I am developing an app that controls a product's operation. The communication is via BLE. My configuration is
App - Peripheral (iOS, Android)
Product - Central (uses Laird BT900 module)
iOS as a peripheral works fine (pairing and bonding) ; Android PIN pairing works fine, but subsequent bonding (or reconnect when in range) there are a lot of issues and termination of connection. I am using the supported list of devices for Android BLE and I also understand that there are many known issues that come with different manufacturers/chipset vendors
The issue I am getting is, as seen by nrfConnect, is with descriptors. Android app doesnt show descriptors when seen in nrfConnect whereas iOS shows. I do not know what is the difference
Is it a common practice to use a phone as a peripheral ? Or is it a risk - because this is a medical device.
Are there any best practices for Android as a peripheral ?
I have following back up plans in case Android issue is not resolved. I think following would work on any BLE supported phones without having any issues with the variability.
Plan A : PIN pairing on every connection with the product. This is the most secure and most annoying
Plan B : Implement just works pairing with a app layer password before taking control of the product.
Question : Is just works safe and encrypted ? Is it snoop-safe or MITM-safe ?
Thanks in advance!
A few thoughts from your questions:
1a. (From my Android experience) I think its uncommon to have the phone be the peripheral. To my knowledge all iOS devices support peripheral mode but only a very small subset of Android devices are able to support it. I say this because I've been experimenting with BTLE beacons using the AltBeacon library. From this work I have discovered that only certain Android phones can broadcast BTLE advertise packets. Given that BTLE advertising is the first step in initiating a BTLE session I imagine that this prevents many Android phones from being compatible with peripheral mode.
If all of your users can use an iOS device, then you're set, otherwise this may be a problem.
1b) I can't speak to the specific risk of using a mobile device with your medical device, that depends on what the medical device is doing and how you're using the mobile app.
2) See 1a
3) The specific encryption scheme you used is also based on your product's risk profile. I would say that Just Works is not an ideal solution. The just works pairing process is not snoop-safe and can be re-initiated via a MITM. Other than that I can't speak to the strength of BTLE encryption.
Related
When connection to a custom BLE device from an app (android and ios) I have two options
a) first pair the device on the phone (like a headset or other devices) and then use it from the app to read and write data
b) without pairing on the phone, go inside the app, search for a device with a specific name or address, and just connect to it and read and write data.
when is one preferred over the other one ?
Its just when it needs to interact in the background or am I missing something?
The devices you see in your phones Bluetooth settings are Bluetooth Classic devices. There are some devices using both BLE and Bluetooth Classic which show up in the settings too, but the settings page is only for the Bluetooth Classic part of the device. Headphones for example are streaming music trough the Bluetooth Classic profile A2DP but might offer BLE services for additional features.
You always have to use a special app to communicate with the BLE part of a device. This could be an app provided by a manufacturer or a generic BLE scanner app such as nRF Connect.
As alexander.cpp already told you in his answer pairing (the exchange of keys) and bonding (saving of said keys) is not required for the communication with BLE devices and only needed if the device requires a secured connection.
Bonding (technically correct term for BLE, often called Pairing in non-technical speech) is mostly for security, we can send sensitive information because the receiver is verified and data is transferred in encrypted form.
Prefer to use bonding if the data is sensitive (means users feel uncomfortable if somebody they don't know receive their data). For example, I consider "current temperature = 25" as NOT sensitive. For detailed explanation, find "Bonding with a BLE device" in BLE guide by PunchThrough.
Also this is a good answer to a similar question: https://stackoverflow.com/a/42916081/10380092.
Your second question about background - no, bonding is not related to interaction in background.
I'm trying to establish a connection between my PC running Ubuntu and my iPhone via Bluetooth automatically when it becomes available, after being manually paired beforehand. I've seen this to be possible with certain peripherals, mainly audio. For example, my phone will automatically connect to a Bluetooth speaker when it is turned on and Bluetooth is active on my phone; another example is my phone automatically connects to my car's radio system via Bluetooth when I turn the car on.
I'm not able to connect my phone to my PC without first initiating the connection from the smartphone's Bluetooth menu. I'm thinking that I could possibly write an application for the PC to attempt to connect to the device every few minutes or something, but it seems that the phone needs to be the device to initiate the connection.
The only information that I need for what I'm trying to do ultimately is that the devices can pair successfully. Essentially I'm trying to build a sort of proximity trigger between my phone and my PC without using Wi-Fi and GPS - I can't use these for some specific reasons.
Is there any way to make this happen?
Yes this should be doable as long as you use the Background Processing feature for iOS apps. In the example I'll give below, we'll have the PC be the peripheral and the phone be the central, but you can really have it working either way. You will need to do the following:-
First initial connection needs to be performed in the foreground (this is due to iOS's background limitations).
On the iOS side, you need an application that acts as a central that scans and connects to the remove device (check this example as a starting point).
Upon connection, you need to bond with the PC. Bonding is important as it will prevent you from having to do the pairing again in the future. However, pairing/bonding is managed by the iPhone's OS so you cannot write it in your application, so the workaround is to have an encrypted characteristic on the PC side that will force the iPhone to bond (this is covered later).
