Security Analysis and Improvements of Session Key Establishment for Clustered Sensor Networks

Table 2

Computation cost analysis of the proposed scheme (during sessions).

Phases	Nodes	Operations
		1024-bit RSA		SHA1	64-bit AES		163-bit ECDH
		Signing	Verification		Encryption	Decryption	Key generation	Key exchange
Hash chain setup	Gateway	1	0		0	1		1
(one time)	Cluster head	0	1	1	1	0	1	1
Key establishment	Gateway	0	0	0	0		0
( times)	Cluster head	0	0			0