MATCHA: A Fast and Energy-Efficient Accelerator for Fully Homomorphic Encryption over the Torus
This addresses the performance bottleneck for secure computation in privacy-sensitive applications, representing a strong incremental advance in accelerator design.
The paper tackles the slow and energy-inefficient processing of Fully Homomorphic Encryption over the Torus (TFHE) gates on existing hardware, achieving a 2.3x improvement in throughput and a 6.3x increase in throughput per Watt with the proposed MATCHA accelerator.
Fully Homomorphic Encryption over the Torus (TFHE) allows arbitrary computations to happen directly on ciphertexts using homomorphic logic gates. However, each TFHE gate on state-of-the-art hardware platforms such as GPUs and FPGAs is extremely slow ($>0.2ms$). Moreover, even the latest FPGA-based TFHE accelerator cannot achieve high energy efficiency, since it frequently invokes expensive double-precision floating point FFT and IFFT kernels. In this paper, we propose a fast and energy-efficient accelerator, MATCHA, to process TFHE gates. MATCHA supports aggressive bootstrapping key unrolling to accelerate TFHE gates without decryption errors by approximate multiplication-less integer FFTs and IFFTs, and a pipelined datapath. Compared to prior accelerators, MATCHA improves the TFHE gate processing throughput by $2.3\times$, and the throughput per Watt by $6.3\times$.