In the past few years trustworthy transmission of data along with efficiency is a critical issue for wireless sensor networks (WSNs). Clustering is an effectual and convenient way to enhance performance of the WSNs system. This thesis presents a secure transmission of data for cluster-based WSNs (CWSNs), where the clusters are formed dynamically and sporadically. By making use of two Efficient and Trustworthy data Transmission (ETT) protocols for CWSNs, called ETT-IBS and ETT-IBOOS, by means of the Identity-Based digital Signature (IBS) scheme and the Identity-Based Online/Offline digital Signature (IBOOS) scheme, correspondingly. In ETT-IBS, security relies on the hardness of the Diffie-Hellman problem in the pairing area. ETT-IBOOS additionally decreases the computational operating cost for protocol security, which is critical for WSNs, while its defence depends on the stability of the problem of discrete logarithm.