User Anonymity. For schemes [6, 7, 12], the identity IDC of the client C is transferred by plaintext, so an attacker can easily obtain the identity of the client. Thus user anonymity cannot be protected.
User Anonymity. No entity except the trusted gateway nodes can obtain any information about the identity of the users during the authentication phase.
User Anonymity. Basedonthedesignoftheproposedprotocol,theexcelle ntpropertyofuseranonymitycanbeguaranteedateveryph ase.Weusedmaskingfortherealidentity via a public channel, and no attacker can compromise user's real identity by launching security attacks. First, in the login phase, patient's real identity is included in YA = ê(RA, F) ⨁XXX.Thus, the attacker cannot reveal XXX without using d to XA due to elliptic curve discrete logarithm problem. Also, all of the identities are transmitted in cipher format instead of plaintext, and these identities will be randomized at each new session. As a result, the proposed protocol can provide user anonymity.
User Anonymity. Suppose that an attacker has intercepted Ui’s authentication messages {CIDi, V, M1}, {M2, W} and {M3}. After that, the adversary may try to retrieve any static parameter from these messages, but these messages are all session-variant and indeed random strings due to the randomness of v or w. Accordingly, without knowing the random numbers, the attacker will face to solve the discrete logarithm problem to retrieve the correct value of IDi from CIDi, while IDi is the only static element corresponding to Ui in the transmitted messages. Hence, the proposed scheme can preserve user anonymity.
User Anonymity. This user's identity and his location are valuable information, and identity should be concealed from potential eavesdroppers when the true identity is compromised when roaming. The disclosure of this sensitive information may result in serious consequences, especially if the subscriber is a very important person (VIP). Anonymity is currently provided by use of temporary identities for communication. However, in the case of new registration and roaming, the genuine identity is necessary. The existing mechanisms of GSM and UMTS have experienced some security breaches, which may cause the protection to this sensitive information to fail (Ford, 1994) (ISO, 1996).
User Anonymity. To preserve user’s identity privacy, the proposed protocol should provide user anonymity, i.e., an adversary cannot intercept the real identities of users during the authentication process.
User Anonymity. Based on the design of the proposed protocol, the excellent property of user anonymity can be guaranteed at every phase. The protocol used masking for the real identity via a public channel, and no attacker can compromise user's real identity by launching security attacks. In the login phase, patient's real identity is included in YA = ê(RA, F) XOR XXX. Thus, the attacker cannot reveal XXX without having a power to perform ECDLP due to the bilinear pairing. Furthermore, all of the identities are transmitted in encrypted form instead of the message and these identities will be randomized at each session. As a result, the proposed protocol can provide user anonymity.
User Anonymity. We adopt two strategies to protect the user’s identity from disclosing. One is the masked identity h(IDi, Xk) with the secret key Xk of GWN. Note that the key is essentially a random number generated by GWN and thus it is computationally infeasible for A to extract the user’s identity in plaintext. Another is directly the use of dynamic identity selected by GWN, which is hashed in the open channel. In essence, the random identity is no relation with the real one. Consequently, compromise of released one influences nothing on the actual identity of Xx. Therefore, the proposed scheme mechanism is a dynamic identification process and we will verify the point later in simulation.
User Anonymity. The real identity IDi of the Vi is hidden in the ciphertext Ci = ER∗ (IDi, DIDj, PIDj, Ti), where ri = H2(αi||si||Ti), Ri = ri · P and Ri∗ = riPpub. If the A Bi = H2(H1(UIDi PWi) s IDi), needs to known both A A the secret key si and the user identity UIDi. If executes qs times Corrupt queries for guessing the IDi/PWi or matching the secret key si and the user identity UIDi, and has reached the upper limit, the probability that wins game G3 is: s q
