  In recent years, the blockchain-based Internet of Things (IoT) has been
researched and applied widely, where each IoT device can act as a node in the
blockchain. However, these lightweight nodes usually do not have enough
computing power to complete the consensus or other computing-required tasks.
Edge computing network gives a platform to provide computing power to IoT
devices. A fundamental problem is how to allocate limited edge servers to IoT
devices in a highly untrustworthy environment. In a fair competition
environment, the allocation mechanism should be online, truthful, and privacy
safe. To address these three challenges, we propose an online multi-item double
auction (MIDA) mechanism, where IoT devices are buyers and edge servers are
sellers. In order to achieve the truthfulness, the participants' private
information is at risk of being exposed by inference attack, which may lead to
malicious manipulation of the market by adversaries. Then, we improve our MIDA
mechanism based on differential privacy to protect sensitive information from
being leaked. It interferes with the auction results slightly but guarantees
privacy protection with high confidence. Besides, we upgrade our
privacy-preserving MIDA mechanism such that adapting to more complex and
realistic scenarios. In the end, the effectiveness and correctness of
algorithms are evaluated and verified by theoretical analysis and numerical
simulations.
