using System;

using System.Globalization;

using System.Linq;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff"));

        var secretHash = GetInput(">请输入秘密哈希：");

        var secretSalt = GetInput(">请输入秘密盐：");

        var publicHash = GetInput(">请输入公开哈希：");

        var clientSeed = GetInput(">请输入用户种子：");

​

        if (publicHash == HashUtil.GeneratePublishHash(secretHash, secretSalt))

            Console.WriteLine("公开哈希有效");

        else

        {

            Console.WriteLine("公开哈希无效");

            return;

        }

​

        while (true)

        {

            var roundInString = GetInput("请输入回合数：");

            if (!int.TryParse(roundInString, out int round))

                continue;

​

            var rollNumber = HashUtil.ComputeRollNumber(secretHash, clientSeed, round);

            Console.WriteLine($"回合数为 {round} 时的Roll点为 {rollNumber}");

        }

    }

​

    private static string GetInput(string prompt)

    {

        string line = null;

        while (string.IsNullOrWhiteSpace(line)) {

            Console.Write(prompt);      

            line = Console.ReadLine();

        }

        return line;

    }

    public static class HashUtil

    {

        public const long ROLL_SEED_MIN = 0L;

        public const long ROLL_SEED_MAX = 1_000_000L;

​

        public static string GeneratePublishHash(string secretHash, string secretSalt)

        {

            var bytes = Unhexlify(secretHash + secretSalt);

            using var hash = SHA256.Create();

            var hashBytes = hash.ComputeHash(bytes);

            return HexDigest(hashBytes);

        }

​

        public static int ComputeRollNumber(string secretHash, string clientSeed, int round)

        {

            var secret = Unhexlify(secretHash);

            var seed = $"{clientSeed}-{round}";

            using HMACSHA512 hmac = new HMACSHA512(secret);

            var hashBytes = hmac.ComputeHash(Encoding.UTF8.GetBytes(seed));

            var hash = HexDigest(hashBytes);

            var subHash = hash.Substring(0,7);

            var number = long.Parse(subHash, NumberStyles.HexNumber);

            return (int)(number % ROLL_SEED_MAX + ROLL_SEED_MIN);

        }

​

        private static byte[] Unhexlify(string text)

        {

            if ((text.Length % 2) != 0)

                throw new ArgumentException("Invalid length: " + text.Length);

​

            if (text.StartsWith("0x", StringComparison.InvariantCultureIgnoreCase))

                text = text.Substring(2);

​

            int arrayLength = text.Length / 2;

            byte[] byteArray = new byte[arrayLength];

            for (int i = 0; i < arrayLength; i++)

            {

                byteArray[i] = byte.Parse(text.Substring(i * 2, 2), NumberStyles.HexNumber);

            }

​

            return byteArray;

        }

​

        private static string HexDigest(byte[] bytes) => BitConverter.ToString(bytes).Replace("-", "").ToLower();

    }

}

​

​