Encrypt connectionstring in web.config

You can encrypt it from the DOS prompt, if you have access to it..
c:\windows\microsoft.net\framework\Vx\aspnet_regiis.exe -pef "connectionStrings" c:\Inetpub\foldername

The key to decrypt it lies on the same machine where it was encrypted.
When your application access the connectionstrings it would automatically do the decryption.