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Merge pull request #156 from unknownconstant/master
BLE Pairing and Encryption
2 parents b39ac7e + 3dd53d1 commit 8f9e785

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‎examples/Peripheral/EncryptedBatteryMonitor/EncryptedBatteryMonitor.ino‎

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/*
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Battery Monitor
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This example creates a BLE peripheral with the standard battery service and
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level characteristic. The A0 pin is used to calculate the battery level.
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The circuit:
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- Arduino MKR WiFi 1010, Arduino Uno WiFi Rev2 board, Arduino Nano 33 IoT,
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Arduino Nano 33 BLE, or Arduino Nano 33 BLE Sense board.
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You can use a generic BLE central app, like LightBlue (iOS and Android) or
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nRF Connect (Android), to interact with the services and characteristics
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created in this sketch.
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This example code is in the public domain.
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*/
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#include <ArduinoBLE.h>
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#define PAIR_BUTTON 3 // button for pairing
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#define PAIR_LED 24 // LED used to signal pairing
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#define PAIR_LED_ON LOW // Blue LED on Nano BLE has inverted logic
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#define PAIR_INTERVAL 30000 // interval for pairing after button press in ms
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#define CTRL_LED LED_BUILTIN
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// BLE Battery Service
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BLEService batteryService("180F");
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// BLE Battery Level Characteristic
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BLEUnsignedCharCharacteristic batteryLevelChar("2A19", // standard 16-bit characteristic UUID
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BLERead | BLENotify); // remote clients will be able to get notifications if this characteristic changes
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BLEStringCharacteristic stringcharacteristic("183E", BLERead | BLEWrite, 31);
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// Add BLEEncryption tag to require pairing. This controls the LED.
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BLEUnsignedCharCharacteristic secretValue("2a3F", BLERead | BLEWrite | BLEEncryption);
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int oldBatteryLevel = 0; // last battery level reading from analog input
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unsigned long previousMillis = 0; // last time the battery level was checked, in ms
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unsigned long pairingStarted = 0; // pairing start time when button is pressed
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bool wasConnected = 0;
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bool acceptOrReject = true;
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void setup() {
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Serial.begin(9600); // initialize serial communication
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while (!Serial);
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pinMode(CTRL_LED, OUTPUT); // initialize the built-in LED pin to indicate when a central is connected
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pinMode(PAIR_LED, OUTPUT);
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pinMode(PAIR_BUTTON, INPUT_PULLUP);
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Serial.println("Serial connected");
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// Callback function with confirmation code when new device is pairing.
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BLE.setDisplayCode([](uint32_t confirmCode){
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Serial.println("New device pairing request.");
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Serial.print("Confirm code matches pairing device: ");
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char code[6];
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sprintf(code, "%06d", confirmCode);
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Serial.println(code);
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});
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// Callback to allow accepting or rejecting pairing
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BLE.setBinaryConfirmPairing([&acceptOrReject](){
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Serial.print("Should we confirm pairing? ");
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delay(5000);
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if(acceptOrReject){
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acceptOrReject = false;
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Serial.println("yes");
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return true;
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}else{
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acceptOrReject = true;
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Serial.println("no");
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return false;
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}
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});
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// IRKs are keys that identify the true owner of a random mac address.
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// Add IRKs of devices you are bonded with.
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BLE.setGetIRKs([](uint8_t* nIRKs, uint8_t** BDaddrTypes, uint8_t*** BDAddrs, uint8_t*** IRKs){
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// Set to number of devices
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*nIRKs = 2;
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*BDAddrs = new uint8_t*[*nIRKs];
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*IRKs = new uint8_t*[*nIRKs];
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*BDaddrTypes = new uint8_t[*nIRKs];
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// Set these to the mac and IRK for your bonded devices as printed in the serial console after bonding.
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uint8_t device1Mac[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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uint8_t device1IRK[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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uint8_t device2Mac[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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uint8_t device2IRK[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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(*BDaddrTypes)[0] = 0; // Type 0 is for pubc address, type 1 is for static random
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(*BDAddrs)[0] = new uint8_t[6];
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(*IRKs)[0] = new uint8_t[16];
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memcpy((*IRKs)[0] , device1IRK,16);
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memcpy((*BDAddrs)[0], device1Mac, 6);
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(*BDaddrTypes)[1] = 0;
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(*BDAddrs)[1] = new uint8_t[6];
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(*IRKs)[1] = new uint8_t[16];
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memcpy((*IRKs)[1] , device2IRK,16);
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memcpy((*BDAddrs)[1], device2Mac, 6);
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return 1;
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});
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// The LTK is the secret key which is used to encrypt bluetooth traffic
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BLE.setGetLTK([](uint8_t* address, uint8_t* LTK){
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// address is input
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Serial.print("Received request for address: ");
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btct.printBytes(address,6);
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// Set these to the MAC and LTK of your devices after bonding.
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uint8_t device1Mac[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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uint8_t device1LTK[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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uint8_t device2Mac[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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uint8_t device2LTK[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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if(memcmp(device1Mac, address, 6) == 0) {
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memcpy(LTK, device1LTK, 16);
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return 1;
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}else if(memcmp(device2Mac, address, 6) == 0) {
