Communication Overhead Cost Sample Clauses

Communication Overhead Cost. To facilitate the analysis of communication overhead, we assume the length of the IoT device’s identity, user’s identity, pseudonym identity and the corresponding password are all 128 bits. The length of the secret key, the random number, the output of hash function and message authentication code (MAC) are all 160 bits. The length of the time stamp, the ECC point multiplication and the cipher text block in symmetric encryption/decryption are 32 bits, 320 bits and 256 bits respectively. To provide sufficient security, 1024-bits modulus is used for modular exponentiation and inversion operations. Therefore, the length of modular squaring is 1024-bits. In M2MAKA-FS, the transmitted messages {EIDi, M1, M2, M3, M4, M5}, {M6, M7, M8, M9}, {M10, M11, M12, M13} and {M14, M15, M16, M17} require {256+160+160+160+160+160} = 1,056 bits, {160+160+160+160} = 640 bits, {160+160+160+160} = 640 bits and {160+160+160+256} = 736 bits, respectively. Therefore, the cumulative communication overhead of M2MAKA-FS is 3,072 bits. The cumulative overheads of Shuai et al.’s protocol, ▇▇▇▇▇ et al.’s protocol, ▇▇▇▇▇▇ et al.’s protocol, ▇▇▇▇ et al.’s protocol and Li et al.’s protocol are shown in Table 4. Although there is advantage in the communication overhead of the other protocols, it is justifiable because M2MAKA-FS offers better security and more functionality features as compared to these protocols shown in Table 2. We always believe that security is at least as important as efficiency for an AKA protocol and thus it is not advisable to significantly reduce security to increase marginal efficiency [46].