US Patent 11636221 Mechanism for multi-factor authentication based on data

A request is received from a client seeking to access files stored at a backup server. A first tree is received for the request. The first tree represents hashes of files stored at the client. A second tree is generated representing hashes of the files stored at the backup server. The first and second trees are compared to assess a degree of similarity between the files stored at the client and the files stored at the backup server. The user is denied access to the files stored at the backup server when the degree of similarity is below a threshold.