Cómo hacer un hash SHA512 en C#

using System;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
 
/* Necesario para hash SHA512 */
using System.Security.Cryptography;
using System.Text;
 
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
 
        string text = "Texto a hashear";
        string hashkey = "*hg849gh84th==3tg7-534d=_";
        string hash = CreateSHAHash(text, hashkey);
 
        Label1.Text = text + " -- su hash es: " + hash.ToString() + "<br />Longitud: " + hash.Length.ToString();
    }
 
 
    /// <summary>
    /// Creación de Hash SHA512
    /// </summary>
    /// <param name="Text">Texto a realizar hash</param>
    /// <param name="Salt">Palabra de Seguridad a concatenar a texto a realizar Hash</param>
    /// <returns>String con Hash SHA512 aplicado</returns>
    public static string CreateSHAHash(string Text, string Salt)
    {
        System.Security.Cryptography.SHA512Managed HashTool = new System.Security.Cryptography.SHA512Managed();
        Byte[] HashAsByte = System.Text.Encoding.UTF8.GetBytes(string.Concat(Text, Salt));
        Byte[] EncryptedBytes = HashTool.ComputeHash(HashAsByte);
        HashTool.Clear();
        return Convert.ToBase64String(EncryptedBytes);
    }
 
}