Preserving Privacy with Homomorphic Encryption and Comparison Operation in Decentralized Identity

Abstract

Blockchains raise new privacy challenges, especially in Decentralized Identity (DI) and Self-Sovereign Identity (SSI) systems. Zero Knowledge Proofs (ZKPs) offer privacy, but only allow binary verification. Homomorphic Encryption (HE) enables flexible operations on encrypted data (e.g., addition, multiplication) but lacks comparison support. This paper addresses this gap by introducing a privacy-preserving comparison operation within HE, presenting the first comprehensive comparison of ZKP and HE as privacy-preserving mechanisms.