using System;

using System.Text;

using System.Security.Cryptography;     

​

public class Program

{

    public static void Main()

    {

        string userProvidedSecret = "";

        string raw = string.IsNullOrEmpty(userProvidedSecret) ? GenerateSecret() : userProvidedSecret;

        Console.WriteLine($"Secret Value {raw}, hashed {HashString(raw)}");

    }

    public static string HashString(string s) {

        using(var sha = SHA256.Create()) {

            byte[] hashed = sha.ComputeHash(Encoding.UTF8.GetBytes(s));

            return Convert.ToBase64String(hashed);

        }

    }

    public static string GenerateSecret() {

        using(RandomNumberGenerator rng = new RNGCryptoServiceProvider()) {

            byte[] tokenData = new byte[32];

            rng.GetBytes(tokenData);

            return Convert.ToBase64String(tokenData);

        }   

    }

}