Patent ID: 11954221
Assignee: EMC IP HOLDING COMPANY LLC
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 10:
11. A computer program product, comprising a non-transitory computer-readable medium having a computer-readable program code embodied therein, the computer-readable program code adapted to be executed by one or more processors to implement a method of authentication, the method comprising:
receiving a request from a user at a client to access a file of a set of files backed up to a backup server;
upon verifying a password provided by the user, issuing to the client another request for authentication;
receiving, responsive to the authentication request, a first data structure generated using identifiers corresponding to a set of files at the client of which at least some presumably have been backed up to the backup server;
generating a second data structure using identifiers corresponding to the set of files backed up to the backup server;
comparing the first and second data structures to assess a degree of similarity between the set of files at the client and the set of files backed up to the backup server; and
denying the user access to the file when the degree of similarity is below a threshold, wherein the first and second data structures comprise tree data structures.