abt how to use session..

Session.Add("SessionName","YourValue");
// That's how u add value to session...

string username = Session["YouValue"].toString();
// Grab the value from session..
Next SHA Encryption.. try this SHA512 code and go to heaven

Code:
protected string MySHA512( )

    {

        SHA512 sha512 = new System.Security.Cryptography.SHA512Managed();

        byte[] sha512Bytes = System.Text.Encoding.Default.GetBytes("vb.netdev");

        byte[] cryString = sha512.ComputeHash(sha512Bytes);

        string sha512Str = string.Empty;

        for (int i = 0; i < cryString.Length; i++)

        {

            sha512Str += cryString[i].ToString("X");

        }

        return sha512Str;

    }
hope that helps.