Design of secure and trustworthy system-on-chip architectures using hardware-based root-of-trust techniques

Abstract

Cyber-security is now a critical concern in a wide range of embedded computing modules, communications systems, and connected devices. These devices are used in medical electronics, automotive systems, power grid systems, robotics, and avionics. The general consensus today is that conventional approaches and software-only schemes are not sufficient to provide desired security protections and trustworthiness.

Comprehensive hardware-software security solutions so far have remained elusive. One major challenge is that in current system-on-chip (SoCs) designs, processing elements (PEs) and executable codes with varying levels of trust, are all integrated on the same computing platform to share resources. This interdependency of modules creates a fertile attack ground and represents the Achilles’ heel of heterogeneous SoC architectures.

The salient research question addressed in this dissertation is “can one design a secure computer system out of non-secure or untrusted computing IP components and cores?”. In response to this question, we establish a generalized, user/designer-centric set of design principles which intend to advance the construction of secure heterogeneous multi-core computing systems. We develop algorithms, models of computation, and hardware security primitives to integrate secure and non-secure processing elements into the same chip design while aiming for: (a) maintaining individual core’s security; (b) preventing data leakage and corruption; (c) promoting data and resource sharing among the cores; and (d) tolerating malicious behaviors from untrusted processing elements and software applications.

The key contributions of this thesis are: 1. The introduction of a new architectural model for integrating processing elements with different security and trust levels, i.e., secure and non-secure cores with trusted and untrusted provenances;

2. A generalized process isolation design methodology for the new architecture model that covers both the software and hardware layers to (i) create hardware-assisted virtual logical zones, and (ii) perform both static and runtime security, privilege level and trust authentication checks;

3. A set of secure protocols and hardware root-of-trust (RoT) primitives to support the process isolation design and to provide the following functionalities: (i) hardware immutable identities – using physical unclonable functions, (ii) core hijacking and impersonation resistance – through a blind signature scheme, (iii) threshold-based data access control – with a robust and adaptive secure secret sharing algorithm, (iv) privacy-preserving authorization verification – by proposing a group anonymous authentication algorithm, and (v) denial of resource or denial of service attack avoidance – by developing an interconnect network routing algorithm and a memory access mechanism according to user-defined security policies.

4. An evaluation of the security of the proposed hardware primitives in the post-quantum era, and possible extensions and algorithmic modifications for their post-quantum resistance.

In this dissertation, we advance the practicality of secure-by-construction methodologies in SoC architecture design. The methodology allows for the use of unsecured or untrusted processing elements in the construction of these secure architectures and tries to extend their effectiveness into the post-quantum computing era.