1. how would you recommend that I make sure that the signal is only in my own house?
2. If I put a choke on the electrical main, would that stop or distort the signal so it stays a closed circuit?
3. If not, is there any way I can encrypt the signal using AES or the like?
4. I'd rather not have someone hacking my house and unlocking my doors by using the backdoor on the flawed protocol.
1. You can't. Even the whole house filter, PZZ01, from X10 Pro,only attenuates incoming or outgoing PLC signal by about 30:1.
2. A 200 amp choke? Also if it distorts any incoming signal it will also distort the internal signal.
3. No.
4. X10 is not impervalous to faulsing. A power outage followed by a "brown-up" type of power restoration can cause modules to turn on. Although some people do use the X10 Universal Module to control electric striker plates it is not especially secure. X10 protocol was developed in the very late 1970's, long before any type of encryption.
Since you are a technician read this:
http://hometoys.com/emagazine.php?url=/htinews/feb99/articles/kingery/kingery13.htm.
Based on your concerns seen in two different threads, I don't think X10 is a good choice. Check out Z-Wave. As far as your range questions, search this forum using "range", "RF range", "wireless range", etc.