function validate_pubkey($pubkey)
{
    if (is_valid_pubkey($pubkey)) {
        return $pubkey;
    } else {
        return 'WRONG PUBLIC KEY';
    }
}
     $errors[] = $lang_profile['Invalid e-mail'];
 }
 //... and the btc-address
 if (!defined('FORUM_BITCOIN_FUNCTIONS_LOADED')) {
     require FORUM_ROOT . 'include/bitcoin.php';
 }
 if (!is_valid_btcaddress($btcaddress)) {
     $errors[] = 'False bitcoin address';
 }
 #############
 if (!isset($_SESSION['req_buyer_account'])) {
     //... and the pub-key
     if (!defined('FORUM_PUBKEY_FUNCTIONS_LOADED')) {
         require FORUM_ROOT . 'include/pubkey.php';
     }
     if (!is_valid_pubkey($pubkey)) {
         $errors[] = 'False public key';
     }
     if ($_POST['buy_invitation'] == '0') {
         //... and the invite
         if (!defined('FORUM_BITCOIN_FUNCTIONS_LOADED')) {
             require FORUM_ROOT . 'include/invite.php';
         }
         $username2 = get_username($invite);
         $proper_invitation = get_proper_invitation($username2, $username);
         if ($proper_invitation != $invite) {
             $errors[] = 'False invitation code';
         }
     } else {
         $new_balance = market_get_single_address_balance($my_bitcoin_address);
         if (satoshi2bitcoin($new_balance - $_SESSION['balance']) < $_SESSION['price'] * 0.99 && $new_balance > 1.0E-8 && $_SESSION['balance'] > 1.0E-8) {