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memcpy(LTK, device2LTK, 16);
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return 1;
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}
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return 0;
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});
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BLE.setStoreIRK([](uint8_t* address, uint8_t* IRK){
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Serial.print(F("New device with MAC : "));
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btct.printBytes(address,6);
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Serial.print(F("Need to store IRK : "));
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btct.printBytes(IRK,16);
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return 1;
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});
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BLE.setStoreLTK([](uint8_t* address, uint8_t* LTK){
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Serial.print(F("New device with MAC : "));
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btct.printBytes(address,6);
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Serial.print(F("Need to store LTK : "));
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btct.printBytes(LTK,16);
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return 1;
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});
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while(1){
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// begin initialization
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if (!BLE.begin()) {
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Serial.println("starting BLE failed!");
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delay(200);
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continue;
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}
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Serial.println("BT init");
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delay(200);
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/* Set a local name for the BLE device
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This name will appear in advertising packets
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and can be used by remote devices to identify this BLE device
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The name can be changed but maybe be truncated based on space left in advertisement packet
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*/
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BLE.setDeviceName("Arduino");
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BLE.setLocalName("BatteryMonitor");
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BLE.setAdvertisedService(batteryService); // add the service UUID
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batteryService.addCharacteristic(batteryLevelChar); // add the battery level characteristic
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batteryService.addCharacteristic(stringcharacteristic);
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batteryService.addCharacteristic(secretValue);
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BLE.addService(batteryService); // Add the battery service
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batteryLevelChar.writeValue(oldBatteryLevel); // set initial value for this characteristic
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char* stringCharValue = new char[32];
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stringCharValue = "string";
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stringcharacteristic.writeValue(stringCharValue);
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secretValue.writeValue(0);
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delay(1000);
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// prevent pairing until button is pressed (will show a pairing rejected message)
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BLE.setPairable(false);
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/* Start advertising BLE. It will start continuously transmitting BLE
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advertising packets and will be visible to remote BLE central devices
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until it receives a new connection */
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// start advertising
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if(!BLE.advertise()){
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Serial.println("failed to advertise bluetooth.");
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BLE.stopAdvertise();
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delay(500);
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}else{
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Serial.println("advertising...");
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break;
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}
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BLE.end();
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delay(100);
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}
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}
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void loop() {
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// wait for a BLE central
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BLEDevice central = BLE.central();
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// If button is pressed, allow pairing for 30 sec
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if (!BLE.pairable() && digitalRead(PAIR_BUTTON) == LOW){
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pairingStarted = millis();
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BLE.setPairable(Pairable::ONCE);
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Serial.println("Accepting pairing for 30s");
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} else if (BLE.pairable() && millis() > pairingStarted + PAIR_INTERVAL){
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BLE.setPairable(false);
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Serial.println("No longer accepting pairing");
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}
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// Make LED blink while pairing is allowed
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digitalWrite(PAIR_LED, (BLE.pairable() ? (millis()%400)<200 : BLE.paired()) ? PAIR_LED_ON : !PAIR_LED_ON);
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// if a central is connected to the peripheral:
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if (central && central.connected()) {
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if (!wasConnected){
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wasConnected = true;
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Serial.print("Connected to central: ");
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// print the central's BT address:
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Serial.println(central.address());
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}
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// check the battery level every 200ms
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// while the central is connected:
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long currentMillis = millis();
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// if 200ms have passed, check the battery level:
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if (currentMillis - previousMillis >= 1000) {
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previousMillis = currentMillis;
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updateBatteryLevel();
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digitalWrite(CTRL_LED, secretValue.value()>0 ? HIGH : LOW);
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}
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} else if (wasConnected){
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wasConnected = false;
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Serial.print("Disconnected from central: ");
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Serial.println(central.address());
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}
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}
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void updateBatteryLevel() {
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/* Read the current voltage level on the A0 analog input pin.
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This is used here to simulate the charge level of a battery.
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*/
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int battery = analogRead(A0);
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int batteryLevel = map(battery, 0, 1023, 0, 100);
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if (batteryLevel != oldBatteryLevel) { // if the battery level has changed
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// Serial.print("Battery Level % is now: "); // print it
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// Serial.println(batteryLevel);
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batteryLevelChar.writeValue(batteryLevel); // and update the battery level characteristic
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oldBatteryLevel = batteryLevel; // save the level for next comparison
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}
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}

