US Patent 10162967 Methods and systems for identifying legitimate computer files

A system for evaluating a target file includes an endpoint computer that receives similarity digests of legitimate files, receives a target file, and generates a similarity digest of the target file. The endpoint computer determines whether or not the target file is legitimate based on a comparison of the similarity digest of the target file against the similarity digests of the legitimate files. The system further includes a backend computer system that receives the legitimate files, generates the similarity digests of the legitimate files, and provides the similarity digests of the legitimate files to the endpoint computer.