Joint Crypto-Compression Based on Selective Encryption for WMSNs

Wireless Multimedia Sensor Networks (WMSNs) have been widely used in many aspects of life such as monitoring aims, risk environments and medical services. However, WMSNs have many challenges due to resources limitation (e.g., restriction in processing, energy and memory). Moreover, security issues related to WMSNs attract many research efforts. Due to limitations of WMSNs resources and their internal encoding, standard methods of data encryption are inappropriate to be used in order to secure data of WMSNs. In this paper, a compression algorithm named Set Partitioning In Hierarchical Tree (SPIHT), jointly with selective encryption during the compression process cycle, is proposed. Selected bins to be encrypted are analyzed and tested to preserve format compliance and constant bit rate. As a result the decoder will not crash. Moreover, any standard decoder can be used without any modifications. This is of great importance to the encoding companies that use standard Codecs. The proposed approach is suitable and capable to be used in WMSN taking into account their limitations of resources. The obtained results confirm the high performance of the proposed approach with an overhead of less than 1 %. The main contribution of this paper is the ability to use selective encryption based on tested and predefined bins that preserve format compliance and constant bit rate requirements during the compression cycle with minimum overhead. Thus, our proposed approach is applicable for real-time applications.