While i want to try to impliment in my project it giveing error

using System;
using System.Data;
using System.Configuration;
using System.Web.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

/// <summary>
/// Summary description for clsEncrypt
/// </summary>
public class clsEncrypt
{
    //public clsEncrypt()
    //{
        //
        // TODO: Add constructor logic here
        //
    //}
   public static object webencrypt()
{
	Configuration config = WebConfigurationManager.OpenWebConfiguration("~");
	//' Write the section name of web.config file (connectionStrings)
    ConfigurationSection configSection = config.GetSection("connectionStrings"); ;
	

	//' Check the section  of web.config file (connectionStrings) if Protected 
	//' then UnprotectSection (decrypt) the section
	if (configSection.SectionInformation.IsProtected) 
    {
		configSection.SectionInformation.UnprotectSection();
		config.Save();
	} 
    else
    {
		//' Check the section of web.config file (connectionStrings) 
		//' if UnprotectSection then 
		//' protect (encrypt) Section the section
        configSection.SectionInformation.ProtectSection("DataProtectionConfigurationProvider");
		config.Save();
	}
    return config;
}

    
}