Electric Vehicles (EVs) are becoming more and more popular in our daily life, which replaces traditional fuel vehicles to reduce carbon emissions and protect the environment. EVs need to be charged, but the number of charging piles in a Charging Station (CS) is limited and charging is usually more time-consuming than fueling. According to this scenario, we propose a secure and efficient charging scheduling system based on a Directed Acyclic Graph (DAG)-blockchain and double auction mechanism. In a smart area, it attempts to assign EVs to the available CSs in the light of their submitted charging requests and status information. First, we design a lightweight charging scheduling framework that integrates DAG-blockchain and modern cryptography technology to ensure security and scalability during performing scheduling and completing tradings. In this process, a constrained multi-item double auction problem is formulated because of the limited charging resources in a CS, which motivates EVs and CSs in this area to participate in the market based on their preferences and statuses. Due to this constraint, our problem is more complicated and harder to achieve truthfulness as well as system efficiency compared to the existing double auction model. To adapt to it, we propose two algorithms, namely Truthful Mechanism for Charging (TMC) and Efficient Mechanism for Charging (EMC), to determine an assignment between EVs and CSs and pricing strategies. Then, both theoretical analysis and numerical simulations show the correctness and effectiveness of our proposed algorithms.

翻译：电动汽车（EV）正日益普及，逐步取代传统燃油汽车，以减少碳排放并保护环境。电动汽车需要充电，但充电站（CS）的充电桩数量有限，且充电通常比加油更耗时。针对这一场景，我们提出了一种基于有向无环图（DAG）区块链和双向拍卖机制的安全高效的充电调度系统。在智能区域内，该系统根据提交的充电请求和状态信息，尝试将电动汽车分配至可用的充电站。首先，我们设计了一个轻量级充电调度框架，该框架集成了DAG区块链和现代密码学技术，以确保调度执行和交易完成过程中的安全性与可扩展性。在此过程中，由于充电站充电资源受限，我们构造了一个带约束的多物品双向拍卖问题，促使该区域的电动汽车和充电站基于各自偏好与状态参与市场。与现有双向拍卖模型相比，该约束使我们的问题更复杂，更难实现真实性及系统效率。为适应这一情况，我们提出了两种算法——充电真实机制（TMC）和充电高效机制（EMC），以确定电动汽车与充电站之间的分配及定价策略。理论分析与数值仿真均表明了所提算法的正确性和有效性。