## 3 Countermeasures
### Entity Attributes-Based Countermeasures
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Ref.** & **Threat Area** & **Countermeasure** & \multicolumn{2}{c}{**Attributes**} & \multicolumn{2}{c}{**Limitations**} \\ \hline
[41] & Confidentiality & Paillier cryptosystem & \(\bullet\) & Employs three algorithms: generation of keys, encryption and decryption & \(\bullet\) & Processing Power requirement \\  & & & \(\bullet\) & Traditional approach of random prime numbers & \(\bullet\) & MitM vulnerability \\  & & & \(\bullet\) & Traditional approach of random prime numbers & \(\bullet\) & Quantum Computing-based \\ \hline
[57] & Authentication & RSA & \(\bullet\) & Group-based signature architecture & \(\bullet\) & Processing in IoT \\  & & & & & \(\bullet\) & Resistant to Quantum \\  & & & & & Computing \\ \hline
[64] & Authentication & Quantum secure ring signature & \(\bullet\) & Chameleon hash function & \(\bullet\) & Limited scalability \\  & & signature & \(\bullet\) & Accumulator and ZK arguments & \(\bullet\) & Linear growth of signature size \\  & & & & \(\bullet\) & Backward compatibility issues \\ \hline
[37] & Authentication & Proxy ring signature & \(\bullet\) & Handover authentication & \(\bullet\) & Unsecure data at edge server \\  & & & \(\bullet\) & ECC algorithm & \(\bullet\) & Processing cost at edge server \\  & & & & & \(\bullet\) & Historical data migration \\  & & & & & problem \\ \hline
[67] & Authentication & Key exchange & \(\bullet\) & Digital signature-based key exchange & \(\bullet\) & Processing issue at IoT device \\  & & & \(\bullet\) & AES encryption & \(\bullet\) & MEC exploitation with quantum computing \\  & & & & & \(\bullet\) & Authentication delay is above \\  & & & & & \(\bullet\) & 1 ms \\ \hline
[68] & Confidentiality & Lightweight cryptography & \(\bullet\) & Cryptography with the color & \(\bullet\) & Specific application of multimedia data \\  & & & \(\bullet\) & Image-based scheme & \(\bullet\) & Does not cover network exploits \\  & & & \(\bullet\) & Multiple secret sharing & \(\bullet\) & Does not cover network exploits \\  & & & & \(\bullet\) & Hybrid Particle Swarm & \\  & & & & Optimization-based Cuckoo Search & & \\  & & & & Optimization Algorithm & & \\ \hline
[69] & Confidentiality & Random number generation & \(\bullet\) & PRNG algorithm & \(\bullet\) & Specific to stream cipher \\  & & & \(\bullet\) & XOR-shift operation & \(\bullet\) & Does not explain memory and \\  & & & \(\bullet\) & 23.8 Tbps throughput & \(\bullet\) & key sharing \\ \hline
[70] & Authentication & Lightweight cryptography & \(\bullet\) & MEC integration in 6G architecture & \(\bullet\) & Role of CA not explained \\  & & & \(\bullet\) & Device-to-Device (D2D) communications & \(\bullet\) & Key generation and management \\ \hline
[71] & Confidentiality & Stream cipher & \(\bullet\) & FPGA-based stream cipher & \(\bullet\) & Complex design \\  & & & \(\bullet\) & Reconfigurable Logic & \(\bullet\) & Memory limitations \\  & & & \(\bullet\) & Aims at a lower hardware utilization & \(\bullet\) & Cryptanalysis attacks \\ \hline
[72] & Confidentiality & Distributed encryption & \(\bullet\) & D-OMA & \(\bullet\) & Compatibility with upper layer \\  & & & \(\bullet\) & Low intercept probability & \(\bullet\) & in network \\  & & & \(\bullet\) & Physical Layer Security & \(\bullet\) & Compatibility with non-OMA \\ \hline
[73] & Confidentiality & Asymmetric encryption & \(\bullet\) & VLC-based indoor applications & \(\bullet\) & Line of sight \\  & & & \(\bullet\) & Optimum error rate & \(\bullet\) & RSA in quantum computing \\  & & & & RSA encryption keys and data lengths & \(\bullet\) & Integration issues \\ \hline
[74] & Confidentiality & AES encryption & \(\bullet\) & AI-based QoS, AES encryption for joint network optimization & \(\bullet\) & Key distribution in heterogenous IoT \\  & & & \(\bullet\) & Kalman filtering to predict future & \(\bullet\) & Short keys are vulnerable \\  & & & & harvesting power & & \\  & & & \(\bullet\) & Key length switching & & \\ \hline
[75] & Confidentiality & Post quantum KEM & \(\bullet\) & Countermeasure to quantum attacks & \(\bullet\) & Processing requirements in IoTs \\  & & & & \(\bullet\) & Delay requirements of 6G \\ \hline \hline \end{tabular}
\end{table}