Secure Survey System using FHE

In the age of rapid quantum computing development, quantum computers pose a serious threat to traditional encryption methods such as the Rivest-Shamir-Adleman (RSA) cryptosystem. Fully Homomorphic Encryption (FHE) emerges as an ideal candidate for Post-Quantum Cryptography, as no quantum algorithm has yet been devised to break it. Moreover, FHE allows entities to perform computations on data without the need to decrypt it. Threshold FHE(2) further enhances FHE by distributing the decryption key among multiple parties, ensuring that no single entity can decrypt the data alone, thereby decentralizing data security. To showcase the value of adopting FHE as a standard in industries such as healthcare and government, we developed a client-server survey protocol based on FHE. Each user receives a partial key to encrypt their responses in our protocol. These individual encrypted responses are sent to a central server, which aggregates the responses and analyzes them while preserving individual client privacy. For instance, the server can determine that 50% of participants voted "yes" without identifying individual votes. We utilized the OpenFHE library and employed the Brakerski/Fan-Vercauteren (BFV) scheme, which supports finite field arithmetic for our implementation. This work emphasizes the importance of FHE in building modern cryptosystems that are safe from attacks from quantum-capable adversaries.

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2. Boura, C., Giacomelli, I., Iliashenko, I., & Savas, E. (2022). OpenFHE: Open-Source Fully Homomorphic Encryption Library. Cryptology ePrint Archive, Paper 2022/1625. https://eprint.iacr.org/2022/1625.pdf