Omni-digital reconfigurable intelligent surfaces (Omni-DRIS) has been proposed to enhance the coverage of visible light communication (VLC) systems in recent years. Compared with traditional optical RIS using only reflections, Omni-DRIS is capable of extending the communication range of VLC even further, using both refection and refraction. Although RIS VLC system’s security performance inside one room has been studied in the literature, the security communication data rate is not directly applicable to Omni-DRIS systems, which cover two rooms simultaneously, using bi-directions transmissions. In this paper, we focus on the system where two rooms are interconnected using one Omni-DRIS in the middle. Alice node’s information is transmitted using both signal light emitting diodes (LEDs) and noise LEDs on the ceilings. The Eve node can appear in any room to eavesdropping Bob users. However, we argue that the minimum-secrecy-rate maximization problem in the Omni-DRIS setting is non-deterministic polynomial-time (NP) hard. To solve the optimization problem, we first make use of an alternating optimization (AO) algorithm to transform the original problem into two sub-problems, and then we adopt the successive convex approximation (SCA) method to solve the sub-problems. Simulation results show that, when the number of user is 2 and the LED transmitting power is 25 dBm, the minimum secrecy rate of the Omni-DRIS system is approximately 105% and 1425% larger compared with state-of-the-art RIS-VLC and non-precoding benchmark systems, respectively. In addition, we find that increasing the number of Omni-DRIS elements can significantly enhance the security performance. Our findings have important implications for the large-scale deployment of secured Omni-DRIS enhanced VLC systems in the future.