Interdomain Identity-Based Key Agreement Schemes

Table 2

Performance comparisons in single domain.

Communication cost	[24]	[18]	[15, 16]	[17]	[19]	[25]	[27]	[26] (1)	[26] (2)	Ours
Round	2	2	2	1	1	3	3	1	2	3
Bandwidth	3	3	3	3		4			3
Computation cost	[24]	[18]	[15, 16]	[17]	[19]	[25]	[27]	[26] (1)	[26] (2)	Ours
Point addition	9	6						—
Scalar multiplication ()	8	4						—	2
Scalar multiplication ()		—			—	—	—		2	—
Pairing	4	4	4		1				4
Exponentiation	—	—		—	—	—	—	—	—	—
Increment/decrement of computation time	↓22%	↓19%	↓78%	↓98%	↑48%	↓97%	↓196%	↓98%	↓19%	—

Bandwidth: the total number of messages (points) sent by a user.
: the number of users.
From [28], 1 exponentiation ≈ 240 scalar multiplications, 1 point addition 0.12 scalar multiplication, 1 scalar multiplication in scalar multiplications, 1 scalar multiplication in 1 scalar multiplication, and 1 pairing 10 exponentiations.