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This is not about security. It is also not to make it hard to break. I'm looking for a simple algorithm to change a string (a url) in a way it does not resemble the original. The encryption will be done with javascript. Then I want to feed the encrypted string to a PHP function to change it back to the original. Both ends could share a secret key, or the conversions could be key-less and rely on just logic.
The ideal solution
Edit: The last requirement was added after shamittomar's answer.
544
You can use bitwise XOR in javascript to encode the string and again in PHP to decode it again. I wrote a little Javascript example for you. It works the same in PHP. If you call enc() a second time with the already encoded string, you'll get the original string again.
<html>
<head><title></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>
In PHP do something like this (caution, this is not tested and it's been a long while since I did 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;
If that's what you want, you can Base64 encode and decode that.
[EDIT]: After OP clarification:
As you do not want widely used methods, here is one rarely used method and that can do it for you by giving output only in LOWERCASE letters and NUMBERS. It is Base32 Encode/Decode. Use the following libraries:
34
If it's not about security, and not about making it hard to break, then how about ROT-13?
//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/string/rot13 [rev. #1]
String.prototype.rot13 = function(){
return this.replace(/[a-zA-Z]/g, function(c){
return String.fromCharCode((c <= "Z" ? 90 : 122) >= (c = c.charCodeAt(0) + 13) ? c : c - 26);
});
};
...
var s = "My String";
var enc = s.rot13(); // encrypted value in enc
PHP has a native function, str_rot13: http://php.net/manual/en/function.str-rot13.php
$decrypted = str_rot13($_GET['whatever']);
Well I found this page and found Redcully's program not work for me so I thought It happens with all others. finally I got reason and fixed it. Here new code is... Thanks to Redcully :)
function encode(str) {
var encoded = "";
for (i=0; i<str.length;i++) {
var a = str.charCodeAt(i);
var b = a ^ 51; // bitwise XOR with any number, e.g. 123
encoded = encoded+String.fromCharCode(b);
}
return encoded;
}
function decode($encoded) {
$decoded = "";
for( $i = 0; $i < strlen($encoded); $i++ ) {
$b = ord($encoded[$i]);
$a = $b ^ 51; // <-- must be same number used to encode the character
$decoded .= chr($a);
}
return $decoded;
}
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