如何将PrimeDice可证明公平的百分骰脚本改为六面骰？

Got it, let's tweak that PrimeDice provably fair script to roll a standard 6-sided die instead of a 100-sided one. Here's how to do it step by step:

Step 1: Context for the Original Roll Function #

First, let's fill in the missing portion of the official roll function (your snippet cut off mid-logic). The original code extracts a numeric value from the SHA512 hash and scales it to a 0-99 range for the 100-sided roll. Here's the complete standard implementation for reference:

var crypto = require('crypto');
var roll = function(key, text) {
    var hash = crypto.createHmac('sha512', key).update(text).digest('hex');
    var index = 0;
    var result;
    do {
        result = parseInt(hash.substring(index * 5, index * 5 + 5), 16);
        index++;
    } while (result >= 100000); // Restrict to values that fit 0-99
    return result % 100; // Returns 0-99 for 100-sided roll
};

Step 2: Modified Code for 6-Sided Die (1-6) #

The core changes are adjusting the range check to avoid bias and updating the final calculation to map to a 1-6 range. Here's the fully updated script:

var clientSeed = "Test1";
var serverSeed = "a72c7d6e95badadadab91d729f4eef30af2c019488bb76274290ad183";
var nonce = 1;

var crypto = require('crypto');
var rollD6 = function(key, text) {
    var hash = crypto.createHmac('sha512', key).update(text).digest('hex');
    var index = 0;
    var result;
    // Use the largest multiple of 6 less than 16^5 (1048576) to avoid bias
    // 1048572 = 6 * 174762, so all values below this divide evenly into 6 outcomes
    do {
        result = parseInt(hash.substring(index * 5, index * 5 + 5), 16);
        index++;
    } while (result >= 1048572);
    // Convert 0-5 modulo result to standard 1-6 die range
    return (result % 6) + 1;
};

// Calculate and log your 6-sided roll
var d6Result = rollD6(serverSeed, clientSeed + '-' + nonce);
console.log('Your 6-sided die roll:', d6Result);

Key Changes Breakdown #

• Bias-Free Range Check: Instead of limiting values to <100000, we use a range divisible by 6. This ensures every die face (1-6) has an equal probability of being rolled.
• Final Roll Calculation: (result % 6) + 1 shifts the 0-5 modulo result to the standard 1-6 die range that players expect.
• Provable Fairness Preservation: We keep the original input structure (clientSeed + '-' + nonce) to maintain PrimeDice's provably fair verification flow.

Quick Verification Tip #

To keep the system provably fair:

• Keep the server seed secret until all rolls using that seed are completed (per PrimeDice's standard practice)
• Increment the nonce by 1 for every subsequent roll with the same client/server seed pair

内容的提问来源于stack exchange，提问作者user9586797