Table 2. Comparative summary: Security requirements.

Property	Jiang et al. [27]	Wen et al. [28]	Farash et al. [29]	Gope and Hwang [30]	Wu et al. [31]	Chaudhry et al. [32]	Proposed scheme
SR1	O	O	$\mathsf{X}$	O	O	$\mathsf{X}$	O
SR2	O	O	O	O	O	O	O
SR3	O	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	O	$\mathsf{X}$	O
SR4	O	$\mathsf{X}$	$\mathsf{X}$	O	O	O	O
SR5	O	O	O	O	O	O	O
SR6	O	O	$\mathsf{X}$	O	O	$\mathsf{X}$	O
SR7	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	O	O	O	O
SR8	$\mathsf{X}$	O	$\mathsf{X}$	O	$\mathsf{X}$	$\mathsf{X}$	O
SR9	$\mathsf{X}$	$\mathsf{X}$	O	O	O	O	O
SR10	O	O	O	O	O	O	O
SR11	O	O	$\mathsf{X}$	O	O	$\mathsf{X}$	O
SR12	O	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	O	O	O
SR13	O	O	O	O	O	O	O
SR14	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	O	$\mathsf{X}$	O
SR15	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	$\mathsf{X}$	O

SR₁: user anonymity; SR₂: untraceability; SR₃: resistance to stolen-mobile device or smart card attack; SR₄: mutual authentication; SR₅: session key agreement; SR₆: resistance to impersonation attack; SR₇: resistance to replay attack; SR₈: local user verification process; SR₉: resistance to stolen-verifier attack; SR₁₀: resistance to privileged-insider attack; SR₁₁: user-friendly password change; SR₁₂: forward secrecy; SR₁₃: resistance to foreign bypass attack; SR₁₄: does not need time synchronization; SR₁₅: provision of the revocation phase;