在 PHP 中使用 XOR 加密/解密
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Encrypt/decrypt with XOR in PHP
提问by JoeNguyen
I am studying encryption. And I got a problem like this:
我正在研究加密。我遇到了这样的问题：
After I XOR plaintext with a key, I get a crypt, "010e010c15061b4117030f54060e54040e0642181b17", as hex type. If I want to get plaintext from this crypt, what should I do in PHP?
在我用密钥对明文进行异或之后，我得到一个 crypt，“010e010c15061b4117030f54060e54040e0642181b17”，作为十六进制类型。如果我想从这个 crypt 中获取明文，我应该在 PHP 中做什么？
I tried convert it to string/int and after that take them to XOR with the key (three letters). But it doesn't work.
我尝试将其转换为字符串/整数，然后将它们与密钥（三个字母）进行异或。但它不起作用。
This is the code:
这是代码：
function xor_this($string) {
// Let's define our key here
$key = 'fpt';
// Our plaintext/ciphertext
$text = $string;
// Our output text
$outText = '';
// Iterate through each character
for($i=0; $i<strlen($text); )
{
for($j=0; $j<strlen($key); $j++,$i++)
{
$outText .= ($text[$i] ^ $key[$j]);
//echo 'i=' . $i . ', ' . 'j=' . $j . ', ' . $outText{$i} . '<br />'; // For debugging
}
}
return $outText;
}
function strToHex($string)
{
$hex = '';
for ($i=0; $i < strlen($string); $i++)
{
$hex .= dechex(ord($string[$i]));
}
return $hex;
}
function hexToStr($hex)
{
$string = '';
for ($i=0; $i < strlen($hex)-1; $i+=2)
{
$string .= chr(hexdec($hex[$i].$hex[$i+1]));
}
return $string;
}
$a = "This is the test";
$b = xor_this($a);
echo xor_this($b), '-------------';
//
$c = strToHex($b);
$e = xor_this($c);
echo $e, '++++++++';
//
$d = hexToStr($c);
$f = xor_this($d);
echo $f, '=================';
And this is the result:
这是结果：
This is the test-------------
PHP Notice: Uninitialized string offset: 29 in C:\ Users\Administrator\Desktop\test.php on line 210 PHP Stack trace: PHP 1. {main}() C:\Users\Administrator\Desktop\test.php:0 PHP 2. xor_this() C:\Users\Administrator\Desktop\test.php:239
Notice: Uninitialized string offset: 29 in C:\Users\Administrator\Desktop\test.p hp on line 210
Call Stack: 0.0005 674280 1. {main}() C:\Users\Administrator\Desktop\test.php:0 0.0022 674848 2. xor_this() C:\Users\Administrator\Desktop\test.php:23 9
UBE^A?WEAVA?WEAV@?WEARAFWECWB++++++++
This is zs$fs?=================
这是测试-------------
PHP 注意：未初始化的字符串偏移量：29 in C:\Users\Administrator\Desktop\test.php on line 210 PHP Stack trace: PHP 1. {main}() C:\Users\Administrator\Desktop\test.php:0 PHP 2. xor_this() C:\Users\Administrator\Desktop\test.php:239
注意：未初始化的字符串偏移量：29 in C:\Users\Administrator\Desktop\test.p hp on line 210
调用堆栈：0.0005 674280 1. {main}() C:\Users\Administrator\Desktop\test.php:0 0.0022 674848 2. xor_this() C:\Users\Administrator\Desktop\test.php:23 9
UBE^A?WEAVA?WEAV@?WEARAFWECWB++++++++
这是 zs$fs？==================
Why? The "UBE^A?WEAVA?WEAV@?WEARAFWECWB++++++++" is the result, which I got trouble in my real work.
为什么？结果是“UBE^A?WEAVA?WEAV@?WEARAFWECWB++++++++”，我在实际工作中遇到了麻烦。
回答by One Man Crew
Try this:
尝试这个：
function xor_this($string) {
// Let's define our key here
$key = ('magic_key');
// Our plaintext/ciphertext
$text = $string;
// Our output text
$outText = '';
// Iterate through each character
for($i=0; $i<strlen($text); )
{
for($j=0; ($j<strlen($key) && $i<strlen($text)); $j++,$i++)
{
$outText .= $text{$i} ^ $key{$j};
//echo 'i=' . $i . ', ' . 'j=' . $j . ', ' . $outText{$i} . '<br />'; // For debugging
}
}
return $outText;
}
Basically to revert text back (even numbers are in) you can use the same function:
基本上要恢复文本（偶数在），您可以使用相同的功能：
$textToObfuscate = "Some Text 12345";
$obfuscatedText = xor_this($textToObfuscate);
$restoredText = xor_this($obfuscatedText);
回答by lalala
Even easier:
更简单：
function xor_string($string, $key) {
for($i = 0; $i < strlen($string); $i++)
$string[$i] = ($string[$i] ^ $key[$i % strlen($key)]);
return $string;
}
回答by Stalingrad
Based on the code above i created 2 functions to xor encode a JSON string using javascript and then decode it on server side using PHP.
基于上面的代码，我创建了 2 个函数来使用 javascript 对 JSON 字符串进行异或编码，然后使用 PHP 在服务器端对其进行解码。
!!! Important:If you will have characters different from ASCII(like Chinese, Cyrillic, Symbols...) in your JSON string, you must eitherwrite some code in PHP or JS to fix how these characters are encoded/decoded (ord/chr in PHP produce different results in comparison with JS charCodeAt/String.fromCharCode) orjust base64_encode the JSON string and after that xor encode it.
！！！重要提示：如果你会在你的JSON字符串有不同的ASCII（如china，西里尔字母，符号...）字符，则必须要么写在PHP或JS的一些代码来解决这些字符是如何编码/解码（ORD / CHR在与 JS charCodeAt/String.fromCharCode) 相比，PHP 会产生不同的结果，或者只是 base64_encode JSON 字符串，然后对其进行异或编码。
Personally i use xor_string(base64_encode(JSON.stringify(object)), 'xor_key')in JS and on PHP side:
我个人xor_string(base64_encode(JSON.stringify(object)), 'xor_key')在 JS 和 PHP 端使用：
$json = json_decode(base64_decode(
xor_string(file_get_contents("php://input"), 'xor_key')
),
true);
PHP:
PHP：
function xor_string($string, $key) {
$str_len = strlen($string);
$key_len = strlen($key);
for($i = 0; $i < $str_len; $i++) {
$string[$i] = $string[$i] ^ $key[$i % $key_len];
}
return $string;
}
Javascript:
Javascript：
function xor_string(string, key) {
string = string.split('');
key = key.split('');
var str_len = string.length;
var key_len = key.length;
var String_fromCharCode = String.fromCharCode;
for(var i = 0; i < str_len; i++) {
string[i] = String_fromCharCode(string[i].charCodeAt(0) ^ key[i % key_len].charCodeAt(0));
}
return string.join('');
}
