## 4 Security and Performance Analyses
### Functionality Comparison  
Table 6 compares and the proposed scheme and related schemes in terms of functionality, and specifically the meeting of security requirements and resistance of potential attacks. The schemes of [PERSON] et al. [3], [PERSON] and [PERSON] [5] and [PERSON] and [PERSON] [7] are developed by using RSA and the scheme of [PERSON] et al. [10] are developed by using scalar multiplications on elliptic curves, thus requiring time-consuming computations. The schemes of [PERSON] and [PERSON] [5], [PERSON] and [PERSON] [7] and [PERSON] et al. [10] perform verification processes by using certificates. The schemes of [PERSON] et al. [3], [PERSON] et al. [8], [PERSON] et al. [13] and [PERSON] et al. [15] perform verification processes by using smartcards. The schemes of [PERSON] et al. [8], [PERSON] et al. [13] and [PERSON] et al. [15] are developed by using hash operations. The proposed scheme is developed by using hash operations and chaotic maps, which are lightweight operations. Although the schemes of [PERSON] et al. [8], [PERSON] et al. [13] and [PERSON] et al. [15] have higher efficiency in computation, their schemes do not consider PHI access and emergency exceptions, and thus cannot provide complete security requirements. Additionally, only the proposed scheme completely considers PHI uploading, access and emergency exceptions; provides completed security requirements, including updated passwords, patients' authorization and patients' control; and resists potential attacks, including password-guessing attacks, impersonation attacks, replay attacks and stolen verifier attacks. Accordingly, the proposed scheme is efficient and exhibits greater functionality than the other schemes.  
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline
**Scheme** & **[PERSON] et al.** & **[PERSON] and [PERSON]** & **[PERSON] and [PERSON]** & **[PERSON] et al.** & **[PERSON] et al.** & **[PERSON] et al.** & **[PERSON]** & **Proposed** \\  & [3] & [5] & [7] & [8] & [10] & [13] & **et al.** [15] & **Scheme** \\ \hline Used & \multirow{2}{*}{RSA} & \multirow{2}{*}{RSA} & \multirow{2}{*}{RSA} & \multirow{2}{*}{RSA/AES} & \multirow{2}{*}{Hash} & \multirow{2}{*}{ECC} & \multirow{2}{*}{Hash} & \multirow{2}{*}{Hash} & \multirow{2}{*}{ECM} \\ Algorithm & & & & & & & & \\ \hline User & \multirow{2}{*}{SC} & \multirow{2}{*}{PKC} & \multirow{2}{*}{PKC} & \multirow{2}{*}{SC} & \multirow{2}{*}{PKC} & \multirow{2}{*}{SC} & \multirow{2}{*}{SC} & \multirow{2}{*}{PCC} \\ Verification & & & & & & & & \\ \hline Providing MA & YES & NO & YES & YES & YES & YES & YES \\ \hline Providing UP & NO & NA & NA & NO & YES & YES & YES \\ \hline Providing PA & NO & NO & NO & NO & NO & NO & NO & YES \\ \hline Providing PC & NO & NO & NO & NO & NO & NO & NO & YES \\ \hline Resisting PGA & NA & NA & NA & YES & YES & YES & YES \\ \hline Resisting IA & NO & NO & YES & NO & YES & YES & YES \\ \hline Resisting RA & NO & NO & YES & YES & YES & YES & YES \\ \hline Resisting & \multirow{2}{*}{YES} & \multirow{2}{*}{NO} & \multirow{2}{*}{YES} & \multirow{2}{*}{YES} & \multirow{2}{*}{YES} & \multirow{2}{*}{YES} & \multirow{2}{*}{YES} \\ MMA & & & & & & \\ \hline Resisting SVA & NO & NA & NO & YES & YES & NO & YES \\ \hline \hline \end{tabular}
\end{table}
Table 6: Functionality comparison.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Phases** & _PHI Uploading_ & _PHI Access_ & _Emergency-Exception_ \\ \hline [PERSON] et al. [3] & \(5\) & \(5\) & \(2\) \\ \hline [PERSON] and [PERSON] [5] & \(5\) & \(4\) & \(4\) \\ \hline [PERSON] and [PERSON] [7] & \(5\) & \(5\) & \(2\) \\ \hline Proposed scheme & \(4\) & \(4\) & \(2\) \\ \hline [PERSON] et al. [8] & \(4\) & \(-\) \\ \hline [PERSON] et al. [10] & \(3\) & \(-\) \\ \hline [PERSON] et al. [13] & \(4\) & \(-\) \\ \hline [PERSON] et al. [15] & \(4\) & \(-\) \\ \hline \hline \end{tabular}
\end{table}
Table 5: Communication comparison.