Program.cs

// ReSharper disable All
using System;
using NBitcoin;

namespace HdWallet
{
    internal class Program
    {
        private static void Main()
        {
            ExtKey masterKey = new ExtKey();
            Console.WriteLine("Master key : " + masterKey.ToString(Network.Main));
            for (int i = 0; i < 5; i++)
            {
                ExtKey key = masterKey.Derive((uint) i);
                Console.WriteLine("Key " + i + " : " + key.ToString(Network.Main));
            }

            ExtPubKey masterPubKey = masterKey.Neuter();
            for (int i = 0; i < 5; i++)
            {
                ExtPubKey pubkey = masterPubKey.Derive((uint) i);
                Console.WriteLine("PubKey " + i + " : " + pubkey.ToString(Network.Main));
            }

            masterKey = new ExtKey();
            masterPubKey = masterKey.Neuter();

            //The payment server generate pubkey1
            ExtPubKey pubkey1 = masterPubKey.Derive((uint) 1);

            //You get the private key of pubkey1
            ExtKey key1 = masterKey.Derive((uint) 1);

            //Check it is legit
            Console.WriteLine("Generated address : " + pubkey1.PubKey.GetAddress(Network.Main));
            Console.WriteLine("Expected address : " + key1.PrivateKey.PubKey.GetAddress(Network.Main));

            ExtKey parent = new ExtKey();
            ExtKey child11 = parent.Derive(1).Derive(1);

            // OR
            parent = new ExtKey();
            child11 = parent.Derive(new KeyPath("1/1"));

            ExtKey ceoKey = new ExtKey();
            Console.WriteLine("CEO: " + ceoKey.ToString(Network.Main));
            ExtKey accountingKey = ceoKey.Derive(0, hardened: true);

            ExtPubKey ceoPubkey = ceoKey.Neuter();

            //ExtKey ceoKeyRecovered = accountingKey.GetParentExtKey(ceoPubkey); //Crash

            var nonHardened = new KeyPath("1/2/3");
            var hardened = new KeyPath("1/2/3'");

            ceoKey = new ExtKey();
            string accounting = "1'";
            int customerId = 5;
            int paymentId = 50;
            KeyPath path = new KeyPath(accounting + "/" + customerId + "/" + paymentId);
            //Path : "1'/5/50"
            ExtKey paymentKey = ceoKey.Derive(path);

            Mnemonic mnemo = new Mnemonic(Wordlist.English, WordCount.Twelve);
            ExtKey hdRoot = mnemo.DeriveExtKey("my password");
            Console.WriteLine(mnemo);

            mnemo = new Mnemonic("minute put grant neglect anxiety case globe win famous correct turn link",
                Wordlist.English);
            hdRoot = mnemo.DeriveExtKey("my password");

            Console.ReadLine();
        }
    }
}