Table 4: Comparison of computation overhead in initialization phase.

Chen et al.'s protocol Our protocol

Random number ( / / )0/0/0 1/1/0
Symmetric encryption/decryption ( / / )0/0/0 0/0/2
Modular exponentiation ( / / ) 1/1/2 0/0/0
Hash operation ( / / )1/1/4 1/1/2
Chebyshev polynomial computing ( / / )0/0/0 1/1/0