Robust encryption method based on AES-CBC using elliptic curves Diffie–Hellman to secure data in wireless sensor networks

Secure data is a foremost topic in wireless sensor networks since data are transmitted through wireless channels where attackers may get access to critical information. Addressing critical resource-constrained devices of WSN, existing solutions do not consider the specific constraints of WSN in terms of limited resources. We propose a robust encryption based on AES encryption method in CBC mode using Elliptic Curves Diffie-Hellman key exchange to ensure data integrity and confidentiality in WSN. For this, we propose to use an Elliptic curve 25,519 (RFC 7748) to generate g(x, y) in order to compute a shared secret SK(X, Y) where X' is the initialization vector corresponding to the last 128 bits of X and Y is the initial 256-bits AES key. This approach is robust and scalable, contrary to the mapping technique, which consists in transforming the plaintext into a sequence of points on the elliptic curve before performing the arithmetic operations to obtain the cipher. We performed several tests to evaluate the performance of the proposed encryption method in order to compare it to existing review. For performance analysis, the running time of the cryptographic processes, the memory occupation rate, the energy consumption are computed in order to show the best results with regard to robustness and ability to adapt to the constraints of sensor networks.