BOSCO.py

from Messages.Message import Message


class BOSCO:

    name = "BOSCO Protocol"

    def __init__(self, **kargs):
        self.env = kargs["env"]
        self.pki = kargs["pki"]
        self.pki.register(self)
        self.input = None

    def run_node(self):
        round = self.env.get_round()
        myid = self.env.get_id(self)
        flag = 0
        if round == 0:
            self.input = self.env.get_input(myid)
            self.env.put_broadcast(self, self.pki.sign(
                self, Message(myid, self.input)))
        else:
            if flag:
                self.env.get_input_msgs(self)
                self.env.put_broadcast(self, self.pki.sign(
                    self, Message(myid, self.input)))
            else:
                msgs = self.env.get_input_msgs(self)
                d = {}
                for msg in msgs:
                    if(not self.pki.verify(msg)):
                        raise RuntimeError
                    key = msg.get_extraction()
                    if key not in d:
                        d[key] = 0
                    d[key] = d[key]+1
                if not d:
                    raise RuntimeError
                d_sorted = sorted(
                    d.items(), key=lambda kv: kv[1], reverse=True)
                if(d_sorted[0][1] >= (self.env.get_n()-self.env.get_f())):
                    self.env.put_output(self, d_sorted[0][0])
                    self.input = d_sorted[0][0]
                    self.env.put_broadcast(self, self.pki.sign(
                        self, Message(myid, self.input)))
                elif (d_sorted[0][1] > (self.env.get_n()-self.env.get_f())/2):
                    if len(d_sorted) > 1 and d_sorted[1][1] > (self.env.get_n()-self.env.get_f())/2:
                        self.env.put_broadcast(self, self.pki.sign(
                            self, Message(myid, self.input)))
                    else:
                        self.input = d_sorted[0][0]
                        self.env.put_broadcast(self, self.pki.sign(
                            self, Message(myid, self.input)))