CHLOE: Loop Transformation over Fully Homomorphic Encryption via Multi-Level Vectorization and Control-Path Reduction
Song Bian, Zian Zhao, Ruiyu Shen, Zhou Zhang, Ran Mao, Dawei Li
IEEE Symposium on Security and Privacy 2025 · Day 2 · Secure Data Processing I
The talk introduces CHLOE, an innovative compiler designed to significantly enhance the efficiency of programs leveraging Fully Homomorphic Encryption (FHE) by addressing one of FHE's most challenging computational bottlenecks: loops. Fully Homomorphic Encryption is a groundbreaking cryptographic primitive that allows computations to be performed directly on encrypted data without ever decrypting it, thus preserving data privacy even when processed by untrusted third parties, such as cloud providers. However, the inherent complexity of FHE operations often leads to substantial performance overhead, making its practical adoption difficult for real-world applications. CHLOE focuses on mitigating this overhead, particularly for programs containing complex loop structures and conditional branches, which are notoriously inefficient in the FHE paradigm.