Need very simple encryption for URLs ...

[doa24uk]

Hi guys,

 

I need a very simply encryption algorithm, it will be used to encrypt (effectively hide) the actual URLs

 

basically turning

 

http://none.com

 

into something like this

 

f2kj932fj923fff

 

so my URL (and hence what the user gets to see is the following)

 

http://mysite.com/?myvar=f2kj932fj923fff

 

Instead of this -->

 

http://mysite.com?myvar=http://none.com

 

I must be able to decode this string back to it's plain text with a seperate script though....

 

 

[gevans]

You could take a look at mcrypt

 

http://uk3.php.net/manual/en/book.mcrypt.php

[doa24uk]

Sorry, I should have mentioned that I've tried several mcrypt algo's but my urls seem to be too long - they always cut off / stop decrypting at 32 characters.

 

 

// Encrypt Function
function mc_encrypt($encrypt, $mc_key) {
   $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND);
   $passcrypt = trim(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $mc_key, trim($encrypt), MCRYPT_MODE_ECB, $iv));
   $encode = base64_encode($passcrypt);
   return $encode;
}

// Decrypt Function
function mc_decrypt($decrypt, $mc_key) {
   $decoded = base64_decode($decrypt);
   $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND);
   $decrypted = trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $mc_key, trim($decoded), MCRYPT_MODE_ECB, $iv));
   return $decrypted;
}

$key = 'something';
$message = 'http://mysite.com/4329358521903853209358305219835210352185321095900-making-this-long-to-test-length';

$encrypted = mc_encrypt($message, $key);
$decrypted = mc_decrypt($encrypted, $key);


echo "Encrypted = " . $encrypted . "<br /><br />";
echo "Original message for reference = . $message .<br /><br />";
echo "Decrypted = " . $decrypted . "<br /><br />";

[gevans]

I guess you could take something really simple, like the character and its index position in the variable, substitute it from another array... easily reversable

[gevans]

Or you could use something like base64_encode()

 

http://us3.php.net/manual/en/function.base64-encode.php

 

example

 

<?php

echo $foo = 'http://www.google.co.uk';

echo '<br /><br />';

echo base64_encode($foo);

[Daniel0]

You could also implement a simple shifting like the XOR cipher.