networking - validation in p2p communication -

Let's say that in each of my "networks" of users, each node can only create a hashed code (generated from the ID of the node).

Now, the node sends a node B. This hash code. The node is no longer a boss, but b is still a string, so node decides to invoice a system and sends the same code to node. How does the node know that A has done an illegal operation?

Can you validate operation only after communicating with node? (Communication with the server or other nodes)

thanks

I think That's your question:

How can I prevent node id theft / forgery in a P2P overlay network?

The answer is:

Use of public key cryptography.