Table 2. Security comparison of the proposed scheme and other related schemes.

Property	Yoon	Mun	Lee	Gope	Ahmed	Proposed
Pr1. User information related parameter privacy	O	O	X	O	X	O
Pr2. Mobile node anonymity	O	O	O	O	O	O
Pr3. Mobile node non-traceability	X	X	O	O	X	O
Pr4. Resistance to Mobile node impersonation	O	X	X	O	X	O
R1. Resistance to Replay attack	O	X	X	O	O	O
R2. Resistance to Privileged insider attack	O	X	O	X	O	O
R3. Resistance to Denial of service attack	Δ†1	X	X	X	Δ†1	O
R4. Resistance to Foreign bypass attack	O	X	O	O	O	O
R5. Resistance to Session key derived attack	O	O	O	O	X	O
R6. Forward secrecy	X	O	X	X	O	O
R7. Free and efficient password policy	X	X	X	O	Δ†2	O
R8. Session key agreement	X	O	O	O	O	O
R9. Mutual authentication	O	X	Δ†3	O	Δ†3	O

^†1 As only one of the user’s identity or password is checked in the login phase, a partial denial of service attack is possible.

^†2 The mobile node can freely set the password, but the identity verification is omitted in the password change phase.

^†3 No mutual authentication of the shared session key.