Working of freebitco.in site

SEEDS FOR YOUR NEXT ROLL

Server Seed Hash (SHA-256)
Client Seed
Nonce	43960

PREVIOUS ROLL DETAILS

Server Seed Hash (SHA-256)
Server Seed
Client Seed
Nonce	43959
Rolled Number	3715

CLICK HERE TO VERIFY YOUR ROLLS

This game is provably fair. What that means is that there is no way the site can cheat you by picking a number that is in our favour.

The way this works is that each roll is calculated using 3 parameters - the server seed, client seed and nonce. Out of these, we show you the client seed and nonce that will be used for your next roll along with a SHA256 hash of the server seed. You can also change the client seed if you wish. The server seed is the only part that is kept a secret until after the roll.

Then after you roll, under the section titled PREVIOUS ROLL DETAILS, we show you the server seed that was used and you can verify that this was the same server seed that we said we were going to use before the roll by checking if the SHA256 hash of this seed matches the SHA256 hash that we showed you before the roll.To know exactly how we calculate the rolls, read the section below titled How are rolls calculated?

After you roll, you can also click the link above named CLICK HERE TO VERIFY YOUR ROLLS to verify your roll using our javascript based roll verifier which uses the same seeds to re-calculate the roll right in your browser without any external communication.

How are rolls calculated?

1. Two strings are created : 
   STRING1 = "[NONCE]:[SERVER SEED]:[NONCE]" 
   STRING2 = "[NONCE]:[CLIENT SEED]:[NONCE]"
   For your last roll : 
   STRING1 = "43959:e4854eb6773b3bc9341611edcb29ea9d39ffcb7ede76a8844f7650e37c581697:43959" 
   STRING2 = "43959:qpbcio47aaJx7OE7:43959"
2. Then HMAC-SHA512 is used to hash STRING1 with STRING2 as the secret key, giving us a 128 character hex string.
3. The first 8 characters of the hex string are taken and converted to a decimal.
4. This decimal is then divided by 429496.7295 and rounded off to the nearest whole number.
5. This whole number is used as your roll, with the maximum possible value being 10,000.