It's hard to put it into words but I think, to me, Star Wars is highly advanced analog technology vs Star Trek's highly advanced digital technology.
As far as encryption goes, yes they have it but I don't think it's anything like we have now. Now we have commercial grade encryption that unless you have the key it takes massive amounts of computer power years to crack. I see star wars encryption more like a simpler basic encryption that would be easy to beat today in our digital world, but would be cutting edge for an advanced analog world.
The challenge there, as noted above, is that at least in our world, we know from experience that takes far less computing power to create and use very hard encryption, than it does to create artificial intelligence. So, unless there's something very different in the Star Wars world... they have droids with very deep AI, so they have the computer technology for very fast very complex encryption.
"In our world" is the key difference there though. We live in a digital world and in a digital world encryption is easy to use because didgital systems excell at the types of calculations that encryption requires.
I'm a fan of the fallout games and I see a lot of similarities between the robots of star wars and the robots there. They're analog, complete with vacuum tubes and everything. There's no saying what an analog robot would be able to do with encryption. Digital systems are all yes/no, 1/0, on/off. Analog are yes, no, maybe, and I don't know. A digital AI requires massive amounts of processing power because it can't just work. It has to work through every yes/no possibility. An analog or star wars droid doesn't have to use probability calculations and massive amounts of processing to figure out what to do. It can use that maybe, and I don't know. So while a Star Wars robot can be a sentient entity, much like a living creature, there's no evidence that it has the massive amounts of processing power like you see in Star Trek's Data or a modern super computer.
If a player can wrap their heads around things not being digital then it gets a lot easier to understand Star Wars technology. Granted this is easier to do for those of us who didn't grow up surrounded by everything digital.
And in a world where encryption isn't easy, then it makes complete sense not to do things wirelesly because of all of the droids out there like you said.