It's probably based on the problem of malicious clients in the network consensus problem. It states that if more than a third of all clients are malicious it is

It's probably based on the problem of malicious clients in the network consensus problem. It states that if more than a third of all clients are malicious it is not possible to come to a consensus. The solution would be to have a trust of clients. Where every clients vouches for another. The most important thing is that it has to use certificates, if not you get the following problem. I am client 'c'. I heard from client 'a' that client 'b' is dirty. So I tell this to client 'd', but the truth is I'm lying. However now the problem is: Is 'a' lying about 'b' or am I ('c') lying about 'a'? However having the messages signed by the clients solves this problem.