Table 2 Existing approaches in Blockchain-based Spectrum Access Security.

Secure authentication and identity management

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The proposed tree-centric approach in CRNs improves spectrum allocation efficiency, managing authenticated SUs, and reducing channel access requests to 1–2 with an average delay of about 72 ms.

The study employs a tree-centric approach, where a CBS manages a tree of channels and authenticates SUs for efficient allocation, validated by extensive simulations.

The main challenge is throughput loss due to PU movement. Future work will improve sensing to better track PU activity and optimize channel allocation.

¹⁰¹

integrating blockchain-based authentication with a hybrid AES-HCC algorithm significantly enhances security in the BlockCRN-IoCV method. This approach improves the accuracy of authenticating both Primary and Secondary Users.

The study uses blockchain with AES-HCC for user authentication, DADRC for mobility, DA-TD3 for spectrum access, and BiGRU-CapsNet for secure beamforming. Performance is assessed through OMNET + + and SUMO simulations.

Limitation: Poor

Spectral efficiency.

Future directions include implementing hybrid beamforming to improve hardware, spectral, and computational efficiency.

¹⁰²

Integrating CLRSB with MFOA-ICNN boosts security and efficiency in CRNs by using cryptographic keys to distinguish trustworthy users, and reduces response time and frame loss by 18.13% and 17.81%, respectively.

The study employs CLRSB for security and MFOA-ICNN for improved spectrum sensing.

The study points out security gaps, scalability issues, and the need for better optimization.

Future work should address these problems and validate results in real-world settings.

¹⁰³

The study finds that a blockchain-based method using cryptographic keys effectively detects malicious users in CRN for IoTs, improving spectrum sensing accuracy and overall cognitive radio performance.

blockchain-based approach to digital signatures to authenticate users, leveraging cryptographic keys for secure communication. Simulations, assessed through MATLAB simulations.

Did not explore the potential computational overhead associated with cryptographic operations.

¹⁰⁴

The study finds that a blockchain-based ID management system improves security and privacy for IoT ecosystems by using self-sovereign identity and cryptography.

develops a proof-of-concept prototype using a federated blockchain platform with smart contracts to manage identities and secure data in IoT environments.

Future work aims to improve scalability and evaluate real-world performance compared to emerging solutions.

³⁴

The study shows that the new 6G security architecture, improving position-based and flexible authentication, enhances security and performance with a 94% better BER and 96% higher throughput.

The architecture is evaluated using Riverbed Modeler 17.5 simulations, focusing on secret key authentication and flexible position-based identification.

The study acknowledges the need to address limitations in the proposed security framework and suggests further exploration to enhance 6G network security.

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The study shows that combining blockchain with a cross-layer method for relay selection enhances security and trustworthiness in cognitive radio systems by effectively distinguishing reputable from non-reputable relays.

The approach uses blockchain for managing relay trustworthiness, virtual wallets for spectrum access, and algorithms for classifying relays.

Future work should enhance relay classification and blockchain efficiency, especially in dynamic environments with eavesdroppers.

Tamper-resistant spectrum sensing data

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The blockchain-based cooperative spectrum sensing (CSS) method enhances MU detection by 15% and improves spectrum management and security.

The method uses blockchain for spectrum sensing and MU identification, evaluated with metrics like sensitivity and throughput through MATLAB simulations.

Future work should address delays caused by large numbers of cognitive radios and improve real-time security management.

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The study shows that energy detection with collaborative spectrum sensing boosts spectrum utilization, improving detection by 15% for 64-QAM signals at 3 dBm SNR.

The effectiveness of energy detection is evaluated using receiver operating characteristic (ROC) curves under various conditions, with simulations conducted in MATLAB R2021b.

Future work should address noise uncertainty, concealed nodes, and the effects of fading and shadowing on SNR.

¹⁰⁸

Cognitive radio networks can improve spectrum utilization and security by allowing SUs to coexist with PUs. The NES algorithm and secure spectrum sensing enhance network efficiency.

The study uses the NES algorithm and secure spectrum sensing with blockchain to manage user interactions and node performance.

The study needs to address vulnerabilities related to wireless media exposure and potential attacks.

