Why is the winning number pre-generated and immutable? Because we use the MD5 hash algorithm, which is irreversible and unique. Before each round begins, we combine the winning number and a secret key to form an encryption seed (in the format of "winning number:secret key"), and then generate a hash string using the MD5 algorithm, which is published in advance. Changing any character in the encryption seed will result in a different hash string. Given the foreseeable level of computational power available to humans, no one (including us) can find another encryption seed that produces the same hash string. Therefore, this proves that our game is completely fair and cannot be cheated. Anyone can verify the hash string by searching for an MD5 encryption website on Google.