# A Survey of Internet of Things (IoT) Authentication Schemes +
## 7 Conclusions
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Ref\#** & **IoT Layer** & **Identity Context Credentials** & **Token Based?** & **Proc.** & **Arch.** & **HW.** & **Strength(+)/Weakness(–)** \\ \hline
[94] & N + P & Encryption/Symmetric + Asymmetric + Hashing & ✓(Spanish cards) & eID & 2 & C/H & E & +Resistance to replay, DDoS attacks and improve confidentiality and non-repudiation. \\
[94] & N + P & Encryption/Symmetric + Asymmetric + Hashing & ✓(Spanish cards) & eID & 2 & C/H & E & +Computation and communication overhead is low \\  & & & & & & +Location privacy is considered & \\  & & & & & & & -Identity privacy is not considered \\ \hline
[95] & N + P & Encryption/Symmetric(AES) + Asymmetric (DH)+Hashing & ✓(transaction ID) & 2 & C/H & I & +No rely on third parties for shared key management, instead a DH based exchange mechanism is used. +Resistance to impersonation and MITM attacks. & \\  & & & & & & +Resistance to impersonation and MITM attacks. & \\  & & & & & & -Identity privacy is not considered \\ \hline
[96] & N + P & Encryption/Symmetric + Asymmetric+Hashing & ✓(pseudo-identity (PsID)) & 2 & C/H & I & +Provides a node, message authentication, and privacy protection. & \\  & & & & (PsID)) & 2 & C/H & I & +Computation and communication overhead is studied. & \\  & & & & & & -Identity privacy is not considered \\ \hline
[97] & N + P & Encryption/Symmetric(AES) + Asymmetric(ECDSA) +Hashing & ✓(pseudo-identity (PsID)) & 2 & C/F & I & +Security and privacy analysis is considered +Computation and communication overhead is considered & \\  & & & & & & -Identity privacy is not considered \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Ref\#** & **IoT Layer** & **Identity Context Credentials** & **Token Based?** & **Proc.** & **Arch.** & **HW.** & **Strength(+)/Weakness(\(-\))** \\ \hline
[90] & N + P & Encryption/Asymmetric + Hashing & ✓(pseudo-identity (PsID)) & 2 & C/F & I &
\begin{tabular}{c} +Resistance to DoS, ReplaySybil, and False \\ message attacks. \\ +Consider privacy preservation. \\ -Non-repudiation attack is not considered \\ \end{tabular} \\ \hline
[91] & N + P & Encryption/symmetric + Hashing & ✓(identity) & 2 & C/H & I &
\begin{tabular}{c} +Resistance to Movement tracking, Replay, \\ and Message modification attacks. \\ -Location privacy is not considered \\ \end{tabular} \\ \hline
[100] & N + P & Encryption/Symmetric + Asymmetric + Hashing & No/TLS & 2 & C/F & I &
\begin{tabular}{c} +Resistance to Impersonation and \\ MITH attacks. \\ -Privacy is not considered \\ \end{tabular} \\ \hline
[89] & N + P & Encryption/Symmetric + Asymmetric + Hashing & x & 2 & C/F & I &
\begin{tabular}{c} +Resistance to Substitution attack (a kind of \\ MITH attack). \\ -No evaluation for message delay and \\ verification delay \\ \end{tabular} \\ \hline
[80] & A + N + P & Encryption/Asymmetric + Hashing & x & 2 & C/F & I &
\begin{tabular}{c} +Efficient use of one-way hash \\ +Resistance to message forging attacks \\ +Reduce the storage \\ -Increase the computation overhead \\ although it is balanced between sender \\ and receiver \\ -Privacy is not considered. \\ -Integrity and Confidentiality are not considered. \\ \end{tabular} \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._