An Improved Broadcast Authentication Protocol for Wireless Sensor Networks Based on the Self-Reinitializable Hash Chains

Algorithm 2

Authentication of fresh nodes with cluster heads.

(1)	for fresh node do
(2)	:
(3)	:
(4)	: computes and compares the fingerprints and
(5)	if the fingerprint is true then
	if the fingerprint is true then
(6)	: , where
(7)	: , where
(8)	else
(9)	: , where
(10)	end if
(11)	else
(12)	if the fingerprint is true then
(13)	: , where
(14)	else
(15)	Authentication failure
(16)	end if
(17)	end if
(18)	end for