🪨Immutable Outcomes

How Dumont's immutable outcome mechanism works.

One of the primary differences between Dumont and conventional gambling platforms is that Dumont ensures game outcomes are cryptographically and, thus, provably immutable.

This critical feature prevents operators from manipulating outcomes, fostering a fair environment where gamblers can reliably test their luck.

To achieve this, we have designed a simple yet powerful commit-reveal mechanism that leverages blockchain immutability and the uniqueness of hashing algorithm outputs.

How it works

• Step 1- Encryption and operator commitment

When you create a round, you essentially create a dataset consisting of 52 hashes corresponding to a random arrangement of the 52 cards in a standard deck that will be stored in the blockchain.

The hashes are generated by encrypting the card face along with a salt, which is a string of characters the operator uses in encrypting the card face. These hashes will be used to verify the operator’s commitment to data integrity.

For the calculation purposes by the smart contract, we've assigned numbers to the card faces:

Card	Number	Card	Number
Ace of Hearts	0	Ace of Diamonds	26
Two of Hearts	1	Two of Diamonds	27
Three of Hearts	2	Three of Diamonds	28
Four of Hearts	3	Four of Diamonds	29
Five of Hearts	4	Five of Diamonds	30
Six of Hearts	5	Six of Diamonds	31
Seven of Hearts	6	Seven of Diamonds	32
Eight of Hearts	7	Eight of Diamonds	33
Nine of Hearts	8	Nine of Diamonds	34
Ten of Hearts	9	Ten of Diamonds	35
Jack of Hearts	10	Jack of Diamonds	36
Queen of Hearts	11	Queen of Diamonds	37
King of Hearts	12	King of Diamonds	38
Ace of Spades	13	Ace of Clubs	39
Two of Spades	14	Two of Clubs	40
Three of Spades	15	Three of Clubs	41
Four of Spades	16	Four of Clubs	42
Five of Spades	17	Five of Clubs	43
Six of Spades	18	Six of Clubs	44
Seven of Spades	19	Seven of Clubs	45
Eight of Spades	20	Eight of Clubs	46
Nine of Spades	21	Nine of Clubs	47
Ten of Spades	22	Ten of Clubs	48
Jack of Spades	23	Jack of Clubs	49
Queen of Spades	24	Queen of Clubs	50
King of Spades	25	King of Clubs	51

When you create a round, the operator uses a cryptographic algorithm to hash the round’s arrangement of card number and store them in the blockchain:

$$hash = keccak256(abi.encodePacked(number, salt))$$

For example, here is the data for card 1 on the table (only the operator has this information, which will be shown later).

• Card number: 50

• Salt: 0x29b2846437e56f8131b88e54985cdc9d0b70a743441bce290ebb0d26b969bd17

So its hash will be

0xee55120428f63b8d756ebb48c112e5b32ee3763dcf1f37061fc0d361ea29d214

This hashing task happened for each card; for example, here's a sample data set for a deck of cards in a round.

Card 1: 0xee55120428f63b8d756ebb48c112e5b32ee3763dcf1f37061fc0d361ea29d214 Card 2: 0x6f3597dfd6cf142f4866b1fb423304ce0c73148a2d96d0c875dd8fee48519e01 Card 3: 0x45c3c5e9b021b42da951d4e6611e3d449aab4fd974cfec82e4788c2165642437 . . Card 52: 0x734536389ac51af499942b4d03ec873fbc2b0e91879eaaf58bca5b266d393963

• Step 2 - Verification and operator integrity

When a player guesses the value of a card and submits their choice to the blockchain, the operator should send that game's card number and salt to the smart contract.

Then, the smart contract verifies the authenticity of the salt and card number the operator sends to the contract by matching their hash with the stored card hash in the blockchain.

Now, three possible scenarios would follow that guarantee no wrong-doing by the operator:

• The operator sends the correct salt and card number. If everything is in place, the system determines the winner based on the player's choice values and the card's actual face value.

• The operator sends incorrect salt or card number: If the operator sends the wrong salt or card number for whatever reason, the smart contract declares the player as the bet winner so that they can claim their win.

• The operator fails to send salt and card number: Technically, the operator has 6 hours to submit the card’s salt and card number to the blockchain. If, for whatever reason, the operator fails to do so, the smart contract declares the player as the bet winner so that they can claim their win.

As you can see, the player bears no risks of getting manipulated, and all the responsibility for security and integrity falls on the shoulders of the operator.

Let’s consider an example game: Imagine a player guesses Card 3's value on the table is 5 and sends this guess to the blockchain. Now, the operator sends the corresponding card number and salt to the contract.

Suppose the card’s data are as follows:

• Salt: 0x39f3a5662ea8d8e313deebc73cba8578c275c7a267bd95af31ed428f543aef33

• Card number: 24 (Queen of Spades)

The resulting hash calculated by the contract is:

0x45c3c5e9b021b42da951d4e6611e3d449aab4fd974cfec82e4788c2165642437

If this hash matches the one stored for that card in the blockchain during round creation, the smart contract will verify the operator's data integrity.

In this example, the hash matches, so the operator performed their work correctly.

• Step 3 - Result determination and payout

After the operator’s integrity is established, the game's outcome is determined based on the user's choices. If the user correctly guesses the card, the smart contract automatically sends the winning amount to the player's address.

In the above example, the player chose 5 as the card value, but the actual card value was queen, so they lost.

Trust the code, not the human: All the rules and processes mentioned above are encoded in a non-upgradable smart contract, and no one can prevent its execution.