加密有效期10秒,密文内容:ce9eelLd6jpd7hZJTRg+/fgg8cD9VG+1NsHvkavEKhdvhk7jcfDoQTYSAAw 加密后立即解密:...花园路888号 6秒后解密... string'花园路888号' (length=15) 再次5秒后解密... string'' (length=0)

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I hope this article will be helpful to everyone in PHP programming.

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