Actually, I am using a Cooja simulator in order to evaluate the performance of RPL based IoT. Unfortunately, I could not find a way to implement malicious nodes (Blackholed). Can someone please provide me the code of blackhole node?
You can see https://tetcos.com/file-exchange.html for some project codes and documents for blackhole/sinkhole attacks. However these are based on NetSim and you will need to adapt them for Cooja