First of all, if you password encrypt the xml file, and that file is replaced, it probably is not encrypted anymore, or another key is used. That would result in an error, which should be enough to send out a warning to the user.
As an alternative, you can use an MD5 hash. You use the original XML file to create the hash, and when you read the file the hash should be the same. I don't think that this is any safer or better than your solution. Yeah someone could decompile the movie, replace the hash, but how many of your users will have the knowledge and time to do something like this?
Thanks for the quick reply - your point on the password protection is useful. Can you point me to a tutorial on the
implementation of the MD5 hash method - I am fairly new to xml
I haven't used this myself, but this is what I've found:
Using this you probably don't need to encrypt the file. But if that works, if it ain't that resource intensive, why bother? Stick with what you have if it works.