Thanks ! I finally successed to use signing but it was quite difficult because I speak just a little bit english and The only step by step guide that I've found is for mySensor V1.5 and not for 2.0.

My difficulty comes that I didn't understand that I had to flash EEPROM with Keys(with SecurityPersonnalizer.ino) and then flash my sketch. Finally, I added in Gateway and Sketches these lines

#define MY_SIGNING_SOFT
#define MY_SIGNING_SOFT_RANDOMSEED_PIN 7
#define MY_SIGNING_REQUEST_SIGNATURES

And now it works !!

I've just noticed some communication errors sometimes... Perhaps it's because signing protocole needs more messages exchanges
between nodes and gateway.

Hello,

I have just update my network to mysensors 2.0 and my network is growing up. I think its time to secure it. First, I've changed the channel of RF24, then I've uncommented the line "//#define MY_RF24_ENABLE_ENCRYPTION" in MyConfig.h file.

It's also noticed "and all must be personalized with the same AES key". But where can I setup this AES key and which format for it ?

Thanks