using System;

using System.Text;

using System.Linq;

using System.Collections.Generic;

using System.Security.Cryptography;

​

public class Program

{

    public static void Main()

    {

        var input = "Hello";

        var hash = CreateHash(input);

​

        Console.WriteLine($"Key: {hash.Key.Length} bytes");

        DumpArray(hash.Key);

        Console.WriteLine();

        Console.WriteLine($"Data: {hash.Data.Length} bytes");

        DumpArray(hash.Data);

        Console.WriteLine();

​

        Console.WriteLine("-----------------------------------------------------");

        Console.WriteLine();

​

        var areEqual = VerifyHash(input, hash.Key, hash.Data);

        Console.WriteLine($"Are equivalent: {areEqual}");

    }

    static (byte[] Key, byte[] Data) CreateHash(string input)

    {

        using var alg = new HMACSHA512();

        return (alg.Key, alg.ComputeHash(Encoding.UTF8.GetBytes(input)));

    }

    static bool VerifyHash(string input, byte[] key, byte[] data)

    {

        using var alg = new HMACSHA512(key);

        var computedData = alg.ComputeHash(Encoding.UTF8.GetBytes(input));

        DumpArray(computedData);

        return new HashSet<byte>(computedData).SetEquals(data);

    }

    static void DumpArray(byte[] bytes, int bytesPerLine = 16)

    {

        StringBuilder sb = new StringBuilder();

        for (int line = 0; line < bytes.Length; line += bytesPerLine)

        {

            var lineBytes = bytes.Skip(line).Take(bytesPerLine).ToArray();

            sb.AppendFormat("{0:x8}: ", line);

            sb.Append(string.Join(" ", lineBytes.Select(b => b.ToString("X2")).ToArray()).PadRight(bytesPerLine * 3));

            sb.Append("| ");

            sb.AppendLine(new string(lineBytes.Select(b => b < 32 ? '.' : (char)b).ToArray()));

        }

        Console.Write(sb.ToString());

    }   

}