Existing communication infrastructures may be unavailable in the aftermath of a disaster. Under these circumstances, it is difficult to share information, such as text, image, and audio data, in the areas where the communication infrastructure is unavailable. Since these contents are usually composed of multiple packets, existing communication methods cannot be applied to share them. To enable information sharing without using the existing communication infrastructure in these areas, we have proposed a novel system “Broadcast-Based Information Sharing System (BBISS)”. The paper evaluates the performance of BBISS using network simulations. It can be concluded from the simulation results that the proposed method achieves high information reachability without significantly increasing the number of packet exchanges. Also, we optimize the parameters for BBISS.