Example of generation of a random seed from the revealed nonces in the Tezos blockchain

TezosRandomSeed.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Isopoh.Cryptography.Blake2b;
using Newtonsoft.Json.Linq;
using Netezos.Rpc;

namespace TezosRandomSeed
{
    public static class TezosRandomSeed
    {
        public static async Task Test()
        {
            using (var rpc = new TezosRpc("https://mainnet.tezrpc.me"))
            {
                var nonces98 = await rpc
                                .Blocks[409599]
                                .Context
                                .Raw
                                .Cycles[98]
                                .Nonces
                                .GetAsync(1);

                var seed104 = (await rpc
                                .Blocks[430081]
                                .Context
                                .Raw
                                .Cycles[104]
                                .RandomSeed
                                .GetAsync())
                                .Value<string>();

                var seed105 = GetRandomSeed(
                                seed104, 
                                nonces98
                                    .Where(x => x[1] is JValue)
                                    .Select(x => x[1].Value<string>()));

                //"3a7c01910c7ad92bb7712733822c35c893077c105e0d05cdfa312eea2bfd3412"
            }
        }
        
        public static void Test2()
        {
            var seed0 = B2B("");
            var seed1 = GetRandomSeed(seed0, Enumerable.Empty<string>());
            var seed2 = GetRandomSeed(seed1, Enumerable.Empty<string>());
        }

        public static string GetRandomSeed(string prevSeed, IEnumerable<string> nonces)
        {
            var seed = B2B(prevSeed + "0000000000000000000000000000000000000000000000000000000000000000");
            foreach (var nonce in nonces) seed = B2B(seed + nonce);
            return seed;
        }

        static string B2B(string data)
        {
            var bytes = Blake2B.ComputeHash(
                            Enumerable.Range(0, data.Length)
                                      .Where(x => x % 2 == 0)
                                      .Select(x => Convert.ToByte(data.Substring(x, 2), 16))
                                      .ToArray(),
                            new Blake2BConfig { OutputSizeInBytes = 32 },
                            null);

            return BitConverter.ToString(bytes).Replace("-", "").ToLower();
        }
    }
}