[SOLVED] MD5 base64_encode help.

[Crew-Portal]

Quick question about encription. Is there a way of encoding information and then having a relable way of decoding it? Preferable with a easter egg. Such as:

 

$encoded_string = "Testing".$secretword;

 

I tried using base64_encode and _decode, and it worked perfectly. The only problem is that the string length is not constant. I need a way of encoding so that the length is always the same.. 4 Charactors.. 50 Charactors. It doesnt matter, It just has to be constant. So that "test" and "Hello my name is billy bob joe" Would both encode with a str length of like.. 18. You know what I mean?

[Mark Baker]

So you're after a method of encoding data where the single character string "A" and a 10MB binary document would both encrypt to the same size. Such a creature doesn't exist, for pretty obvious reasons.

 

But can you explain exactly why you think you need this?

[phporcaffeine]

I'm not sure what your trying to do either but this is an example of basic XOR and base_64 encryption:

 

<?php

function XOREncryption($InputString, $KeyPhrase){

    $KeyPhraseLength = strlen($KeyPhrase);

    // Loop trough input string
    for ($i = 0; $i < strlen($InputString); $i++){

        // Get key phrase character position
        $rPos = $i % $KeyPhraseLength;

        // Magic happens here:
        $r = ord($InputString[$i]) ^ ord($KeyPhrase[$rPos]);

        // Replace characters
        $InputString[$i] = chr($r);
    }

    return $InputString;
}

//SALT
$salt = 'my_special_phrase';

//ENCRYPT
$crypted = XOREncryption('my string', $salt);

//DECRYPT
$decrypted  = XOREncryption($crypted, $salt);

?>

[Crew-Portal]

That works great phpORcaffine. But why cant I echo $crypted?

[phporcaffeine]

Try this one .... I pulled the function out of some code that I was building and my head was in 5 different spots ... I didn't get it all.  Here you go:

 

<?php

   function XOREncryption($InputString, $KeyPhrase){
    
       $KeyPhraseLength = strlen($KeyPhrase);
    
       // Loop trough input string
       for ($i = 0; $i < strlen($InputString); $i++){
    
           // Get key phrase character position
           $rPos = $i % $KeyPhraseLength;
    
           // Magic happens here:
           $r = ord($InputString[$i]) ^ ord($KeyPhrase[$rPos]);
    
           // Replace characters
           $InputString[$i] = chr($r);
       }
    
       return $InputString;
   }

//SALT
$salt = 'my_special_phrase';

//ENCRYPT
$crypted = base64_encode(XOREncryption('my string', $salt));
echo "Encrypted: " . $crypted . "<br />";

//DECRYPT
$decrypted  = XOREncryption(base64_decode($crypted), $salt);
echo "Decrypted: " . $decrypted;

?>

[Crew-Portal]

Beautiful. Thanks alot man