SHA Tester 2.0, C#

Language: Layout:

//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Text;
using System.Security.Cryptography;
using System.Globalization;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //Your code goes here
            Console.WriteLine("Client sends: " + Sha256StringHash("marcor"));

Console.WriteLine("Server stores: " + Sha256StringHash(Sha256StringHash("marcor"), GetSalt(Guid.Parse("9585ac17-4b86-4b1e-963c-4100c736b432"), DateTime.Parse("2017-01-11 17:35:20"))));
        }
        
        public static string Sha256StringHash(string input)
        {
            using (var shaM = new SHA256Managed())
            {
                var hash = shaM.ComputeHash(Encoding.UTF8.GetBytes(input));

return HashToString(hash);
            }
        }

public static string Sha256StringHash(string input, string salt)
        {
            using (var shaM = new SHA256Managed())
            {
                var bytesInput = Encoding.UTF8.GetBytes(input);
                var bytesSalt = Encoding.UTF8.GetBytes(salt);

var data = new byte[bytesInput.Length + bytesSalt.Length];

bytesInput.CopyTo(data, 0);
                bytesSalt.CopyTo(data, bytesInput.Length);

var hash = shaM.ComputeHash(Encoding.UTF8.GetBytes(input));

return HashToString(hash);
            }
        }

public static string GetSalt(Guid id, DateTime createdAt)
        {
            var toHash = createdAt.Day % 2 == 0 ? id.ToString() + createdAt : createdAt.ToString(CultureInfo.InvariantCulture) + id;

using (var shaM = new SHA256Managed())
            {
                var hash = shaM.ComputeHash(Encoding.UTF8.GetBytes(toHash));

return HashToString(hash).Substring(0, 5);
            }
        }

private static string HashToString(byte[] hash)
        {
            var sBuilder = new StringBuilder();

foreach (var b in hash)
                sBuilder.Append(b.ToString("x2"));

return sBuilder.ToString();
        }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0,16 sec, absolute running time: 0,09 sec, cpu time: 0,08 sec, average memory usage: 14 Mb, average nr of threads: 3