The government agency I work with sends me files encrypted with epm. I have the passwords. Is there a way to decrypt these files using Linux?
I had never heard of EPM before. After ten minutes scrobbling around the internet, I'm fairly confident you're talking about a disk/volume encryption format from Check Point Software:
On the specifications tab it doesn't include Linux as a supported operating system and because this is a proprietary media encryption format, I feel it's unlikely that there are any open source tools to decrypt the volume.
That leaves you with a few options, none ideal:
Ask the agency to send you the data you need in another format. Some agencies encrypt everything regardless of need. If this is non-sensitive data argue that it doesn't need encrypting. If they can use alternative software (like a Truecrypted USB drive) that would also work for you. You never know, they might even listen.
Ask Check Point Software for a Linux version. Unless they're already working on it, don't hold your breath. This is serious software that will require serious (long and expensive) testing.
Install Windows in VirtualBox, install Check Point and try to copy the data out. From what I can see, Check Point is going to try to stop this. And it's probably going to win.
Give up. Use Windows-proper.