Issue link: https://read.uberflip.com/i/1428383
LoRaWAN 1.0.3 Specification ©2018 LoRa™ Alliance Page 34 of 72 The authors reserve the right to change specifications without notice. 6.2 Over-the-Air Activation 942 For over-the-air activation, end-devices must follow a join procedure prior to participating in 943 data exchanges with the network server. An end-device has to go through a new join 944 procedure every time it has lost the session context information. 945 The join procedure requires the end-device to be personalized with the following information 946 before its starts the join procedure: a globally unique end-device identifier (DevEUI), the 947 application identifier (AppEUI), and an AES-128 key (AppKey). 948 The AppEUI is described above in 6.1.2. 949 Note: For over-the-air-activation, end-devices are not personalized with 950 any kind of network key. Instead, whenever an end-device joins a 951 network, a network session key specific for that end-device is derived to 952 encrypt and verify transmissions at the network level. This way, roaming 953 of end-devices between networks of different providers is facilitated. 954 Using both a network session key and an application session key further 955 allows federated network servers in which application data cannot be 956 read or tampered with by the network provider. 957 6.2.1 End-device identifier (DevEUI) 958 The DevEUI is a global end-device ID in IEEE EUI64 address space that uniquely identifies 959 the end-device. 960 6.2.2 Application key (AppKey) 961 The AppKey is an AES-128 root key specific to the end-device. 1 Whenever an end-device 962 joins a network via over-the-air activation, the AppKey is used to derive the session keys 963 NwkSKey and AppSKey specific for that end-device to encrypt and verify network 964 communication and application data. 965 6.2.3 Join procedure 966 From an end-device's point of view, the join procedure consists of two MAC messages 967 exchanged with the server, namely a join request and a join accept. 968 6.2.4 Join-request message 969 The join procedure is always initiated from the end-device by sending a join-request message. 970 971 Size (bytes) 8 8 2 Join Request AppEUI DevEUI DevNonce The join-request message contains the AppEUI and DevEUI of the end-device followed by a 972 nonce of 2 octets (DevNonce). 973 1. Since all end-devices end up with unrelated application keys specific for each end-device, extracting the AppKey from an end-device only compromises this one end-device.