Enhancing Data Confidentiality in Wireless Sensor Networks Using Hybrid Encryption and Dynamic Key Management

Abstract

Distributed Denial of Service (DDoS) attacks and unauthorized data accesses are some of the major problems encountered in Wireless Sensor Networks (WSNs) primarily due to the limitations in computation and energy of the sensor nodes. Typical single-algorithm cryptographic solutions fail to meet security strength versus processing efficiency requirements in some such environments. We introduce, in this paper, a lightweight hybrid encryption framework based on the Advanced Encryption Standard (AES) and Blowfish algorithms for the session key management purpose, using the HMAC-based Key Derivation Function (HKDF). AES in Counter (CTR) mode is used to encrypt the main data layer quickly, while the Blowfish secondary fast encryption layer provides greater security against brute force and cryptanalytical attacks. HKDF generates a new session key for every phase of encryption, avoiding the risk of replay and man in the middle attacks and preventing key reuse. Unlike conventional hybrid encryption schemes, the proposed framework activates dual-layer encryption only after malicious traffic is detected, thereby minimizing unnecessary computational overhead while strengthening data confidentiality. Our experiments demonstrate that the proposed model provides the encryption time of 0.015 s, the entropy of 8.2 bits, the throughput of 5500 bits/s, and the latency of 0.10 ms which are better than the standalone implementations of AES, Blowfish and RSA. The results indicate that the proposed framework is able to satisfy the desired level of security of WSNs and keep the computing resources low to enable the system to be deployed in real time.