We saw two activation methods. 1
One is called ABP, and the other one is called OTAA. 2
Now, when we register a device, we have to choose between these two methods. 3
And for that, we need to understand the advantages of each of them. 4
But also their differences. 5
ABP and OTAA work with keys, they're called session keys for ADP, 6
and it OTAA, the key is called the root key. 7
It's good root key because the session keys will be derived from this root key. 8
All these keys are the weakest point. 9
That means that if for some reason they appear to be exposed, then it compromises the overall security 10
of the system. 11
So the common point of these two activation methods is that the key will be kept secret as soon as they 12
are generated. 13
This is not always easy because these keys are sometimes exchanged between several parties involved 14
in the LoRaWAN communication. 15
Let's take an example of a common situation. 16
This situation works for both ABP and OTAA. 17
First, the device maker provisions the end device with new generated keys. 18
It can be root keys or session keys depending on your activation methods. 19
So he is the first who possesses the keys. 20
Then when the device is sold, the owner needs to receive the keys to register the end device. 21
So the owner will also have a copy of these keys. 22
Finally, the third entity which possesses the keys is the network server itself after the end device registration. 23
So as we can see, keys are possessed by several person or entities. 24
So for each of them we need a way to protect this key storage. 25
On the end device we use what we call secure element. 26
A secure element is a small component that you cannot access by reverse engineering. 27
As soon as an intrusion is detected, keys are erased. On the server, there's the same kind of system called 28
KMS for Key Management System. 29
Again, these systems are the more secure servers specifically used for key storage. 30
So having a secure keys storage is the common point between a ABP or OTAA. 31
Now, assuming that these keys are security stored, there's still one difference. 32
While an OTAAend devices can regenerate session keys each time it sends join request, 33
an ABP end device will keep its session keys all its life. 34
It's therefore more subject to brute force attack. 35
And that could be the case if you don't use ABP properly. 36
Okay, now I'm going to ask three questions. 37
First, how LoRaWAN prevents Replay-Attack in the next video we'll explain what the replay attack is 38
and how LoRaWAN prevents it. 39
Secondly, how can we manage the communication parameters ? 40
We will see that they are communication parameters and how're their exchange between the end device and the networks 41
server. 42
And finally, how can we change the LoRaWAN networks server ? 43
Why do I ask these three questions? 44
Because whether you use ABP or OTAA, then the answers will be different. 45
And while ABP is a bit easier to set up, we will see that these three questions are much easier to answer 46
if you use OTAA. 47
So let's start with the Replay-Attack topic and the LoRaWAN frame counter.