解密操作如下:

 private void UnProtectSection(string sectionName)
    {
        Configuration config =
            WebConfigurationManager.
                OpenWebConfiguration(Request.ApplicationPath);
        ConfigurationSection section = config.GetSection(sectionName);
        if (section != null && section.SectionInformation.IsProtected)
        {
            section.SectionInformation.UnprotectSection();
            config.Save();
        }
    }