Common use of Complexity Analysis Clause in Contracts

Complexity Analysis. In this section, we summarize the functionality of the proposed protocol and compare the proposed protocol with ▇▇▇ et al.’s protocol. In Xie et al.’s protocol, the server needs to store a password table of all registered users for verification. In the proposed protocol, the password is embedded in h(PW a) . After receiving {h(PW a) username} in the registration phase, the server computes R = h(h(PW a) username)s−1P and stores it in the memory of a smart card, and then delivers the smart card to the user U via a secure channel. During the registration process, the server does not need to store a password table. In addition, the proposed protocol provides a securely update password phase for users to change their password freely and can resist stolen smart card attacks. As shown in Table 1, the proposed protocol can provide more unique properties such as no password or verifier table and password update freely, which were not considered in Xie et al.’s protocol. These new features are very important in implementing a practical and universal authenticated key agreement for session initiation protocol. As the protocol of Xie et al. is currently the most secure and efficient one in the literatures, we compare the proposed protocol and Xie et al.’s protocol in terms of computational costs. First, we define some notations as follows.

Complexity Analysis. In this section, we summarize the functionality of the proposed protocol and compare the proposed protocol with ▇▇▇ et al.’s protocol. In Xie et al.’s protocol, the server needs to store a password table of all registered users for verification. In the proposed protocol, the password is embedded in h(PW a) . After receiving {h(PW a) username} in the registration phase, the server computes R =  h(h(PW a) username)s−1P username)s1P and stores it in the memory of a smart card, and then delivers the smart card to the user U via a secure channel. During the registration process, the server does not need to store a password table. In addition, the proposed protocol provides a securely update password phase for users to change their password freely and can resist stolen smart card attacks. As shown in Table 1, the proposed protocol can provide more unique properties such as no password or verifier table and password update freely, which were not considered in Xie et al.’s protocol. These new features are very important in implementing a practical and universal authenticated key agreement for session initiation protocol. As the protocol of Xie et al. is currently the most secure and efficient one in the literatures, we compare the proposed protocol and Xie et al.’s protocol in terms of computational costs. First, we define some notations as follows.