In this paper, we proposed two algorithms (Reverse and Block) to conduct online monitoring against a safety LTL specification via fully homomorphic encryption. We implemented these two algorithms in C++20 and experimentally answered two research questions (RQ1 and RQ2) we posed. This artifact includes a Docker image including our C++20 programs and some scripts for the experiments to replicate our experimental results shown in the paper. It measures execution runtimes to generate monitored ciphertexts, execute our proposed algorithms using the inputs, and decrypt the result. It also has a functionality named plaintext mode, and one can check if the decrypted result is the same as the one executed in plaintext. We note that the runtimes we presented in the paper were obtained on a workstation, and they will differ from the ones on a laptop. In this artifact, we also show the runtimes obtained on our laptop for reference. System requirements to execute this artifact are as follows: CPU: 2 cores and 4 threads or more. It must support AVX2 and AES-NI, i.e., it must be Intel Core i 5000 series or newer, or AMD Ryzen 1000 series or newer. RAM: 4GiB or more Disk: 10GiB or more of free space Misc: Docker must be installed. sha256sum: c9ab9c722b646f1fbc5c79f158bc1a8c1ddf303b324196ee0a83135c0dac401e NOTE: Although our software is licensed under Apache-2.0, the library Spot is licensed under GPL v3, and the Docker image in this artifact includes its binary. Thus, in our understanding, we need to distribute this artifact under GPL v3. We noticed it after we made this artifact, so the LICENSE file in this artifact is Apache-2.0, which is wrong.