Securing Configuration Files in ASP.NET

using System;
using System.Configuration;

namespace ConfigEncryption
{
    public class ConfigUtility
    {
        /// <summary>
        /// Encrypt the config file an save it
        /// </summary>
        public static void ConfigEncryptToFile()
        {
            string encrypted = ConfigurationManager.AppSettings.Get("Encrypted");

            if (encrypted == null || !encrypted.Equals("True"))
            {
                string keysToEncrypt = ConfigurationManager.AppSettings.Get("KeysToEncrypt");

                if (keysToEncrypt != null && keysToEncrypt.Length > 0)
                {
                    Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
                    AppSettingsSection appSettings = config.AppSettings;

                    string[] keys = keysToEncrypt.Split(',');

                    foreach (string key in keys)
                    {
                        KeyValueConfigurationElement kv = appSettings.Settings[key];
                        if (kv != null)
                        {
                            kv.Value = EncryptUtility.EncryptString(EncryptUtility.ToSecureString(kv.Value));
                        }
                    }

                    appSettings.Settings.Add("Encrypted", "True");
                    config.Save(ConfigurationSaveMode.Modified);
                }  
            }
        }

        /// <summary>
        /// Decrypt configuration settings into memory
        /// </summary>
        public static void ConfigDecryptToMemory()
        {
            ConfigurationManager.RefreshSection("appSettings");

            string encrypted = ConfigurationManager.AppSettings.Get("Encrypted");

            if (encrypted != null && encrypted.Equals("True"))
            {
                string keysToDecrypt = ConfigurationManager.AppSettings.Get("KeysToEncrypt");

                string[] keys = keysToDecrypt.Split(',');

                foreach (string key in keys)
                {
                    string value = ConfigurationManager.AppSettings.Get(key);
                    value = EncryptUtility.ToInsecureString(EncryptUtility.DecryptString(value));
                    ConfigurationManager.AppSettings.Set(key, value);
                }
            }
        }

    }
}