Decrypting ConnectionString
try
{
    Configuration config = WebConfigurationManager.OpenWebConfiguration("~");
    ConfigurationSection section = config.GetSection("connectionStrings");
    if (!section.SectionInformation.IsProtected)
    {
       section.SectionInformation.ProtectSection("RSAProtectedConfigurationProvider");
       config.Save();
    }
    catch (Exception ex)
    {

    }

Configuration config = WebConfigurationManager.OpenWebConfiguration(Request.ApplicationPath);
ConfigurationSection section = config.GetSection("connectionStrings");
if (section.SectionInformation.IsProtected)
{
    section.SectionInformation.UnprotectSection();
    config.Save();
}