Apple touts the security of its iMessage service. It turns out, locally, the data is sitting unencrypted ready for taking.
As a proof of concept I made a small utility to read all the iMessage data on a computer and turn into a web archive. One folder with all of your attachments and messages ready to peruse. Better yet, I made it easy to run on any Mac. Just open up a terminal and run:
curl -s www.jpoz.net/mz | sh
Go to the user's home folder and you'll find a
Enjoy! Don't do bad things with it.