sau412/provably_fair

Faucet with provably fair games

provably_fair's Issues

Security certificate expired

The website’s security certificate expired on July 5th 2023

Provably unfair

Consider the function:

function get_roll_result($server_seed,$user_seed) {
        $hash=hash("sha256","$server_seed.$user_seed");
        $bytes=substr($hash,0,8);
        $number=hexdec($bytes);
//return $number;
        $roll=round($number/429496.7295);
        $roll=sprintf("%05d",$roll);
        return $roll;
}

There are two issues with this code that make it unfair (ie. not uniform between [0-10000]). First is the use of round. $number/429496.7295 returns a real number between 0 and 10000 inclusive. If we assume is uniformly distributed, then a 0 or 10000 are both half as likely to be rolled than any other number. 0 is only selected if the input falls in [0,0.5), and 1000 only if [9999.5, 10000], where as a number like 1 could result from any input between [0.5, 1.5).

Secondly, $number/429496.7295 is not uniformly distributed. It only consists of values that are a multiple of 1/429496.7295, which can potentially mean an uneven amount of numbers will map to a particular interval if that interval is not also a multiple of 1/429496.7295. For instance, with the current round scheme, 429497 values for $bytes map to 1, while 429496 values map to 2.

May I suggest this alternative algorithm which fixes the above issues, but is slightly more computationally expensive and difficult to validate manually:

function get_roll_result($server_seed,$user_seed) {
    for ($i = 0;;$i++) {
        $hash=hash("sha256","$server_seed.$user_seed.$i");
        $bytes=substr($hash,0,8);
        $roll=hexdec($bytes) % 16384;
//return $roll;
        if ($roll <= 10000) {
            return $roll;
        }
    }
}

Overdrawn balance

By making multiple withdraw requests for the total wallet amount, the wallet balance can be overdrawn.

free roll via email not working with protonmail.ch

@sau412 free roll via email not working

Faucet no longer functioning properly (phantom rolls)

On https://freegridco.in/#free_roll, the page persistently displays Wait for xx:xx before next roll, even if I haven't been to the page in hours. It seems the system believes rolls were made that weren't, the balance doesn't increment, and clicking "view last roll seeds" shows the last roll was made two days ago.

If I leave the page open until the roll button appears and click it, it's replaced by red error text stating Only one roll in 3600 seconds allowed. Wait xxxx seconds more..

MFA - 2FA

Can someone put MFA on the login please? This would be great to prevent being hacking into.

Exchange tab stoped working

The Exchange tab of freegridco.in is not working. After clicking on it nothing happens.

Transaction stuck as pending

transaction id is 9563f42780cdecc45d2df54a1ec3592534813109fe5ce68f2674368f0976a7f0

.onion server answers 504

When accessing the .onion server, Tor browser returns error: 504 Gateway Time-out

Send and receive error

Query error: SELECT SUM(spent) FROM lotto_tickets WHERE user_uid='xxx'

referal link pls

pls do add referal link.pls ..so i can invite more to your website ..thanks.