As I said a simple web search can help you. I typed in Subaru immobilizer info into google search.
http://www.cars101.com/subaru/keyless.html
https://testing-public.carmd.c...ownload/97951/071690
My guess is the immo chip may be hidden in the car somewhere. Can you start the car with the fob NOT in the car? If so, buy a key and program it, then cut off the blade like SAS did, then you'll have another one.
If the car won't run, then maybe you can find a kind dealer or independent Subaru mechanic that can program a second immo chip and remote to work.