On the PC side, you need to have a BlueZ script that acts as a peripheral that is always advertising. You can do this using bluetoothctl (check the examples here and here).
Before you start advertising, you need to have a GATT server on the PC side (to do this, check this example).
When registering characteristics, ensure that one of them has the encrypt-read property (you can find a full list of the properties here).
Now when you attempt to read this characteristic from the iOS side, the two devices should bond (make sure that your PC is bondable which you can do this via these commands).
Once the devices are paired, your iOS app needs to be working in the background constantly scanning and attempting to connect to the same peripheral (have a look at this and this example).
You can find more useful information at the links below:-
Getting started with Bluetooth Low Energy
The Ultimate Guide to CoreBluetooth Development
How to manage Bluetooth devices on Linux using bluetoothctl
As far as I read about the dev boards, every SoC is capable to use Bluetooth.
I didn't tested it yet, but can I use Android Things with a Bluetooth connection? My question is, how can I enable Bluetooth without an input device? If I want to enable Bluetooth on my phone (with code), I had to confirm it, but this can't be possible on Android Things.
Update: Since the release of Android Things developer preview 3, Bluetooth and BLE are now available.
Old Answer
No. You can not use Bluetooth with the current version of AndroidThings (developer preview 1).
It is said in the known issues part of the release notes that Bluetooth is currently disabled (and so is USB).
It is supposed to be included at some point, but at the moment if you try to get a BluetoothAdapter it does return null.
Android Things will use the latest version of Bluetooth called Bluetooth Low Energy and the only similarity between the two is that they have Bluetooth in the name!
Can I use Android Things with a Bluetooth connection?
Yes, well a Bluetooth Low Energy connection
https://www.link-labs.com/bluetooth-vs-bluetooth-low-energy/
In summary, Bluetooth and Bluetooth Low Energy (BLE) are used for very different purposes. Bluetooth can handle a lot of data, but consumes battery life quickly and costs a lot more. BLE is used for applications that do not need to exchange large amounts of data, and can therefore run on battery power for years at a cheaper cost. It all depends on what you’re trying to accomplish.
Everything you need to know about BLE is written here:
https://developer.android.com/guide/topics/connectivity/bluetooth-le.html
how can I enable Bluetooth without an input device?
You do not pair BLE devices like you used to with the older Bluetooth (but you can use Bonding). Check this out:
Android Bluetooth Low Energy Pairing
https://stackoverflow.com/a/20093695/413127
But as stated by #shalafi Android Things doesn't currently support Bluetooth
I'm researching iBeacons. Can I connect to iBeacons while my Bluetooth is invisible (to be protected from hacks)?
I don't have beacons to test myself and can't find any clear explanation online.
iBeacons connect to mobile phones using Bluetooth, so it is essential to have that turned on. You also need to have installed an app with iBeacon support in order to receive communication from them.
If you'd wish to use a solution that does not utilize Bluetooth, you could try out IndoorAtlas. It's an indoor navigation technology based on Earth's geomagnetic fields. It's also completely hardware-free solution, just requires you to collect fingerprints in the area you are going to use for your project.
Three points:
iBeacon technology does not rely on a bluetooth connection to your phone. Beacons are one way transmitters. They do not listen to or otherwise receive any info from your device. Beacon technology following this model is inherently privacy friendly.
Mobile devices cannot detect Bluetooth beacons with the Bluetooth radio turned off. Sorry, it is just not possible.
Properly built beacon apps will not expose your mobile device's Bluetooth info because they are receive only. Of course, other apps on your phone might use bluetooth for other purposes, so your best bet is to audit apps using bluetooth and remove any that are not doing what you want.
I just bought some beacons and tested that, The answer is YES. it is possible to read beacons mac addresses while using the phone's Bluetooth connection as invisible. Using this you will get access to your beacon in any open place without getting hacked through Bluetooth.
Thanks all for your answers.
I am trying to find a clever way to keep a BLE app active in the background on iOS 6, without breaking any of Apple's rules. I plan to use the phone as a peripheral device and another BLE circuit as the central. My app will automatically be opened when a user arrives to a building using geofencing. After that the iPhone will connect to the first BLE central device it sees (the device will be in its white list). The user will then be able to move throughout the building switching to different BLE "nodes".
My question is: What do I need to do in the background when a user is stationary at their desk so that the app does not get suspended due to memory resources?
My idea is based on this solution for a separate problem: There could potentially (not regularly) be 10-50 users in an area with only a few BLE "nodes" and I read at bluetooth.org that I could setup a dynamic connection system, basically rotating connections through all the users.
My idea is to setup a similar dynamic system where the central device (not the iPhone) disconnects the device on regular intervals (30-40 minutes) and then the iPhone will reconnect.
Is this something that some feasible? Is this against the iOS development guidelines? I was unable to find anything explicit about this. I have also asked on the iOS developer forum, but unfortunately it is not as popular as this site.
Thanks in advance!
Xcode -> Project target -> Capabilities -> Enable background mode
Check Uses Bluetooth LE Accessories
Capabilities
Also enable the following key in .plist file
Required background modes
App communicates using CoreBluetooth
Plist