<p>The distributed randomness beacon (DRB) is a crucial tool for continuously generating unpredictable, bias-resistant, and publicly verifiable random numbers on a regular basis. This is particularly useful for applications such as lotteries, electronic voting, and cryptographic parameter generation. However, existing studies either require complex communication or rely on a public bulletin board to meet security requirements. This brings a performance bottleneck when dealing with a large number of participants. This paper introduces a novel DRB protocol PltcRB based on timed commitments, eliminating the need for a public bulletin board. Our approach achieves optimal communication complexity of <i>O</i>(<i>n</i>) while maintaining the desired properties of a DRB protocol. The computation complexity is also <i>O</i>(<i>n</i>) when <i>n</i> is larger than the security parameter <i>κ</i>. These results demonstrate the practicality and performance of PltcRB, supported by our experimental analysis under various configurations.</p>