Beef PF

• client seed: a string chosen by the player (or automatically generated if you don't choose one)

• server seed: 64-character hex string generated using crypto.randomBytes(32) and hashed with SHA-256

• nonce: the number of round you're on, increases by 1 for every round across all house games

• cursor: internal number representing a nonce within the round, in beef there are 19 cursor values for each round and the cursor increases for each "shuffle" of the 0-19 sequence

• HMAC: cryptographic function that mixes unhashed server seed, client seed, nonce and cursor to produce a result

here's a 3rd party HMAC tool to verify each step for yourself: https://cryptii.com/pipes/hmac - (or any other one you prefer)

beef uses the "Fisher-Yates" shuffling method to shuffle numbers from 0-19, each corresponding to a "death point"

these are shuffled one by one for every round, with the "cursor" increasing for each shuffle, death points are already determined before your beef takes the first step, the outcome isn't influenced by how good you are at dodging cars

unhashed server seed: cb8bd577e2b1f62e91c0fe5296c145330bc8ae4307729a372aa4fe639a5af24c

client seed: 62OUyVeUGCRnTpU6

nonce: 9837

cursor: 0 (for the first shuffle)

here's what the "message" part of the HMAC looks like for calculating the first shuffle: <clientSeed:nonce:cursor> = 62OUyVeUGCRnTpU6:9837:0 (second shuffle would be 62OUyVeUGCRnTpU6:9837:1)

the "key" part is your unhashed server seed

if you're using the 3rd party site above to follow along it would look like this:

These values result in the following hexadecimal string:

225ddb7e98db55b0b5e30daaf4a20cd2a2c96bbf12b962a6e884f208789caa24

the first 4 bytes (8 hex characters) are used for shuffling, in this case "225ddb7e" - this value is converted from hexadecimal → decimal (225ddb7e → 576576382) then compared against the maximum fairness range, essentially so that 576576382 < 4,294,967,280 (largest of possible 32-bit values divisible by 20 to eliminate very small bias)

the decimal value from above is used to calculate which number to shuffle first: 576576382 % 20 = 2 (meaning if you divide x by 20, what number is left over)
​

the next shuffle uses 62OUyVeUGCRnTpU6:9837:1 as the "message" part, which gives 3205935593 as the decimal number

since the 20th slot is already decided, the calculation is 3205935593 % 19 = 5 ( the process continues like this, meaning the next shuffle would be x % 18 etc.)

the final sequence is then compared to death positions by difficulty level
(Extreme: 10, Hard: 5, Medium: 3, Easy: 1)

the round used as example had this set to "Extreme" which means 10 of the first numbers are arranged in ascending order and used as the final death positions

this gives [6, 7, 8, 9, 10, 11, 13, 15, 17, 18], meaning the cow died on lane 6

1. if your hashed server seed wasn't shown before playing

2. if your hashed server seed was shown to you only after committing to a client seed

3. if the algorithm was changed to use a different part of the hash (you can verify that this isn't the case with steps above)

4. if your hashed server seed didn't match the unhashed seed when checking with a SHA-256 tool

• beef provably fair works by combining your client seed, server seed, nonce and cursor to shuffle numbers corresponding to death positions in a random and unpredictable way

• death positions are predetermined, your cow being run over is purely visual
• "Fisher-Yates" shuffling method is used for the final death positions - meaning that for each round, the 0-19 sequence is shuffled 19 times, and the resulting sequence of numbers dictates where your cow dies

• since you're able to set a client seed (after the hashed server seed is revealed), there's nothing Duel can do to skew the odds without players immediately noticing.