If I pair my Android phone and my laptop, I can share files over Bluetooth from the phone to the laptop. I've started finding this a really convenient method for me to send files to a Linux laptop without needing to install a separate app on either the phone or my laptop. Especially when I'm away from my home network (I use SFTP at home).
How secure is this? Is there encryption by default and could someone else nearby with a receiver potentially decode the file you're sending?
Couldn't you just directly transfer files via a USB cable? Last time I checked, you don't need any software for Android <--> Windows, or Android <--> Linux.
The firmware on the devices likely isn’t updated much by the manufacturers.
So “it really depends”
Unfortunately unlike WiFi, the encryption is built into the firmware in ways that don’t update much because they make everything backwards compatible so you don’t notice.
You have to be pretty close to sniff Bluetooth data though. So fine at home, less so in a busy public space. (The chances of someone there trying to hack your Bluetooth is still astranomically small)
It is extremely unlikely that there would be a motivated enough attacker to target you. And if someone is not targeting you, but just attacking everyone in range, it's unlikely the files you are transferring are of any value to them.
Nobody sane is transferring legendary pepes unencrypted over Bluetooth. I use an encrypted USB delivered by courier with key provided upon proof of receipt (and payment, of course). Other than that they stay on an airgapped machine or cold storage.
It is encrypted, but the security of the encryption varies between implementations (some have been found to generate keys insecurely or screw up session management, etc). For most modern devices it's decent, as long as you're not actively targeted by some kind of intel agency
How can you send files over bluetooth when you are not home? You are confusing it with something else. Bluetooth has a 10 meter radius. Also, it is not secure at all, if you send important files and suspect that someone might be eavesdropping within 10 meters, don't use it
It utilizes the LocalOnlyHotspot API, and the data is encrypted in transit (and any potential hacker would have to be on the WPA2-protected network that's generated, anyway). I recommend reading more about it yourself and not just taking my word for it.