BOS Terminals C and E are connected air-side, so you'll be able to walk from your arrival gate to the departure gate without having to pass through a security checkpoint. A 1h07m connection time is still very risky, though. If your domestic flight is even 30 minutes late to arrive you may miss the cutoff time for your international departure. (You need to allow at least 5 minutes from "arrival" to when the door opens at the gate, plus time to exit the plane, plus time to walk from gate to gate, plus the 10-15 minute cutoff before departure.) As others have noted, because you are traveling on two separate tickets neither airline will take responsibility if you miss the connecting flight. You'll be on your own to buy a new ticket and pay for other costs such as hotel and meals. Bottom line, if it were my trip I would not accept this itinerary. Too risky.