Efficient and Secure Visual Data Transmission Approach for Wireless Multimedia Sensor Networks Wireless Multimedia Sensor Networks (WMSNs) have to deal with two main opposite constraints: (a) the voluminous nature of the sensed data, almost of megabytes order on one hand and (b) the limited resources, characterizing specifically WMSNs platforms (limited energy provision and CPU power, wireless communications, etc.) on the other hand. Additionally, as these platforms are open infrastructures, they are hence vulnerable to several types of attacks. In this paper, we propose a new and novel approach, specifically tailored to significantly reduce the transmitted multimedia data whilst allowing a high level of security, in particular data confidentiality. In fact, rather than using traditionalcryptography systems which applied on multimedia data, inquiring a huge communication and hence overhead hence are not suitable within WMSNs, our approach begins first by transforming the input images using Voronoi tessellation, that reduces significantly their volume while preserving at the same time their perceived quality. As this transformation is performed on a random fashion basis, this randomness ensures then the content confidentiality. The proposed approach achieves hence both: (a) reducing noticeably the amount of the data sent by the source nodes, prolonging hence the overall network lifetime and (b) makes the network more robust against attacks. We study the parameters for setting up our approach by incorporating two schemes (basic one and more elaborated one). Finally, we demonstrate, through extensive experiments, the robustness (i.e., secure against several types of attacks) and the effectiveness of our approaches over the current state-of-the-art techniques.