1. 4. NCdisk SP-based SoC Architecture 5. NCdisk Security Protocol
Architecture for Non-Copyable Disk (NCdisk) Using a Secret-Protection (SP) SoC Solution Michael S. Wang and Ruby B. Lee Department of Electrical Engineering, Princeton University
1. Introduction
Problem of study: Digital contents piracy
Research: Examined both software and hardware vulnerabilities in existing copy-protection methods.
Proposal: Proposed a non-copyable disk (NCdisk) that makes it significantly harder for digital contents to be copied. Any digital content written onto the NCdisk can only be read through a predefined set of NCdisk outputs.
4. NCdisk SP-based SoC Architecture
The NCdisk concept ultimately boils down to achieving two goals.
The first goal is to protect secret keys inside the NCdisk.
The second goal is to protect data output such that the original digital plaintext data is never leaked out.
We achieve these two goals by implementing a SoC consisting of existing disk controller components, plus a minimal set of additions. This new SoC can then be connected to the rest of the existing disk components to turn an existing disk into an NCdisk.
5. NCdisk Security Protocol
We present a security protocol to use along with the NCdisk for an online movie download application.
Manufacturer sends a blank NCdisk to Content Provider (CP), who initializes the NCdisk.
NCdisk Architecture
Existing Hard Disk Architecture
2. Threat Model
Content provider’s software is trusted and is allowed to use the critical secrets but cannot leak these secrets out.
Any other software is un-trusted and is not allowed to use the secrets.
The attacker is able to mount software attacks.
Probing inside a System-on-Chip (SOC) is more difficult without destroying functionality, so it is not in our threat model.
We also do not consider side-channel attacks.
User buys an NCdisk from store and then connects to CP through Internet.
SP Instructions for the NCdisk Processor
SP Instruction
Description
Begin_TSM (on-chip ROM )
Begins execution of TSM (enables access of TSM scratchpad memory)
End_TSM (on or off-chip)
ends execution of TSM (disables access of TSM scratchpad memory)
SecureMem_Set (on or off-chip)
Sets StartAddr & EndAddr registers to define TSM scratchpad memory
DeviceKey_Read (on or off-chip)
Load the Device Key to be used by TSM SW
3. NCdisk Concept
The NCdisk is a data storage device, in which any digital content written into the device is automatically encrypted using a key that is generated by the NCdisk that never leaves the NCdisk.
All data stored on the NCdisk are encrypted. It can only be read through a set of predefined outputs, such that the digital plaintext form of the data never leaves the NCdisk.
CP prepares a movie for the NCdisk
NCdisk APIs for Applications
API Functions
Description
TSM_Write
Write data into NCdisk
TSM_Read_Analog
Output to analog channel
TSM_Read_Trusted
Output to trusted display
TSM_Read_Integrated
Output to internal display
NCdisk stores the downloaded movie
Reference
Michael Wang and Ruby Lee, “Architecture of Non-Copyable Disk (NCdisk) Using Secret-Protection (SP) SoC Solution”, Forty-First Asilomar Conference on Signals, Systems and Computers, November 4-7, 2007.
Jeffrey S Dwoskin, Ruby B. Lee, "Hardware-rooted Trust for Secure Key Management and Transient Trust", ACM Conference on Computer and Communications Security, pp , October 2007.
Jeffrey Dwoskin, Dahai Xu, Jianwei Huang, Mung Chiang, Ruby Lee, "Secure Key Management Architecture Against Sensor-node Fabrication Attacks", IEEE GlobeCom 2007, November 2007.