Formal Security Analysis and Improvement Based on LonTalk Authentication Protocol

Algorithm 5

Send_MSG5 ().

(1)	idb, msg4send = Split (msg4), where msg4 is sent from sender
(2)	msg4send = {msg4con, kbs}
	if kbs = kbs’ then
	msg4con = Decrypt (msg4send, kbs’)
	then return Fail
(3)	id2, y, na, nb = Split (msg4con)
	compute timestamp = CurrentTime ()
	msg5sendAcon = combine (nb, na, y, timestamp)
(4)	msg5senda = Encrypt (msg5sendacon, kas)
	msg5con = Combine (nb, msg5senda)
	msg5 = Encrypt (msg5con, kbs)
	Send (msg5)