email - Xor Encryption PHP for Activationlink E-Mail -

i have problem xor encryption activiationlink. xor encryption activiationlink code works, encryption last id user. if im testing mail, produced curious encryption "30303030"

example id: 3445 if encryption have 54515c50

but if click on activationlink in e-mail have "30303030" , not 54515c50.

i don't know how creat encryption "30303030". testing id , have again "30303030" encryption

i don't have idea solve this.

here code:

<?php  // xor "encryption" function x0rcrypt($text, $key) {     if (strlen($schluessel) == 0) {         return;     }     $result = '';     $i = 0;     while ($i < strlen($text)) {         ($j=0; $j < strlen($key); $j++) {             if ($i >= strlen($text)) {                 break;             }             // text xor key             $result .= $text{$i} ^ $key{$j};             $i++;         }     }     return($result); }  // hex bin     function hex2bin($string) {     return pack('h*', $string); }  // encryption, return hex     function x0rencrypt($text, $key) {     return bin2hex(x0rcrypt($text, $key)); }  // decode, enter hex     function x0rdecrypt($text, $schluessel) {     return x0rcrypt(hex2bin($text), $schluessel); }  // example code: $text = 'blah blubb'; $key = 'geheimesganzlangesultrakompliziertespasswort';  // encryption #$text_encrypted = x0rencrypt($text, $key); // decode #$text_decrypted = x0rdecrypt($text_encrypted, $key);   ?> 

an here activationlink mail:

 $activlink="<a href=\"http://" . $_server['server_name'] ."/release/".rex_geturl('82','0', array('mode'=>x0rencrypt($db->last_insert_id, $key)), '&amp;'). "\">activation account</a>";