File system encryption with integrated user management

Abstract

Existing cryptographic file systems for Unix do not take into account that sensitive data must often be shared with other users, but still kept secret. By design, the only one who has access to the secret data is the person who encrypted it and therefore knows the encryption key or password. This paper presents a kernel driver for a new encrypted file system, called Fairly Secure File System (FSFS), which provides mechanisms for user management and access control for encrypted files. The driver has been specifically designed with multi user systems in mind. FSFS also tries to prevent unintentional transfer of sensitive data to unencrypted file systems, where it would be stored in plaintext.