Hermes: MySQL Plugin for Homomorphic Encryption

Hermes stands for Homomorphic Encryption for Relational MySQL Engine Support.
The system embeds homomorphic encryption directly into MySQL via native UDF plugins, enabling SQL users to perform secure computation on encrypted data without modifying their queries.

The name is also inspired by Hermes, the Greek god of communication, reflecting the system's goal of secure, efficient, and seamless delivery of encrypted information.

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🧠 Academic Background

Hermes is part of an academic research initiative at the University of Washington, aiming to bridge modern cryptography and database systems. It is the first system to integrate fully homomorphic encryption (FHE) directly into a production-grade SQL engine, supporting vectorized queries with provable security guarantees.

The system and its contributions are formally described in the following research paper:

Hermes: Practical Vectorized Query Processing over Homomorphically Encrypted Relational Databases
Dongfang Zhao
https://arxiv.org/abs/2506.03308

Please cite the paper if you use Hermes in academic publications.

🔐 Key Features

Hermes exposes the following homomorphic encryption UDFs as native SQL functions. Each UDF is implemented in a corresponding .so plugin module:

UDF Function	Description	Source File
HERMES_ENC_SINGULAR_BFV(val)	Encrypt scalar integer (slot[0])	singular/udf.cpp
HERMES_DEC_SINGULAR_BFV(ct)	Decrypt scalar ciphertext	singular/udf.cpp
HERMES_SUM_BFV(ct)	Aggregate ciphertexts homomorphically	singular/udf.cpp
HERMES_MUL_BFV(ct1, ct2)	Multiply two ciphertexts	singular/udf.cpp
HERMES_PACK_CONVERT(val)	Pack group values into vector ciphertext	pack/packing.cpp
HERMES_DEC_VECTOR(ct)	Decrypt packed vector into CSV	pack/packing.cpp
HERMES_PACK_GROUP_SUM(val)	Encrypt per-group sum	pack/packsum.cpp
HERMES_PACK_GLOBAL_SUM(ct)	Add all group ciphertexts	pack/packsum.cpp
HERMES_ENC_SINGULAR(val)	Encrypt scalar as BFV (internal SO-safe)	pack/packsum.cpp
HERMES_DEC_SINGULAR(ct)	Decrypt scalar (internal SO-safe)	pack/packsum.cpp
HERMES_PACK_ADD(ct, val, idx)	Insert value at given slot in packed ciphertext	pack/packupdate.cpp
HERMES_PACK_RMV(ct, idx, k)	Remove slot at index, compact vector	pack/packupdate.cpp
HERMES_SUM_CIPHERS(ct1, ct2)	EvalAdd of two ciphertexts	pack/packupdate.cpp

All functions use the BFV scheme via OpenFHE and are compatible with standard SQL operators such as SELECT, GROUP BY, and CAST.

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🚀 Quick Start

Build and test with:

./script/build.sh               # Compile and register plugins
./script/run_crypto.sh          # Run primitive FHE operations
./script/run_singular.sh        # Run single-tuple demo
./script/run_pack.sh            # Run packed vector + summation demo

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🧪 Reproducible Experiments

To run the benchmark suite:

./experiments/script/load_csv.sh        # Load data into MySQL
./experiments/script/convert_csv.sh     # Preprocess and assign group IDs
./experiments/script/run_all.sh         # Evaluate encryption, insert, delete

This will produce results in ./experiments/result/*.txt, covering all three datasets: covid19, bitcoin, and hg38.

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📦 Design Philosophy

Hermes is designed to:

• Minimize system intrusion: implemented entirely as MySQL loadable functions with C++.
• Enable modular deployment: each homomorphic operation is a plugin.
• Preserve SQL compatibility: no schema rewrites or query rewriting.
• Support secure processing: all ciphertexts remain encrypted in transit and storage.

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📬 Contact

(c) 2025, HPDIC Lab, https://hpdic.github.io
Author: Dongfang Zhao
📧 Email: dongfang.zhao@gmail.com

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📄 License

This project is released under the Apache License 2.0.