implementing-homomorphic-encryption
Installation
SKILL.md
Implementing Homomorphic Encryption
Overview
Homomorphic encryption (HE) enables computation on encrypted data without decryption. The data owner encrypts their data, sends the ciphertext to a computing party (e.g., a cloud processor under Article 28), and the computing party performs operations on the ciphertext. The encrypted results are returned to the data owner, who decrypts them to obtain the plaintext result. At no point does the computing party see unencrypted data.
This directly supports GDPR Article 32(1)(a), which identifies encryption as an appropriate technical measure, and Article 25(1), which requires data protection by design. HE enables a controller to outsource computation to a processor while maintaining cryptographic confidentiality of personal data.
HE Scheme Selection
Scheme Comparison
| Scheme | Arithmetic Type | Exact/Approximate | Operations | Best For | Libraries |
|---|---|---|---|---|---|
| BFV | Integer (modular) | Exact | Add, Multiply (limited depth) | Counting, matching, exact integer computation | Microsoft SEAL, OpenFHE |
| BGV | Integer (modular) | Exact | Add, Multiply (with modulus switching) | Deep circuits on integers, batched operations | HELib, OpenFHE |
| CKKS | Real/Complex | Approximate | Add, Multiply, Rotation | ML inference, statistical analysis, floating-point computation | Microsoft SEAL, OpenFHE, HEAAN |
| TFHE | Boolean/Integer | Exact | Arbitrary (gate-by-gate) | Programmable bootstrapping, arbitrary functions | TFHE-rs, Concrete (Zama) |