Authentication Phase. We can think of the authentica- tion phase of Li et al.’s scheme as a two-pass protocol. The individual steps are outlined below:
Authentication Phase. The various steps of the authen- tication phase are depicted in Fig. 4 and are as follows:
Authentication Phase. Consider an UAV that has been assigned to collect field information from a particular region. In each region, a MEC operator selected by the USP helps the UAV in transfer- ring/receiving packets. In this phase of the proposed scheme, both the UAV and USP authenticate each other and establish a session key for secure communication. In this regard, the MEC operator helps them in exchanging the communication messages. The detailed description of the phase is as follows:
Authentication Phase. The authentication phase aims to mutually authenticate both of the sensor nodes and the remote user. To communicate the health-related data to the remote user, each sensor must execute the authentication process. The proposed scheme supports two cases of sensors authentication. The first case when the sensor nodes are not in the same location as the remote user, and in the second case, they are in the same location. The proposed authentication and key agreement scheme is as follows (see Figure 3): • The sensor node initiates the authentication phase, it generates a random nonce N on 8 bytes and sends a message composed of the generated nonce N, its masked identity MSIdi, and a h(MSIdi, N, Idi) to the remote user. • Upon receiving the message by the remote user, the message is verified by checking whether received hash is equal to the computed hash. If the matching is successful, the remote user generates a random nonce M on 8 bytes, else it is an authentication failure. • The remote user checks the location of the sensor node. If the remote user cannot reach the sensor node in his Wi-Fi covered area, then: Case ‘not in the area’: • The remote user transmits to the gateway node a message composed by the masked identity of the sensor node MSIdi, the received nonce N, the nonce M, and a h(MSIdi, N, M). • ⊕ Upon receiving the message by the gateway node, it verifies the message by checking whether the received hash is equal to the computed hash. If the check is successful, the gateway node generates a random nonce S on 8 bytes, and applies an XOR with the received nonce N: (T = N S). Then, it sends to the remote user a message composed of the received nonces N and M, the computed value T and a h(M, Xxx, S), otherwise the authentication fails. ⊕ • When the remote user receives the message, the nonce value S is computed as follows: (S = N T) and the message is verified by checking whether the received hash is equal to the computed hash. If the check is successful, the remote user also generates a random nonce W on 8 bytes, applies an XOR with value S as:
Authentication Phase. When user U wishes to login to the server, it must inserts its smart card to a card reader and inputs its username and password PW . Then the smart card and the server cooperate to perform the following steps as shown in Fig1. User U (Username, PW , Smartcard (R, a)) Server (s) 1. b ∈ Z * , V = bR + h(username)P , W = bh(h(PW a) username)P R p REQUEST (username,V ,W ) pub 2. X = h(username)P ? W ' = s2 (V − X ) , W =W ' If the equation holds, c ∈ Z * , r ∈ Z * R p R p S = cP , K = cs(V − X ) SK = h1 (K r username) Auth = h (K W ' r SK ) s 2 CHALLENGE(realm, Auths , S, r)
Authentication Phase. During the authentication process, the user Ui and the SIP server S perform the following steps to achieve mutual authentication and key negotiation. Step A1: Ui S : REQUEST (IDi , C4 , C6 ) First, the user Ui inserts its smartcard into the smartcard reader, and enters its identity IDi and its password PWi. Then the smartcard computes C2 C3 h(PWi r) h(IDi s) by using the input password PWi and the secret information (C3, r) stored in the smartcard. After that, the smartcard chooses a high entropy random integer r1 and calculates C4 r1P and C5 r1C2 Ppub . And then it selects a random integer r2 and computes X0 x(X0 ) (x(XXx x) x0 (X0 )x (C5 ) y ) , where
Authentication Phase. When user U wishes to login to the server, it must inserts its smart card to a card reader and inputs its username and password PW . Then the smart card and the server cooperate to perform the following steps as shown in Fig1. User U (Username, PW , Smartcard (R, a)) Server (s) 1. b Z * , V bR h(username)P , W bh(h(PW a) username)P R p REQUEST (username,V ,W ) pub
Authentication Phase. In this phase, the mobile user MN and a foreign agent FA can authenticate each other and share a session key K for the subsequent secret communication. When a mobile user MN roams into a new foreign network and wants to access service, the following steps are performed.
Authentication Phase. We can think of the authentication phase of Li et al.’s scheme as a two-pass protocol. The individual steps are outlined be- low:
Authentication Phase. The various steps of the authentication phase are depicted in Fig. 4 and are as follows:
