面向医疗区块链的新型轻节点数据查询方法

医疗区块链系统的用户向全节点请求数据时可能被欺骗，而简单支付验证等轻节点数据查询方法面临着存储困难。为解决这些问题，提出了一种面向医疗区块链的新型轻节点数据查询方法。引入具有动态追加能力的Merkle山脉（Merkle mountain range,MMR），设计基于推荐的可信节点选择和基于采样的可信节点验证的最新有效块获取算法，采取MMR和Merkle树的承诺机制，使得持有一个最新有效块的轻节点用户能够验证全节点发送的医疗数据。此外，还将该方法扩展应用于联盟链。分析和实验表明，所提方法的时间开销和空间开销均在较低的范围内。

New Light Node Data Query Method for Medical Blockchains

In medical blockchain systems, users may be cheated by whole node when they request data from the whole node. Meanwhile, owing to the lack of storage, simple payment verification (SPV) and other verification methods of light node data are not applicable to medical blockchain systems. In order to solve these problems, this paper proposes a new light node data query method for medical blockchains. In the proposed method, the Merkle mountain range (MMR) with dynamic addition capability is introduced, and the latest valid block query algorithm based on recommendation trusted node selection and trusted node verification on sampling is designed. Accordingly, by using the commitment mechanism of the MMR and Merkle tree, the medical data sent by the whole node are verified by the user of the light node which holds the latest valid block obtained from a trusted node. Furthermore, the proposed method can be extended to the application of consortium blockchains. Analysis and experiments on the proposed method show that both time cost and space cost are in low overhead ranges.