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The proposed blockchain-based DSA framework improves spectrum management by decentralizing the sensing and access process, reducing reliance on a single point of failure, and rewarding SUs with tokens.

The framework employs a time-slotted protocol where secondary users act as both sensing and mining nodes in a blockchain, using a heuristic policy for participation and bidding.

The system faces a trade-off between energy consumption and performance. Future research should optimize sensing and mining policies to improve energy efficiency.

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The 6GCRN–IoCV approach improves spectrum utilization, reduces collisions, and enhances communication reliability in cognitive radio networks integrated with IoCV.

Spectrum sensing with Lite-CNNs and encrypted reporting. The study validates its performance using SUMO and OMNeT + + simulation tools.

Limitations: High sensing delay = 20ms with 100 SUs, and high acquisition delay

Decentralized spectrum database

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Blockchain has the potential to improve dynamic spectrum sharing in radio spectrum management through its decentralized database, which allows data owners to retain control.

The study compares blockchain to existing spectrum management methods and evaluates its benefits for dynamic spectrum sharing.

The paper does not provide detailed case studies or address challenges like scalability and integration issues with blockchain.

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The article introduces a blockchain-based distributed database for securing spectrum sharing in cognitive radio networks, using Specoins for access.

The methods involve using blockchain for Specoin transactions, verifying with private keys, and comparing performance to the Aloha protocol under different fading conditions.

Future works will focus on the effects of additional wireless channel parameters and managing power consumption with limited resources.

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The Blockchain-based Distributed Electromagnetic Spectrum Database (BC-DSDB) reduces data redundancy and enhances spectrum management in CRNs.

Minimum Average Distance (MAD) method and the BC-DSDB with Proof of High Confidence (POHC).

Scalability, security, and real-world implementation challenges of the BC-DSDB are not addressed.

Smart contracts for spectrum allocation

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The research proposes a Blockchain-based platform with a spectral token to manage dynamic spectrum access, reduce interference, and ensure compensation for primary users.

The platform uses Ethereum Blockchain and smart contracts to manage spectrum sharing and leasing, with a proof of concept demonstrating its performance.

Future work will explore complex leasing strategies and faster dynamic spectrum access.

⁵³

A blockchain-based framework is proposed for managing spectrum resources in CPSSs, addressing spectrum scarcity and competition using edge computing for non-real-time data.

The framework employs a multi-ring private blockchain for spectrum mining and leasing, with smart contracts to secure transactions and rewards in virtual currency and spectrum licenses.

The framework lacks real-time data handling and consensus algorithm considerations, with future work focusing on spectrum auctions and alternative algorithms.

¹¹¹

The research proposes Block6Tel, a blockchain-based system for 6G spectrum allocation, to improve fairness, reduce auction delays, and prevent collusive bidding.

Block6Tel combines a 6G protocol stack and blockchain-based auction with smart contracts for resource allocation.

Scalability challenges are not addressed.

Secure communication with smart contracts

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The article presents a blockchain-based framework for secure spectrum sharing in NGTNs, enhancing privacy and resource management.

The framework employs blockchain and smart contracts, with a tokenization model for privacy.

Future research should explore scalability, spectrum pricing, consensus algorithms, and enhancing smart contracts.

⁸⁹

The research presents a case study on using blockchain, AI, and 6G technology to enhance security and data integrity in public safety applications, addressing issues like data attacks and privacy.

The study employs blockchain for security, smart contracts for automation, and IPFS for storage, and uses Google Colaboratory and MATLAB for machine learning and communication.

The study did not explore CR technology or consider throughput. Future work will aim to resolve issues and enhance the performance of blockchain-based 6G systems.

¹¹²

The paper introduces a dynamic spectrum-sharing scheme for cell-free massive MIMO networks, utilizing blockchain and smart contracts to improve spectrum allocation and transparency.

A Stackelberg game formulation is used for bandwidth allocation and pricing, with blockchain ensuring transparent and secure transactions.

Future research will evaluate various blockchain models to enhance scalability, security, and efficiency in spectrum trading.

¹¹³

The paper presents a blockchain-based solution using Ethereum to secure smart grid communications, ensuring privacy and data integrity between smart meters and utilities.

The framework employs Ethereum and smart contracts to validate smart meter authenticity and secure data reporting.

