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Implementation of A Blockchain-based Searchable Encryption for Securing Contact Tracing Data

Zheng Yao Ng,
Iftekhar Salam,


We developed a blockchain-based multi-keyword searchable encryption scheme for securing COVID-19 contact tracing data. In this scheme, we used AES-GCM to encrypt the contact tracing data, guaranteeing that only authorized users can perform decryption. Our scheme employed a Ciphertext-Policy Attribute-based searchable encryption to encrypt the search index, ensuring only users with appropriate attributes can perform search operations. The scheme supports dynamic updates of the search index. The blockchain-based storage with smart contract ensures immutability and non-repudiation of storage and retrieval. Overall, the evaluation of the scheme shows that it works efficiently without compromising the security goals. This is one of the first works to implement a solution for secure storage and search of contact tracing data with blockchain-based searchable encryption. Compared to the existing searchable contact tracing schemes, it provides more features and maintains efficiency even if a large search index is used.


Contact tracing, Attribute-based searchable encryption, Blockchain, Smart contract, Privacy preserving encryption

Citation Format:
Zheng Yao Ng, Iftekhar Salam, "Implementation of A Blockchain-based Searchable Encryption for Securing Contact Tracing Data," Journal of Internet Technology, vol. 25, no. 2 , pp. 241-254, Mar. 2024.

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