Originally Posted by Panda Rose
Thanks for that. I have done it through ADE. To me, the old fashioned way!
Open the .acsm file with a text editor - even Notepad. You'll see that it's little more than a URL and long hex key(s). That file merely tells ADE part of the encrypted handshake with an Adobe Content Server to receive back an encrypted ebook - encrypted for your specific device(s).
Calibre doesn't now (and I hope never does) support DRM, so you're not going to get much out of an .acsm file anytime soon....