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Table 1: Efficiency of IDSC.
PC - Denotes Pre-Computable
Waters Kenny and Schuldt Our
Encryption Signature Signcryption*
Pairings 3(1PC) 4(1PC) 7(2PC)
G
1
Exponentiations 2 3 3
G
2
Exponentiations 1 - 1
Signcryption Size G
2
× G
2
1
G
3
1
G
2
× G
4
1
Public Parameter Size G
4
1
× G
n
u
1
G
5
1
× G
n
u
1
× G
n
m
1
G
4
1
× G
n
u
1
public parameter size, signcryption size and exponen-
tiations. One of the shortcomings of our scheme is
its public parameter size. An open problem is to con-
struct a signcryption with compact public parameter
size.
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