What is BitDouble?

BitDouble is a platform for unique games to gamble with Bitcoin. We are currently offering two games on our site and are planning on adding more in the future. You can either play versus the house or against other players.

You can read games rules on about page.

All our games are provably fair – ensuring a fair play each and every time.

What is a mBit ()?
All values on this website are denominated in mBit and one mBit equals 1/1000th of a Bitcoin. This was done because entering bets in Bitcoin would be tiresome with all the decimal places to keep track of.
How many confirmations do the deposits need?

Depending on the size of the deposit we require 1 or 2 confirmations. Our system needs to wait for blockchain confirmations before the Bitcoin is added to your account balance. Usually a confirmation takes about 10 minutes, but this is an average value and can be much faster or slower.

Go to your Deposit page to see how many confirmations are needed and how many you already have. If the deposit has many confirmations and was still not added to your account, please contact support.

I made a Bitcoin deposit and it's not showing on the deposit history. Where is it?
If you made a deposit and it isn't showing up on the Deposit page after a few minutes, try checking if you can find the transaction using a blockexplorer like blockchain.info If the deposit was sent correctly, then please contact support.
What limits does Roulette have? How much can I win with a roulette?

The maximum bet you can place on roulette is 500 (0.5 ) and if you place a bet on green you can win 500*14 = 7000 (7 ). These limits will be raised gradually in the future.

The minimum bet is 0.001 .

What limits does Coin Flip game have?

The maximum bet you can place on coin flip duel is 500 (0.5 ) and you can win 500*2 - 3% = 970 (0.97 ).

The minimum bet is 0.1 .

Do you have a faucet?

Yes, you can claim 0.005 per hour if your balance is zero.

What are your VIP levels?

We are awarding our high volume players with a certain badge of honor depending on his VIP level. Their avatar will receive a bronze, silver, gold or diamond outline with beautiful design to showcase their achievements.

Also you get a significant bonus for achieving each level.

There are ten VIP levels and you can reach then with the following wager requirements:

Level Wager Requirement Bonus
VIP 1 VIP Level 1 Bronze > 100.0 1.0
VIP 2 VIP Level 2 Bronze > 500.0 5.0
VIP 3 VIP Level 3 Bronze > 1500.0 15.0
VIP 4 VIP Level 4 Bronze > 5.0 50.0
VIP 5 VIP Level 5 Silver > 15.0 150.0
VIP 6 VIP Level 6 Silver > 50.0 0.5
VIP 7 VIP Level 7 Gold > 150.0 1.5
VIP 8 VIP Level 8 Gold > 500.0 5.0
VIP 9 VIP Level 9 Diamond > 1500.0 15.0
VIP 10 VIP Level 10 Diamond > 5000.0 50.0

As you can see the higher VIP levels are very hard to obtain and only the biggest whales will be able to reach it! A true badge of honor.

What is the roulette auto-betting feature?
We have created a very simple but powerful feature for our customers that allows them to easily «program» their roulette betting strategies and then let the bot place the bets for them. For example if you want to double the bet each time you lose and return to the basebet once you win (martingale) then it only takes you few clicks to program this!
What is «One-click Signup»?
With this feature you can create an account with one click. This means it will give you a random username and password that you can find in your Settings. If you don't save these login data and delete your cookies/close your private browsing page, your account will be lost and can't be restored by our support team!
Can I change the nickname if I don't like it anymore?
This is not yet possible, but in the future you will be able to do that.
What is Provably Fair?

Provably fair is a way of generating random numbers using cryptography such that the results can be verified by a third party. This means the operators cannot manipulate the outcome of any game.

In short, for roulette we use the results of the Bitcoin blockchain to seed our RNG (random number generator) – for a detailed explanation see below.

Provable fairness has been verified by TheBitcoinStrip.

How does it work for Roulette game?

Each roll is computed using the SHA-256 hash of 3 distinct inputs.

First, is the server seed. This is a precomputed value generated by BitDouble some time in the past. Seeds are generated in a chain such that today's seed is the hash of tomorrow's seed. Since there is no way to reverse SHA-256 we can prove each seed was generated in advance by working backwards from a precomputed chain.

seed 0 => seed 1 => seed 2 => seed 3

Next, the server seed is salted (scrambled) with the last 16 bytes of the hash of the last Bitcoin block with height equal to the largest height divisible by 100, which has at least 7 confirmations.

Finally, each roll is salted with the unique round id ensuring a different hash each roll.

The round's hash is generated using SHA256("serverseed-salt-roundid"). Taking the first 16 hex digits of the resulting hash and converting to decimal yields an integer from 0-2^64. Taking modulo 15 yields the final roll in the range 0-14.

A JS implementation of the aforementioned process is included on Provable Fair page.

How do I verify a roulette roll?

On our Provable Fair page we added a script that you can use to check rolls.
You can also download JS script and check it.

How do I verify a coin flip duel result?

We have a Provable Fair for Coin Flip Duels page.

Users do not get the secret until duel is finished, but you know the outcome and secret hash when you start new duel or join a duel waiting to start.

How does the affiliate system work?

The affiliate system lets anyone earn credits by referring new players to the site. Visit the affiliate dashboard to find your unique referral code. Share with friends, in forum signatures, or on social media. Please don't spam your link, otherwise we might have to close your account!

When new players use your referral code they'll get 0.005 FREE after e-mail confirmation. And you'll earn credits every time your referrals place a bet – regardless if they win or lose.

What is affiliate level?

Your affiliate level determines how much (%) you'll earn from each referral's bet. Your affiliate level is determined by the amount of volume your players made.

You can read more about Volume Affiliate Levels on Affiliate program page.