Golden

Generate String from Seed

How the Random String Is Generated

Every day, a new random seed is created and saved. This seed is a unique secret string used as the foundation for generating the winning string.

The function below takes that seed and turns it into a consistent, secure string using HMAC SHA256 hashing. The same seed will always generate the same string, ensuring fairness and verifiability.

Here's how it works step-by-step:

1. A list of allowed characters (0–9, a–z, A–Z) is defined.
2. We loop as many times as the desired string length (e.g. 6 characters).
3. Each loop adds the loop index to the seed, hashes it using HMAC-SHA256, and selects a character based on the hash.
4. The result is a consistent, pseudo-random string from the original seed.

PHP Code:

function generate_random_string_from_seed($seed, $length) {
    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $characters_length = strlen($characters);
    $random_string = '';

    for ($i = 0; $i < $length; $i++) {
        $input = $seed . pack('N', $i);
        $hash = hash_hmac('sha256', $input, $seed, true);
        $random_string .= $characters[ord($hash[0]) % $characters_length];
    }

    return $random_string;
}

🔒 This method ensures that the result is unpredictable until the seed is revealed, and once revealed, anyone can verify it by re-running the function with the seed.