ActuallyFair.com

sequenceDiagram actor Player participant GS as Game Server participant VX as Verified By Note over GS: The game server needs a secret for game generation GS->>GS: GS_SEED := random_256_bits() Note over GS: Makes a commitment to it GS->>GS: GS_COMMITMENT := sha256(GS_SEED) Note over GS, VX: The game server sends its commitment GS->>VX: vx.make_commitment(GS_COMMITMENT) Note over VX: VX records this, and returns a public key (using BLS) VX-->>GS: VX_PUBKEY Note over GS, Player: The player is given what it needs to verify games<br>(in the future) GS->>Player: GS_COMMITMENT, VX_PUBKEY Note over Player: The player can record this, and picks their own<br>PLAYER_SEED to influence games Player->>GS: PLAYER_SEED GS->>GS: NONCE := 0 loop Each Bet Note over Player: The player makes a wager Player->>GS: WAGER Note over GS: The Game Server calculates its unpredictable contribution to the game result GS->>GS: GS_CONTRIBUTION := HMAC.SHA256(GS_SEED, PLAYER_SEED || ':' || NONCE) Note over GS,VX: The game server requests the final piece of information<br> needed to construct a bet outcome GS->>VX: vx.make_message(GS_COMMITMENT, GS_CONTRIBUTION, WAGER) Note over VX: VX records the details of this wager VX->>VX: VX_SIGNATURE := bls.sign(GS_CONTRIBUTION, VX_PRIVATE_KEY) VX-->>GS: VX_SIGNATURE Note over GS: Should make sure VX is not cheating GS->>GS: bls.verify(VX_SIGNATURE, GS_CONTRIBUTION, VX_PUBKEY) Note over GS,VX: Can derive wager results from<br> VX_SIGNATURE, Wager GS-->>Player: Wager Result GS->>GS: NONCE := NONCE + 1 end Player->>GS: Please reveal your secret Note over GS: The Game Server must be careful to never use this seed again GS-->>Player: GS_SEED Note over Player: Player can now verify all games Note over GS, VX: VX would also like to know the GS_SEED<br>so it can also a player-oriented verification GS->>VX: vx.make_reveal(GS_SEED)