"Code of accelerating NTRU based bootstrapping for MKFHE-we"

"Multi-key fully homomorphic encryption enables arbitrary computations on ciphertextsencrypted under different secret keys, thereby ensuring data privacy in multi-party scenarios. Recently, Xianget al. (ASIACRYPT 2024) proposed a new NTRU-based bootstrapping algorithm and a more lightweight keyswitching algorithm, yielding an efficient MKFHE scheme. In this work, we design a new CMux gate usingkey unrolling algorithm, which makes the bootstrapping algorithm more efficient.Despite the evaluationkey size increasing slightly from 15.831 MB to 15.915 MB, the number of multiplications required forperforming bootstrapping over the ring RQ is theoretically reduced by half. Meanwhile, the noise growthremains within Oe(kn1.5 ). Experimental results demonstrate that the runtime of our scheme achieves a slightspeedup (e.g., 1.67% for 8 keys) compared to the original work."