Black Market fairness

Black Market uses a Provably Fair system to determine the offers generated during each game. The selected slot for each offer is determined by the server seed, client seed, nonce, a unique offer salt, and the weighted slot configuration for that offer.
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Each game uses a single base nonce. To distinguish offers within the same game, each offer uses a unique salt in the format black-market:offer:<offerNumber>. This allows every offer to be calculated independently while remaining tied to the same game seed information.
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For each offer, the salt, server seed, client seed, and nonce are combined into a single seed value. This combined seed is used with HMAC-SHA256 to generate a deterministic roll value. The roll value is then checked against the cumulative weights of the configured slots to determine which slot, and therefore which multiplier, was selected.
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As the game progresses, the selected multipliers are applied cumulatively. The offer multiplier is calculated from the cumulative multiplier after applying the configured house edge. When a bet amount is provided, the resulting offer value can also be calculated. The cumulative multiplier and offer multiplier are calculated to eight decimal places, and the offer value is rounded down to eight decimal places.
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​Independent Verification
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You can independently verify any previous Black Market game here:
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​Click here for Independent Verification Script
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Simply input the server seed, client seed, nonce, house edge percentage, and slot configurations from the game you want to verify. To also verify the displayed offer values, input the bet amount.
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You can execute this code yourself using Node.js, but we understand that for some of you, this may be beyond your technical know-how. So, we have created an easy way for you to execute this code directly from your browser. It runs the same verification code without the hassle of having to set up Node.js on your home computer.
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With this system, each offer's roll value, selected multiplier, cumulative multiplier, offer multiplier, and optional offer value can be independently reproduced and checked.