# Blockchain for Future Wireless Networks: A Decade Survey
## 3 The Proposed Taxonomy for Security Attacks and Countermeasures
### Passive Attacks
After that, [PERSON] et al. [176] introduced a blockchain-enabled SDN framework that reduces the end-to-end delay in resource management. [PERSON] et al. [177] proposed blockchain-based trajectory privacy approach to protect drone communication. Moreover, in [178], the author proposed the elliptic curve Diffie-Hellman key exchange technique to protect private information in the medical field. The proposed work in [178] was further improved by [PERSON] et al. in [179] with a temper registered blockchain-based framework. They used encryption techniques, digital signatures, and hashing techniques to prevent healthcare resource loss. [PERSON] et al. [180] worked in the same field and prevented data tampering issues using blockchain-enabled cloud technology. [PERSON] et al. [181] worked for crowdsensing systems and proposed smart contract-based solutions to prevent data confidentiality, integrity, and system availability issues. Then, [PERSON] et al. [182] proposed the spherical fuzzy-weighted with zero inconsistency (FWZIC) method to prevent access control, user privacy, and authentication in healthcare. They introduced the grey relational analysis--a technique for the order of preference by similarity to ideal solution (GRATOPSIS) and the bald eagle search (BES) optimization approach for the system's security. Table 3 presents the existing blockchain-based solution for different innovative applications, such as e-healthcare and resource allocation in security and privacy perspectives of WNs. \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Year** & **Author** & **Applications** & **Security Issues** & **Approach** & **Pros** & **Cons** \\ \hline
2020 & [PERSON] et al. [170] & Wireless industrial IoT (1 floTs) & Scaricity of spectrum resources & Presented blockchain on CDMA/CA model & Introduced stochastic mode and double-spending attack on CDMA/CA & Not considered layer wise security \\ \hline
2020 & [PERSON] et al. [171] & IoT applications & Malicious jamming & Presented RAFT based blockchain network & Proposed consensus algorithm & Not considered multi-jammer problem \\ \hline
2020 & [PERSON] et al. [172] & 5G security for different technology like SDN, NFV etc & Detection and prevention of sabotage & Proposed 5G security model & Considered network and physical layer security & Other layer security is lacked \\ \hline
2020 & [PERSON] et al. [173] & e-healthcare & Data tampering & Analyzed eHealth scenario using blockchain & Presented identity model with blockchain & Did not consider real-time scenario results \\ \hline
2021 & [PERSON] et al. [174] & Unmanned aerial vehicles & Unmanned aerial privacy & Reliability and connectivity, energy efficiency, data privacy & Blockchain-based approach & Proposed drone-based architecture on 5G for with different technologies & Did not discuss security attacks \\ \hline
2021 & [PERSON] et al. [175] & Edge cache network & Data tampering and eavesdrop & Blockchain-based 6G framework & Used 6G edge caching and two-hop transmission, optimize the cashing for secure transmission & Did not incorporate a comparative analysis of the proposed transaction & Did not consider a comparative analysis of the proposed approach with existing security solutions \\ \hline
2021 & [PERSON] et al. [176] & Resource management for IoT & Energy efficiency and end-to-end delay for resource utilization & Blockchain-based SDN framework & Proposed cluster-head selection algorithm to secure network & Did not consider mobility \\ \hline
2021 & [PERSON] et al. [177] & Drone Communication & Drone ID management, privacy and trajectory protection & Presented blockchain-trajectory scheme & blockchain-trajectory & Used in military and civil-ian area & Did not cover security attacks \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Blockchain-based solution for different smart applications in security and privacy perspectives of WNs.