The increasing popularity of distributed and collaborative applications prompts the need for secure communication in collaborative groups. Some distributed collaborative key management protocols have been proposed to provide group communication privacy and data confidentiality for collaborative groups. However, most of them rekey on each member change, and the costs of group rekeying can be quite substantial for large groups with frequent membership changes. In this paper, we propose a scalable distributed key management scheme using a distributed one-way function tree named SIKAS which can significantly reduce the computation and communication costs of maintaining the group key based upon period-based group rekeying. A comparison with previous work has shown that SIKAS provides scalability and rekeying efficiency while preserving both distributed and collaborative properties.