Data authorization method and system based on block chain

The invention relates to the technical field of block chains, in particular to a data authorization method and system based on a block chain. The method comprises the steps that a node in the block chain receives a data acquisition request, and analyzes the data acquisition request to obtain an authorization range of a requester sending the data acquisition request; if the authorization range of the requester is a certain private chain or alliance chain, the node in the alliance chain or the private chain sends the stored original data to the requester; and if the authorization range of the requester is the expanded public chain, the node in the public chain sends the stored original data or feature data to the requester. According to the method and the system, the data in the alliance chain and/or the private chain can be authorized to more mechanisms, and the security of the data is ensured. 本申请涉及区块链技术领域，尤其涉及一种基于区块链的数据授权方法及系统，包括：区块链中的节点接收数据获取请求，并分析得到发出数据获取请求的请求方的授权范围；若请求方的授权范围为某一个私有链或联盟链，则该联盟链或私有链中的节点向请求方发送