The ever-developing 5G and Internet of Things (IoT) technology has recently drawn increased attention to the use and management of underutilized spectrum. Blockchain is a good potential solution, however, the Nakamoto consensus-based scheme has a low spectrum utilization rate, high transaction delay, and a huge waste of energy. In this paper, we present a novel decentralized distributed spectrum trading protocol STBC (Spectrum Trading Blockchain) base on blockchain, which explicitly aims for efficiency, simplicity, safety, and energy-saving. STBC uses a new consensus mechanism to quickly confirm transactions while tolerating up to ${n}$ /3 malicious nodes ( ${n}$ is the total number of nodes), and its implementation code is very concise. We adopt the similar idea of sharding to improve the efficiency and scalability of the system. Due to the specificality of spectrum trading, it is necessary to protect the privacy of trading nodes. Therefore we propose a temporarily anonymous transaction that can effectively prevent DDoS (Distributed Denial of Service) attack. Moreover, theoretical analysis shows that STBC is also secure against mainstream attacks such as double-spending attacks and the power consumption of STBC is significantly less than the Nakamoto consensus-based scheme. The prototype evaluation of our protocol demonstrates that it improves the spectrum utilization by about 30% compared with the state-of-the-art blockchain spectrum trading schemes, and meanwhile reducing the transaction confirmation delay by about 12.5x.

The exponential growth of data in the Internet of Vehicles (IoV) has created opportunities to improve traffic safety and efficiency through data trading. However, establishing trust among highly mobile and resource-constrained vehicles poses significant challenges for effective data trading in IoV. To address this issue, we propose a lightweight blockchain-based data trading scheme (LBDT), which ensures secure and efficient data trading in IoV. We introduce a proof-of-reputation (PoR) consensus mechanism to establish trustworthiness for data trading. Specifically, we use a progressive reputation mechainism to support the PoR consensus. LBDT utilizes a parallel-chain structure for the PoR consensus to minimize communication and storage costs while reducing transaction confirmation latency. Additionally, we adopt a double auction mechanism as an incentivizing strategy to encourage vehicle participation in data trading. We evaluate the performance of LBDT through extensive experiments. The experimental results demonstrate that LBDT is highly effective and secure, achieving a transaction latency of approximately 4 seconds. Moreover, LBDT successfully mitigates communication and storage overheads by over 90%, thus establishing its superiority over state-of-the-art solutions under comparable conditions.

Recently, many sharding blockchain protocols have sacrificed some important attributes to improve scalability, and this makes them complicated and insecure. Moreover, achieving a constant (rather than linear) Communication Cost Per Transaction (CCPT) is still a challenge for many sharding protocols. Motivated by this, we present EZchain, a scalable blockchain protocol via “passive sharding” with proven validity and security. We redesign the Value-Centric Blockchains (VCB) framework to achieve the passive sharding that helps EZchain reach higher security than traditional sharding protocols. With fixed initialization parameters, the expected value of EZchain's communication cost reaches a constant level, and it is independent of the network's size. Moreover, the EZchain node's storage cost without beacon chains also approaches a constant and does not change with the increase in the network's size and transactions. Cross-shard transactions, network sharding algorithm, and anti-Sybil attack verification are no longer needed in passive sharding, thus EZchain is very concise and efficient. Our experiment uses a lightweight EZchain prototype and extends the experimental network size up to 100,000 nodes. The evaluation results show that EZchain satisfies all our analyses of its performance (the constant communication and non-beacon storage cost) in large networks. In addition, the comparison experiment shows that ezchain has obvious advantages over the previous protocols in long-term operation and large network environments.

Blockchain technology has gained widespread use. However, it faces several challenges including throughput, transaction delay, security, and decentralization. This paper presents the Avalon protocol based on a novel Proof-of-Market (PoM) consensus mechanism to address these issues. PoM is a type of Proof-of-Work (PoW) consensus that incorporates market-driven leader election and shifts PoW from mining pools to consumers based on transactions. The matching incentive mechanism makes PoM incentive compatible. PoM decouples the scalability and security of Bitcoin, which means that Avalon can optimize the capacity and interval of blocks without compromising other performance goals. Our analysis shows that Avalon can tolerate malicious nodes possessing up to 1/3 of the network’s total computational power. Furthermore, the implementation of Avalon is similar to Bitcoin and is highly concise. We evaluate the performance of Avalon through a simulated network of over 1,000 nodes. Experimental results demonstrate that Avalon can achieve a throughput of 4,000 TPS (transactions per second), which is significantly better than state-of-the-art schemes (10× Bitcoin-NG, 5× ByzCoin, and 4× Algorand). Additionally, it has a transaction confirmation delay of up to 40 s, which is twice better than Bitcoin-NG and ByzCoin while experiencing only minimal blockchain splits and maintaining excellent decentralization.

Blockchain faces significant challenges in scalability, user practicality, and regulatory compliance, especially as on-chain data grows. Stateless blockchains (SBCs) reduce node storage by moving state off-chain, but introduce critical issues: they require frequent witness updates that force users to remain online, and prevent regulatory nodes from independently verifying transaction histories. To address these limitations, we propose BMchain, an end-to-end SBC that innovates in data structure and collaboration model. BMchain maintains a lightweight main chain (under 2 MB per block) by recording only Bloom filters and Merkle roots of transactions. This design allows users to transact without being constantly online and enables regulators to verify data completeness and correctness solely from on-chain information. Experimental results show BMchain achieves over 10 000 TPS throughput, reduces annual account storage to around 200 MB, and confirms transactions within 2 min at scale—significantly outperforming existing solutions. Unlike accumulator-based approaches, BMchain fundamentally decouples local state updates from global ledger changes, offering a practical and regulatory-friendly SBC architecture.