Multi-identity for secure file sharing

Abstract

Techniques for controlling access to shared data files such as stored in a collaborative file sharing service. Organizations want to have access to data originated by their employees and want that access to continue even when the employees leave the company. Also, organizations do not want former employees to have access to the company's files. A file storage service uses an Organization's recovery key while creating a recovery record for a file (which may be stored in a folder), and protected using a Work identity. The individual person who originally creates a file and/or shares a folder securely with others is considered the folder's owner as long as he is part of the same Organization. User's identities are validated upon access. The keys are also purged from a local key store as soon as identity changes are detected. In this way, the folder owner will not be able to decrypt files stored in a folder shared using a Work identity if the identity is canceled by the Organization.