artygrand/decoder.php

## decoder.php
<?php

$encoded = "...";   // <-- encoded string from the request
$decoded = "";

for( $i = 0; $i < strlen($encoded); $i++ ) {
    $b = ord($encoded[$i]);
    $a = $b ^ 123;  // <-- must be same number used to encode the character
    $decoded .= chr($a)
}

echo $decoded;

## index.html
<html>
<head><title>Encoder</title></head>
<body>
<script type="text/javascript">
function enc(str) {
    var encoded = "";
    for (i=0; i<str.length;i++) {
        var a = str.charCodeAt(i);
        var b = a ^ 123;    // bitwise XOR with any number, e.g. 123
        encoded = encoded+String.fromCharCode(b);
    }
    return encoded;
}
var str = "hello world";
var encoded = enc(str);
alert(encoded);           // shows encoded string
alert(enc(encoded));      // shows the original string again
</script>
</body>
</html>
	<?php

	$encoded = "..."; // <-- encoded string from the request
	$decoded = "";

	for( $i = 0; $i < strlen($encoded); $i++ ) {
	$b = ord($encoded[$i]);
	$a = $b ^ 123; // <-- must be same number used to encode the character
	$decoded .= chr($a)
	}

	echo $decoded;
	<html>
	<head><title>Encoder</title></head>
	<body>
	<script type="text/javascript">
	function enc(str) {
	var encoded = "";
	for (i=0; i<str.length;i++) {
	var a = str.charCodeAt(i);
	var b = a ^ 123; // bitwise XOR with any number, e.g. 123
	encoded = encoded+String.fromCharCode(b);
	}
	return encoded;
	}
	var str = "hello world";
	var encoded = enc(str);
	alert(encoded); // shows encoded string
	alert(enc(encoded)); // shows the original string again
	</script>
	</body>
	</html>