JS intercepts the string. The PHP string encryption function encrypts and restores the string within the specified time. It cannot be restored after timeout.

In this way, we can use this function for many purposes, such as: single sign-on token encrypted transmission, temporary password, etc.

Copy the code The code is as follows:

/**
* @param string $string original text or ciphertext
* @param string $operation operation (ENCODE | DECODE), default is DECODE
* @param string $key key
* @param int $expiry ciphertext validity period, when encrypted Valid, unit is second, 0 is permanently valid
* @return string The processed original text or the ciphertext processed by base64_encode
*
* @example
*
* $a = authcode('abc', 'ENCODE', ' key');
* $b = authcode($a, 'DECODE', 'key'); // $b(abc)
*
* $a = authcode('abc', 'ENCODE', 'key' , 3600);
* $b = authcode('abc', 'DECODE', 'key'); // Within one hour, $b(abc), otherwise $b is empty
* /
function authcode($string, $operation = 'DECODE', $key = '', $expiry = 3600) {
$ckey_length = 4;
// Random key length value 0-32;
// Add A random key can make the ciphertext irregular. Even if the original text and key are exactly the same, the encryption result will be different every time, making it more difficult to crack.
// The larger the value, the greater the ciphertext change pattern. The ciphertext change = 16 to the power of $ckey_length
// When this value is 0, no random key will be generated
$key = md5($key ? $key : EABAX::getAppInf('KEY'));
$keya = md5(substr($key, 0, 16));
$keyb = md5(substr($key, 16, 16));
$ keyc = $ckey_length ? ($operation == 'DECODE' ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$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.$keyb), 0, 16).$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( $result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {
return substr($result, 26);
} else {
return '';
}
} else {
return $keyc.str_replace('=', ' ', base64_encode($result));
}
}

The above introduces the PHP string encryption function that intercepts strings with js and encrypts and restores the string within a specified time. It cannot be restored after timeout, including the content of intercepting strings with js. I hope it will be helpful to friends who are interested in PHP tutorials.