本文实例讲述了PHP源码分析之DZX1.5加密解密函数authcode用法。分享给大家供大家参考。具体分析如下：
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PHP
$authkey = '';
/**
* @param string $string: 输入的需要加密（或解密）的明文（或密文）
* @param string $operation: 'DECODE'或其它，其中默认表示解密，输入其它表示加密
* @param string $key: 加解密密钥
* @param int $expiry: 有效期
*/
function authcode($string,$operation = 'DECODE',$key = '',$expiry = 0) {
global $authkey;
$ckey_length = 4;
$key = md5($key != '' ? $key : $authkey);
$keya = md5(substr($key,16));
$keyb = md5(substr($key,16,16));
$keyc = $ckey_length ? ($operation == 'DECODE' ? substr($string,$ckey_length): substr(md5(microtime()),-$ckey_length)) : '';
$cryptkey = $keya.md5($keya.$keyc);
$key_length = strlen($cryptkey);
$string = $operation == 'DECODE' ? base64_decode(substr($string,$ckey_length)) : sprintf('%010d',$expiry ? $expiry + time() : 0).substr(md5($string.$keyb),16).$string;
$string_length = strlen($string);
$result = '';
$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($operation == 'DECODE') {
if((substr($result,10) == 0 || substr($result,10) - time() > 0) && substr($result,10,16) == substr(md5(substr($result,26).$keyb),16)) {
return substr($result,26);
} else {
return '';
}
} else {
return $keyc.str_replace('=','',base64_encode($result));
}
}
$str = '1234';
$key = '1234';
echo "明文:".$str;
echo "
"; echo "密钥:".$key; $encode = authcode($str,'11',$key); echo "
"; echo "加密后的密文:".$encode; echo "
"; $decode = authcode($encode,'DECODE',$key); echo "解密后的明文:".$decode; /*End of PHP*/
"; echo "密钥:".$key; $encode = authcode($str,'11',$key); echo "
"; echo "加密后的密文:".$encode; echo "
"; $decode = authcode($encode,'DECODE',$key); echo "解密后的明文:".$decode; /*End of PHP*/
运行结果如下：
明文:1234 密钥:1234 加密后的密文:a52f67eXZGVy0HtQBo4vOREhq3WxnL6E2zlx75JGfoJW 解密后的明文:1234
希望本文所述对大家的PHP程序设计有所帮助。