Future research will address these challenges, integrate renewable energy sources, and test the solution with real smart grid data.

Consensus mechanisms for decision-making

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The BSM-6G model integrates blockchain with Cognitive Radio to improve dynamic spectrum management in 6G networks, addressing issues of transparency, interoperability, and scalability.

The model uses an interoperable blockchain Oracle and the Proof-of-History (PoH) consensus protocol for efficient spectrum management.

Future work will enhance Oracle automation, improve band subdivision, and explore custom blockchain networks for better spectrum management.

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The CBRS-Blockchain model cuts cost, enhances privacy with ring signatures, and improves reliability with proof-of-strategy, avoiding single points of failure.

The model and its performance are evaluated through MATLAB simulations.

Future work should explore user interactions, predict incumbent behavior, and optimize spectrum use for PAL users.

Immutable record of spectrum transactions

¹¹⁶

Blockchain-based spectrum management improves security and efficiency with its decentralized and tamper-resistant design, optimizing transaction efficiency and reducing validation overhead.

The study compares blockchain with traditional spectrum management, proposes a new architecture, and tests an interference-based consensus and validation mechanism through simulations.

Further research should focus on real-world implementation and integrating blockchain with new technologies.

¹¹⁷

The scheme ensures transaction authenticity and user participation in cognitive radio networks by using money-locking and a reputation parameter to penalize unreliable users while protecting reliable ones.

Blockchain smart contracts secure transactions, a money-locking scheme penalizes failures, and a reputation parameter manages user reliability.

Future work may use Federated Learning to optimize penalty thresholds and reputation calculations, enhancing transaction accuracy and adaptability.

Resilience against DoS attacks

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The STBC protocol increases spectrum utilization by 30%, speeds up transaction confirmation by 125x, and reduces energy consumption, while also protecting against DDoS attacks and ensuring high security.

The protocol features a new consensus mechanism for faster transactions, uses sharding for better efficiency, and includes temporarily anonymous transactions for privacy and DDoS protection.

The STBC protocol handles only spectrum transaction consensus, lacks a full management-auction system, and depends on strong security assumptions that require further improvement.

¹¹⁹

The blockchain-based security model for CRAHNs reduces delays by 18.5%, boosts throughput by 19.5%, improves PDR by 19.4%, saves 12.5% in energy, and mitigates DDoS attacks.

The model uses blockchain and a Mayfly Optimizer for efficient miner selection and secure verification, enhancing performance and DDoS resistance in CRAHNs.

Future research should test the model in larger networks and integrate bioinspired consensus and Q-learning to improve performance and DDoS detection.

¹²⁰

The Hyperledger Fabric blockchain approach improves SDN DDoS mitigation by reducing response time and avoiding port blocking, enhancing security and flexibility.

The method uses Hyperledger Fabric to detect DDoS attacks with entropy analysis and maintain a victim IP blacklist on the blockchain, tested across various topologies and attack scenarios.

The main limitation is the high computational cost. Future work should optimize this, explore more attacks for IDS, test other blockchain platforms, and increase nodes for better performance.

Privacy-preserving solutions

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The BoLPP framework significantly improves security and privacy for secondary users in Cooperative Spectrum Sensing for 6G networks, showing better performance than existing methods.

The framework combines blockchain with Cognitive Radio Networks and uses energy detection, simulated in Python and MATLAB.

Drawbacks of using POW, low throughput.

Future directions include integration with additional technologies and analysis of new security threats.

¹²¹

The blockchain-based integrated security measure (BISM) enhances both access control and privacy for 6G communication, achieving improved security and service performance.

BISM uses blockchain for secure access and privacy, with Q-learning for decisions, and assesses performance with metrics like true positives and access success.

Future research should focus on testing BISM in practical 6G scenarios, optimizing its efficiency.

¹²²

The ACOMKSVM framework with ECC boosts IoT data privacy and security by using blockchain for secure data exchange and precise privacy protection.

The approach combines blockchain, ACOMKSVM, and ECC to secure and optimize IoT data sharing, tested on Breast Cancer Wisconsin and Heart Disease datasets.

Future work could extend the model to support various machine learning algorithms and improve privacy across multiple encrypted datasets.