Secure data transmission is a critical issue for wireless sensor networks. Clustering is an effective and practical way to enhance the system performance of WSNs. A secure data transmission for cluster-based WSNs is studied, where the clusters are formed dynamically and periodically. User propose two Secure and Efficient data Transmission protocols for CWSNs, called SET-IBS and SET-IBOOS, by using the Identity-Based digital Signature scheme and the Identity-Based Online/Offline digital Signature scheme, respectively. In SET-IBS, security relies on the hardness of the Hellman problem in the pairing domain. SET-IBOOS further reduces the computational overhead for protocol security, which is crucial for WSNs, while its security relies on the hardness of the discrete logarithm problem. We show the feasibility of the SET-IBS and SET-IBOOS protocols with respect to the security requirements and security analysis against various attacks. The calculations and simulations are provided to illustrate the efficiency of the proposed protocols. The results show that, the proposed protocols have better performance than the existing secure protocols for CWSNs, in terms of security overhead and energy consumption.