Incidentally, you're looking at it as you would having to go through the entire matrix to do so, which is the basis of occasionally needing Data Search+Browse to find the node which is the equivalent of tracking down the ip address over the incredibly poorly-secured internet of SR4 (hence the crackdown between SR4 and SR5 which only really kicked out the program rating system and introduced GOD as an actual meaningful entity). For Mutual Signal Range (MSR)... Consider how Bluetooth technology works currently. MSR seems to be taken from a similar concept to that. The whole idea appears to have been that nothing non-technomancer is meant to be unhackable unless it's encrypted, the benefit being that hackers won't sit around bored because they couldn't get a hit on their perception (poor luck) or they were silly and didn't get Analyze (and are thus very silly).
Just a bit of (hopefully) helpful info. Not arguing rules, because otherwise I'm pretty sure I've been handling Encryption wrong the entire time for the sake of brevity. (I think you're supposed to Decrypt, THEN Analyze as Encryption prevents you doing anything to the node, but that takes a bit long in PBP as then it'd have to be Decrypt, response, Analyze, response, possibly remove data bombs, response, then actually begin hacking. And when you consider that encryptions can have data bombs in them...).