My question is based on the specification of the protocol LoRaWAN and especially on the part 6.2.5 Join-accept message.
It is said that the join-accept message is encrypted using AES ECB. This is (normally) a single message created like that:
aes128_decrypt(AppKey, AppNonce | NetID | DevAddr | RFU | RxDelay | CFList | MIC)
Imagine that an attacker can listen the communications. He doesn't know
AppNonce and of course the
MIC. If the attacker can make the end device send plenty join-request messages and if the server always responds with a corresponding join-accept message, can the attacker gain knowledge of the
AppKey using the flaws in AES ECB?
Disclaimer: sorry if I'm not clear, cryptography is not my speciality.