A Blockchain-Based Decentralized Review System for Secure and Tamper-Proof Feedback

Abstract

The proposed Decentralized Review Systemisdesignedtorevolutionizethewayproduct and service reviews are created, stored, and verified. In contrast to conventional centralized review platforms, where content can be altered or removed,thissystemusesblockchaintechnologyto store the cryptographic hashes of review data, thereby guaranteeing immutability, transparency, and long-term availability. Each review is permanently tied to the identity of its author throughasecureauthenticationprocess.Toensure the confidentiality, integrity, and authenticity of thereviews,thesystememploysHMACandSHA-256cryptographictechniques,whichgenerateunique digital signatures and proofs for every submission. This decentralized architecture minimizestheriskoffakeormanipulatedreviews, enhances trust between customers and service providers, and creates an auditable, tamper- resistantledgeroffeedback.Bycombiningidentity verification with immutable record-keeping, the systemoffersarobustandtrustworthymechanism for consumer insights without dependence on a single controlling authority.

Introduction

The paper proposes a decentralized blockchain-based review system to solve key problems in traditional online review platforms, such as fake reviews, data manipulation, lack of transparency, and weak user trust. Centralized systems are vulnerable to unauthorized edits and poor audit trails, which reduce credibility.

To address these issues, the study uses a permissioned blockchain (Hyperledger Fabric) combined with off-chain storage (e.g., IPFS). Only cryptographic hashes, HMAC values, and user identifiers are stored on-chain, while full review text is kept off-chain. This ensures both data integrity and efficiency without overloading the blockchain.

The system uses SHA-256 hashing and HMAC authentication to verify review authenticity and prevent tampering or impersonation. Smart contracts automate key functions such as access control, timestamping, moderation rules, and dispute handling. This creates a transparent and tamper-proof audit trail for all reviews.

The literature review shows a shift from centralized review systems to blockchain-based solutions, with Hyperledger Fabric emerging as a preferred platform due to its scalability, privacy control, and permissioned access. Prior studies highlight its effectiveness in preventing fake reviews and improving accountability.

The methodology involves a hybrid architecture where reviews are submitted through a web interface, hashed, authenticated, and stored on-chain, while the actual content is stored off-chain. Verification is done by recomputing hashes and HMAC values to detect any tampering.

Experimentally, the system successfully generates secure hashes and stores immutable records on the blockchain. It reduces storage costs, improves scalability, and ensures privacy while maintaining strong security guarantees. Overall, the system demonstrates a reliable, efficient, and trustworthy framework for decentralized review management that enhances user confidence and prevents manipulation.

Conclusion

The proposed Decentralized Review System successfully demonstrates how blockchain technology combined with cryptographic mechanisms such as SHA-256 and HMAC can transform the way online reviews are managed. By immutably storing only review hashes, HMAC values, and user identifiers on theblockchainwhilekeepingtheactualreviewtextoff- chain, the system achieves a balance between security, decentralization, and efficiency. This hybrid architecture ensures authenticity, integrity, and transparency of user feedback, while protecting reviewer privacy and reducing on-chain storage costs. Through the implemented interface, users can securely submit reviews, track real-time transaction status, and verify authenticity without relying on a centralized authority.Theuseofsmartcontractsfortime-stamping, access control, and dispute resolution further strengthens the trustworthiness of the platform. Compared to traditional review systems, this decentralized approach minimizes the risks of tampering, impersonation, and unauthorized modifications, thereby enhancing user confidence and decision-making. In essence, the Decentralized Review System lays the groundwork for a scalable and privacy-preserving review ecosystem that can be extended toe-commerce, healthcare, supply chain, and other domains where feedbackauthenticityiscritical.Bygivingusers ownership over their reviews and providing cryptographicproofsofvalidity,thesystemrepresentsa significant step toward a more transparent, secure, and trustworthy online review environment.

References

The proposed Decentralized Review System successfully demonstrates how blockchain technology combined with cryptographic mechanisms such as SHA-256 and HMAC can transform the way online reviews are managed. By immutably storing only review hashes, HMAC values, and user identifiers on theblockchainwhilekeepingtheactualreviewtextoff- chain, the system achieves a balance between security, decentralization, and efficiency. This hybrid architecture ensures authenticity, integrity, and transparency of user feedback, while protecting reviewer privacy and reducing on-chain storage costs. Through the implemented interface, users can securely submit reviews, track real-time transaction status, and verify authenticity without relying on a centralized authority.Theuseofsmartcontractsfortime-stamping, access control, and dispute resolution further strengthens the trustworthiness of the platform. Compared to traditional review systems, this decentralized approach minimizes the risks of tampering, impersonation, and unauthorized modifications, thereby enhancing user confidence and decision-making. In essence, the Decentralized Review System lays the groundwork for a scalable and privacy-preserving review ecosystem that can be extended toe-commerce, healthcare, supply chain, and other domains where feedbackauthenticityiscritical.Bygivingusers ownership over their reviews and providing cryptographicproofsofvalidity,thesystemrepresentsa significant step toward a more transparent, secure, and trustworthy online review environment.

Copyright

Copyright © 2026 Harsh Singh, Ritik Singh, Ankit Tiwari. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.