AUKA: Asynchronous updatable key agreement for edge-based mobile crowd sensing

Edge-based mobile crowd sensing (E-MCS) enhances efficiency by leveraging edge servers for local task processing, reducing cloud load and latency. However, establishing secure, low-latency communication between mobile devices and edge servers remains a challenge. Existing key agreement (KA) schemes either require multiple interaction rounds, increasing latency and energy consumption, or compromise security properties like perfect forward security and key-compromise impersonation resistance. To address these limitations, we propose an asynchronous updatable KA (AUKA) scheme tailored for E-MCS. AUKA is built upon key agreement, incorporating the design concept of updatable key encryption and leveraging standard cryptographic primitives such as hash functions to construct an efficient scheme with a session key update mechanism. AUKA achieves strong perfect forward security, even if a mobile device's private key and random number are compromised, all previously established session keys remain secure, effectively mitigating long-term security risks. Additionally, AUKA maintains an almost 0-RTT property, enabling efficient session key establishment and key updates without introducing excessive communication overhead. We prove its security under the gap computational Diffie–Hellman assumption and validate its efficiency through simulations. Results demonstrate that AUKA offers a highly secure and scalable solution for E-MCS.