This paper presents \textit{OFHE}, an electro-optical accelerator designed to process Discretized TFHE (DTFHE) operations, which encrypt multi-bit messages and support homomorphic multiplications, lookup table operations and full-domain functional bootstrappings. While DTFHE is more efficient and versatile than other fully homomorphic encryption schemes, it requires 32-, 64-, and 128-bit polynomial multiplications, which can be time-consuming. Existing TFHE accelerators are not easily upgradable to support DTFHE operations due to limited datapaths, a lack of datapath bit-width reconfigurability, and power inefficiencies when processing FFT and inverse FFT (IFFT) kernels. Compared to prior TFHE accelerators, OFHE addresses these challenges by improving the DTFHE operation latency by 8.7\%, the DTFHE operation throughput by $57\%$, and the DTFHE operation throughput per Watt by $94\%$.

翻译：本文提出了一种名为OFHE的光电加速器，专为处理离散化TFHE（DTFHE）运算而设计。DTFHE可加密多比特消息，并支持同态乘法、查找表运算及全域函数性自举。尽管DTFHE相较于其他全同态加密方案更为高效且通用，但它需要执行32位、64位及128位多项式乘法，这可能导致计算耗时。现有TFHE加速器因数据路径受限、缺乏位宽可重构性以及在处理FFT与IFFT核时能效低下，难以升级以支持DTFHE运算。与先前的TFHE加速器相比，OFHE通过将DTFHE运算延迟降低8.7%、吞吐量提升57%、每瓦吞吐量提升94%，有效解决了上述挑战。