Advancing Cryptography at Zama: Highlights from ASIACRYPT 2025

Recent research at Zama resulted in three significant papers presented at ASIACRYPT 2025, focusing on advancements in cryptographic techniques and fully homomorphic encryption (FHE). The first paper introduces anamorphic signatures, which enable covert communication within digital signatures, ensuring privacy even in environments that ban encryption, by embedding undetectable messages that maintain both dictator and recipient unforgeability. The second paper addresses the efficiency of bootstrapping in fully homomorphic encryption, introducing a new primitive that merges multiple operations into a single, more efficient one, thereby reducing computation time and noise growth and offering improved blind rotation algorithms with flexible trade-offs. The third paper proposes Sorted Bootstrapping (SBS) for TFHE, which optimizes the bootstrapping process by identifying and eliminating unnecessary external products during blind rotation, resulting in significant performance gains and speedups compared to traditional and EBS-based bootstrapping methods, supported by extensive benchmarks and experimental results.