This chapter is devoted to providing anonymous group writing. Our solution involves constructing an approximately random sequence as noise by overlapping transmission data from different tag groups, thereby hiding the original information with low computational complexity. In this context, we propose an Overlapped Bloom Filter (OBF), a compact filter that guarantees time efficiency while improving the security of the group writing. To ensure tags can verify the correctness of decoded group data, the enhanced version, OBF+, introduces the complementary code-based check mechanism to eliminate faulty data.