Business processing method and device based on block chain

The embodiment of the invention provides a business processing method and device based on a block chain, and relates to the technical field of block chains. The method comprises the steps of obtainingrisk assessment information obtained by performing risk assessment on a target user, and obtaining digital identity information corresponding to the target user; according to the digital identity information and the risk assessment information, creating a first verifiable declaration of the risk assessment information corresponding to the digital identity information through a first block chain;uploading the content data of the first verifiable declaration to a second block chain, obtaining an evidence storage credential of the content data on the second block chain, and generating a risk assessment card corresponding to the target user according to the obtained evidence storage credential and the first verifiable declaration; wherein the second block chain is linked to the business processing platform, and the r