In this Post Decrypt Password for User Authentication in Asp.Net

Important Namespaces Used
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using System.Data;
using System.Data.SqlClient;
using System.Text;


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Variable Used
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static String decryptedpwd;

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Login Button Click Event
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 String mycon = "Data Source=HP-PC\\SQLEXPRESS;Initial Catalog=UserLoginData;Integrated Security=True";
        SqlConnection scon = new SqlConnection(mycon);
        String myquery = "select * from userlogin where username='" + TextBox1.Text + "'";
        SqlCommand cmd = new SqlCommand();
        cmd.CommandText = myquery;
        cmd.Connection = scon;
        SqlDataAdapter da = new SqlDataAdapter();
        da.SelectCommand = cmd;
        DataSet ds = new DataSet();
        da.Fill(ds);
        String uname;
        String pass;
       
        if (ds.Tables[0].Rows.Count > 0)
        {
            uname = ds.Tables[0].Rows[0]["username"].ToString();
            pass = ds.Tables[0].Rows[0]["password"].ToString();
            
            scon.Close();
            decryptpwd(pass);
            if (uname == TextBox1.Text && decryptedpwd == TextBox2.Text)
            {
                Session["username"] = uname;
                Response.Redirect("Success.aspx");
            }
            else
            {
                Label3.Text = "Invalid Login Details. Try to enter Username/password Carefully";
            }

        }
        else
        {
            Label3.Text = "Invalid Login Details. Try to enter Username/password Carefully";
        }

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User Defined Method
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private void decryptpwd(String encrytpwd)
    {
        string decryptpwd = string.Empty;
        UTF8Encoding encodepwd = new UTF8Encoding();
        Decoder Decode = encodepwd.GetDecoder();
        byte[] todecode_byte = Convert.FromBase64String(encrytpwd);
        int charCount = Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length);
        char[] decoded_char = new char[charCount];
        Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);
        decryptpwd = new String(decoded_char);
        decryptedpwd = decryptpwd;
        
    }

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Success.aspx Page Coding
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Page Load Coding
===========

 Label2.Text = "Hello " + Session["username"] + " , Welcome to Our Website";

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Logout button click event
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Session.Abandon();
        Label2.Text = "You have successfully Logout";
        Button1.Visible = false;

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