1. Team Wolf Distributed, Consistent and Secure USB Storage Final Project Review Eddie Lai Matt Dube Sean Busch Zhou Zheng

2. Team Wolf 2 Backing Up Data  Everyone needs to save their work and data This data needs to be available in multiple locations Data needs to be readily available Today’s most popular storage device is the thumb drive  Backups have problems: reliability Can be physically broken Need to be carried around Can wear out after a number of reads/writes  Reliability problem often solved by multiple backups  Multiple backups: consistency problems Data changes create inconsistencies between backups When many backups are created, data becomes vulnerable

3. Team Wolf 3 Distributed Consistent Secure USB Hub  Our project: Distributed Consistent Secure USB Hub  Uses off-the-shelf USB drives for storage  Looks like a mass storage device to user’s PC  Distributed Can be accessed anywhere without any software installation  Consistent Storage Devices at different locations get updated Synchronization as easy as a push of a button  Secure Secret sharing prevents users’ data from being compromised

4. Team Wolf 4 Outline  Introduction  System Operation PC Interface File Consistency Software Hub Communication User Interface Secret Sharing Software  Prototype  Budget & Team Roles  Demonstration

5. Team Wolf 5  Special hubs  Hubs are interfaced with PCs, networked with each other  Groups of USB drives  User updates file on USB drive from PC  Updates sent to other USB drives in the group Project Summary

6. Team Wolf 6 Current Solutions  There are currently several different services that allow users to back up data and access it anywhere  Dropbox, Google Docs  Functionality based on users releasing their data to the cloud  Some information may be too sensitive to store there  Project gives user added control over their data  Users possess the physical media their data is stored on

7. Team Wolf 7 Hub Design  Built on embedded PC  Memory To boot OS  A Network Interface  USB On the Go Port  USB Ports  User interface  Consistency Software

8. Team Wolf 8 PC Interface  Hub connects to PC without any software installation Not all users will be allowed to install software on their PC  Hub appears as a USB mass storage device  Use USB OTG port By interfacing with the PC via this port, board appears as USB device Shows contents of attached USB drives

9. Team Wolf 9 File Consistency Software  Custom software to recognize when updates are made  Will only run on “trusted” USBs based on UUID  Changes recognized using conventional UNIX tools Timestamps and checksums recorded, then “diff”ed with previous record Timestamp modified Timestamp unmodified CRC modified File has been added. Distribute file to other hubs CRC not modified File has been touched. Distribute timestamp change only No file updates have been made

10. Team Wolf 10 Hub Communication  Upon synchronization, the hubs will distribute updates across the network When a hub is distributing updates, it will act as a client The receiving hub will act as the server  TCP Client/Server Model Secure using SSL  Each client will connect to a server, distribute its updates, then disconnect

11. Team Wolf 11 User Interface  Hub is manually operated by user  Simple user interface consists of two buttons One button initiates synchronization One button ejects USB sticks  Buttons are mounted on Hub via embedded PC’s GPIO ports  Two LEDs provide feedback for users One alerts user when a sync is in progress The other shows when it is safe to remove USBs from hub

12. Team Wolf 12 Secret Sharing  User has option to share information secretly with other hubs  If a USB drive is lost or compromised, no useful information about its contents can be recovered  (k,n) Threshold scheme: need k of n USBs to recover data  Implements Shamir's [1] secret sharing in the Galois Field  Functionality partially provided by libgfshare UNIX library [1] Shamir, Adi (1979), "How to share a secret", Communications of the ACM 22 (11): 612– 613, doi:10.1145/359168.359176.

13. Team Wolf 13 Prototype  Our Hub is currently being prototyped on the BeagleBoard-xM  Board offers a slimmer form factor Allows for portability while still containing all of the necessary peripherals − 4 USB ports, Ethernet port Solid state memory (using microSD card)  Primary motivation for using BeagleBoard is its USB OTG port Allows the board to be mounted on User’s PC as USB mass storage device

14. Team Wolf 14 Budget and Team Roles  Hub Costs: BeagleBoard-xM: $150 Enclosure: $40 2 LEDs with mounts:$4 2 Buttons:$10 USB 2.0 A Male to Micro-USB B: $8  Estimated cost of production: $150-$175 per hub  Eddie: Consistency Software, Hub Communication  Matt: Prototype setup, USB Interface  Zhou: Website, User Interface  Sean: USB Interface

15. Team Wolf 15 Project Summary  Distributed Consistent Secure USB Hub allows user to keep backups on multiple USB sticks consistent  Hub simplifies process for user Hub appears as USB mass storage device Doesn’t require software installation on user’s PC Simple user interface allows hub to be operated with only two buttons  Hub distributes updates to backups securely across network  User has optional secret sharing functionality  Prototype built using BeagleBoard-xM

16. Team Wolf 16 Demonstration  Non Secret Sharing Scenario 1: Hub1 adds multiple files Scenario 2: Hub2 removes file  Secret Sharing Scenario 1: Hub1 adds multiple files Scenario 2: Hub1 recreates a secret with all n shares present Scenario 3: Hub2 recreates a secret with n-1 shares present