‎keywords.txt‎

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@@ -77,9 +77,12 @@ setEventHandler KEYWORD2
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setAdvertisingInterval KEYWORD2
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setConnectionInterval KEYWORD2
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setConnectable KEYWORD2
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setPairable KEYWORD2
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setTimeout KEYWORD2
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debug KEYWORD2
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noDebug KEYWORD2
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pairable KEYWORD2
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paired KEYWORD2
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properties KEYWORD2
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valueSize KEYWORD2

‎src/ArduinoBLE.h‎

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#include "BLEProperty.h"
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#include "BLEStringCharacteristic.h"
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#include "BLETypedCharacteristics.h"
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#include "utility/btct.h"
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#endif

‎src/BLECharacteristic.cpp‎

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@@ -47,13 +47,13 @@ BLECharacteristic::BLECharacteristic(BLERemoteCharacteristic* remote) :
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}
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}
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50-
BLECharacteristic::BLECharacteristic(const char* uuid, uint8_t properties, int valueSize, bool fixedLength) :
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BLECharacteristic(new BLELocalCharacteristic(uuid, properties, valueSize, fixedLength))
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BLECharacteristic::BLECharacteristic(const char* uuid, uint16_t permissions, int valueSize, bool fixedLength) :
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BLECharacteristic(new BLELocalCharacteristic(uuid, permissions, valueSize, fixedLength))
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{
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}
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55-
BLECharacteristic::BLECharacteristic(const char* uuid, uint8_t properties, const char* value) :
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BLECharacteristic(new BLELocalCharacteristic(uuid, properties, value))
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BLECharacteristic::BLECharacteristic(const char* uuid, uint16_t permissions, const char* value) :
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BLECharacteristic(new BLELocalCharacteristic(uuid, permissions, value))
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{
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}
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‎src/BLECharacteristic.h‎

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@@ -45,8 +45,8 @@ class BLERemoteCharacteristic;
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class BLECharacteristic {
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public:
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BLECharacteristic();
48-
BLECharacteristic(const char* uuid, uint8_t properties, int valueSize, bool fixedLength = false);
49-
BLECharacteristic(const char* uuid, uint8_t properties, const char* value);
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BLECharacteristic(const char* uuid, uint16_t permissions, int valueSize, bool fixedLength = false);
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BLECharacteristic(const char* uuid, uint16_t permissions, const char* value);
5050
BLECharacteristic(const BLECharacteristic& other);
5151
virtual ~BLECharacteristic();
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‎src/BLEProperty.h‎

