Encrypted File System Lab
SEED Lab: A Hands-on Lab for Security Education
Overview
In a traditional file system, files are usually stored on disks unencrypted. When the disks are stolen by someone, contents of those files can be easily recovered by the malicious people. To protect files even when the disks are stolen, we can use encryption tools to encrypt files. For example, we can use ``pgp'' command to encrypt files. However, this is quite inconvenient; users need to decrypt a file before editing the file, and then remember to encrypt it afterward. It will be better if encryption and decryption can be transparant to users. Encrypted File System (EFS) is developed for such a purpose, and it has been implemented in a number of operating systems, such as Solaris, Windows NT, and Linux.
Lab Tasks (Description)
- For instructors: if you prefer to customize the lab description to suit your own courses, here are our Latex source files.
- Operating System: This lab needs to be carried out in the Minix 3 operating system.
Recommended Time: 4 weeks
Files and Helping Materials
- AES, MD5, SHA-256, HMAC-MD5 code. To use the code in variouls places within Minix, it is better to to create a crypto library in Minix.
- How to add a new system call in Minix 3
- How is a system call invoked in Minix 3
- How to manipulate the Inode data structure
- How to define a new file system
- Three process tables in Minix 2 (Minix 3 might be different)
- Matt Blaze, A Cryptographic File System for Unix
- Zadok et al. Cryptfs: A Stackable Vnode Level Encryption File System