Strategy to distribute secure database connection strings in an enterprise environment

// Copyright � 2003
// Author : Sriram Chitturi
// Date : November 29, 2003

using System;
using Microsoft.Win32;
using System.Configuration;

namespace EnterpriseConnString
{
	// Singleton class to get the keyword
	// from either Registry or config file

	// Customize this class to read KeyWord from any source
	public class Keyword
	{
		private static string m_keyword = null;

		private Keyword()
		{
		}
		public static string GetKeyWord()
		{
			// use any of the methods below to retrieve a keyword, depends on
			// enterprise level security

			if (m_keyword == null)
			{
				// m_keyword = ReadFromRegistry();
				m_keyword = ReadFromConfigFile();
			}
			if (m_keyword.Length != 8)
			{
				m_keyword = null;
				throw new Exception("Keyword should be 8 characters since DES encryption is being used");
			}

			return m_keyword;
		}

		private static string ReadFromRegistry()
		{
			// keyword should be already present in the registry
			// If you want to create keyword in registry
			// use a reg file with the following 3 lines

			// Windows Registry Editor Version 5.00
			// [HKEY_LOCAL_MACHINE\SOFTWARE\ECS]
			// "keyword"="MyKeyWord"

			RegistryKey HKLM = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\ECS");
			string regvalue = (string)HKLM.GetValue("KeyWord");
			if (regvalue == null)
				throw new Exception("KeyWord not found in Registry!");
			return regvalue;
		}

		private static string ReadFromConfigFile()
		{
			// use a config file to set the keyword
			// administrators can use machine.config files to set enterprise wide
			// keywords. This can enable administrators to change keywords often.
			// Note : Whenever the keyword is changed, run admin console to
			//			update the server Registry

			// I am using a local app.config file to set the keyword as an example
			string [] values = ConfigurationSettings.AppSettings.GetValues("keyword");
			if (values == null)
				throw new Exception("Keyword not found in config file!");
			return (string)(values[0]);
		}
	
	}
}