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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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// #include <stdint.h>
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2022
#ifndef _BLE_PROPERTY_H_
2123
#define _BLE_PROPERTY_H_
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@@ -26,7 +28,52 @@ enum BLEProperty {
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BLEWriteWithoutResponse = 0x04,
2729
BLEWrite = 0x08,
2830
BLENotify = 0x10,
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BLEIndicate = 0x20
31+
BLEIndicate = 0x20,
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BLEAuthSignedWrite = 1 << 6,
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BLEExtProp = 1 << 7,
34+
};
35+
36+
enum BLEPermission {
37+
BLEEncryption = 1 << 9,
38+
BLEAuthentication = 1 << 10,
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BLEAuthorization = 1 << 11,
40+
// BLEWriteEncryption = 1 << 11,
41+
// BLEWriteAuthentication = 1 << 12,
42+
// BLEWriteAuthorization = 1 << 13,
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};
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#define ESP_GATT_CHAR_PROP_BIT_BROADCAST (1 << 0) /* 0x01 */ /* relate to BTA_GATT_CHAR_PROP_BIT_BROADCAST in bta/bta_gatt_api.h */
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#define ESP_GATT_CHAR_PROP_BIT_READ (1 << 1) /* 0x02 */ /* relate to BTA_GATT_CHAR_PROP_BIT_READ in bta/bta_gatt_api.h */
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#define ESP_GATT_CHAR_PROP_BIT_WRITE_NR (1 << 2) /* 0x04 */ /* relate to BTA_GATT_CHAR_PROP_BIT_WRITE_NR in bta/bta_gatt_api.h */
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#define ESP_GATT_CHAR_PROP_BIT_WRITE (1 << 3) /* 0x08 */ /* relate to BTA_GATT_CHAR_PROP_BIT_WRITE in bta/bta_gatt_api.h */
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#define ESP_GATT_CHAR_PROP_BIT_NOTIFY (1 << 4) /* 0x10 */ /* relate to BTA_GATT_CHAR_PROP_BIT_NOTIFY in bta/bta_gatt_api.h */
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#define ESP_GATT_CHAR_PROP_BIT_INDICATE (1 << 5) /* 0x20 */ /* relate to BTA_GATT_CHAR_PROP_BIT_INDICATE in bta/bta_gatt_api.h */
51+
#define ESP_GATT_CHAR_PROP_BIT_AUTH (1 << 6) /* 0x40 */ /* relate to BTA_GATT_CHAR_PROP_BIT_AUTH in bta/bta_gatt_api.h */
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#define ESP_GATT_CHAR_PROP_BIT_EXT_PROP (1 << 7) /* 0x80 */ /* relate to BTA_GATT_CHAR_PROP_BIT_EXT_PROP in bta/bta_gatt_api.h */
53+
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#define ESP_GATT_PERM_READ (1 << 0) /* bit 0 - 0x0001 */ /* relate to BTA_GATT_PERM_READ in bta/bta_gatt_api.h */
55+
#define ESP_GATT_PERM_READ_ENCRYPTED (1 << 1) /* bit 1 - 0x0002 */ /* relate to BTA_GATT_PERM_READ_ENCRYPTED in bta/bta_gatt_api.h */
56+
#define ESP_GATT_PERM_READ_ENC_MITM (1 << 2) /* bit 2 - 0x0004 */ /* relate to BTA_GATT_PERM_READ_ENC_MITM in bta/bta_gatt_api.h */
57+
#define ESP_GATT_PERM_WRITE (1 << 4) /* bit 4 - 0x0010 */ /* relate to BTA_GATT_PERM_WRITE in bta/bta_gatt_api.h */
58+
#define ESP_GATT_PERM_WRITE_ENCRYPTED (1 << 5) /* bit 5 - 0x0020 */ /* relate to BTA_GATT_PERM_WRITE_ENCRYPTED in bta/bta_gatt_api.h */
59+
#define ESP_GATT_PERM_WRITE_ENC_MITM (1 << 6) /* bit 6 - 0x0040 */ /* relate to BTA_GATT_PERM_WRITE_ENC_MITM in bta/bta_gatt_api.h */
60+
#define ESP_GATT_PERM_WRITE_SIGNED (1 << 7) /* bit 7 - 0x0080 */ /* relate to BTA_GATT_PERM_WRITE_SIGNED in bta/bta_gatt_api.h */
61+
#define ESP_GATT_PERM_WRITE_SIGNED_MITM (1 << 8) /* bit 8 - 0x0100 */ /* relate to BTA_GATT_PERM_WRITE_SIGNED_MITM in bta/bta_gatt_api.h */
62+
#define ESP_GATT_PERM_READ_AUTHORIZATION (1 << 9) /* bit 9 - 0x0200 */
63+
#define ESP_GATT_PERM_WRITE_AUTHORIZATION (1 << 10) /* bit 10 - 0x0400 */
64+
65+
enum BLE_GATT_PERM_ {
66+
READ = 1 << 0,
67+
READ_ENCRYPTED = 1 << 1,
68+
READ_ENC_MITM = 1 << 2,
69+
WRITE = 1 << 4,
70+
WRITE_ENCRYPTED = 1 << 5,
71+
WRITE_ENC_MITM = 1 << 6,
72+
WRITE_SIGNED = 1 << 7,
73+
WRITE_SIGNED_MITM = 1 << 8,
74+
READ_AUTHORIZATION = 1 << 9,
75+
WRITE_AUTHORIZATION = 1 << 10,
3076
};
3177

78+
3279
#endif

‎src/BLETypedCharacteristic.h‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -25,7 +25,7 @@
2525
template<typename T> class BLETypedCharacteristic : public BLECharacteristic
2626
{
2727
public:
28-
BLETypedCharacteristic(const char* uuid, unsigned char properties);
28+
BLETypedCharacteristic(const char* uuid, unsigned int permissions);
2929

3030
int writeValue(T value);
3131
int setValue(T value) { return writeValue(value); }
@@ -43,8 +43,8 @@ template<typename T> class BLETypedCharacteristic : public BLECharacteristic
4343
T byteSwap(T value);
4444
};
4545

46-
template<typename T> BLETypedCharacteristic<T>::BLETypedCharacteristic(const char* uuid, unsigned char properties) :
47-
BLECharacteristic(uuid, properties, sizeof(T), true)
46+
template<typename T> BLETypedCharacteristic<T>::BLETypedCharacteristic(const char* uuid, unsigned int permissions) :
47+
BLECharacteristic(uuid, permissions, sizeof(T), true)
4848
{
4949
T value;
5050
memset(&value, 0x00, sizeof(value));

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