Bootstrapping TFHE ciphertexts in less than one millisecond

Zama has achieved a significant milestone in Fully Homomorphic Encryption (FHE) by reducing the latency of TFHE bootstrapping to microseconds using GPUs, while maintaining the same security level and probability of failure for 4-bit messages. This advancement is crucial for performing efficient operations on encrypted data, as bootstrapping has been a major performance bottleneck. The journey to this achievement began with a CPU implementation that took 53 ms and has culminated in GPU acceleration that reduces the time to approximately 800 microseconds. This was made possible through the use of a multi-bit algorithm that offers more parallelism, alongside numerous optimizations that enhance GPU performance. The current implementation balances latency and throughput, facilitating faster high-level operations like addition and multiplication of 64-bit encrypted messages. With this progress, the FHE performance is approaching that of cleartext computation, potentially revolutionizing its application in fields like blockchain, despite other bottlenecks such as network communication and zero-knowledge proofs.