1. Overview on Hardware Security
Electronic Design Contest

2. Outline Overview of modern cryptography
Modern hardware design practices
Example of Hardware Attacks
Introduction to Side Channel Analysis
Differential fault analysis of ciphers
Cache attacks on ciphers
Power analysis of cipher implementations
Testability of cryptographic hardware
Overview of Hardware Trojans

3. Hardware Security
Definition: implement security protection mechanisms in hardware
E.g., design trusted hardware, as opposed to (in addition to) trusted software
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4. Trusted or Trustworthy
A component of a system is trusted means that
the security of the system depends on it
failure of component can break the security policy
determined by its role in the system
A component is trustworthy means that
the component deserves to be trusted
e.g., it is implemented correctly
determined by intrinsic properties of the component
Trusted or trustworthy computation?
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5. Why Hardware Security Software security: software protect software!
Vulnerable to attacks
Is the antivirus/hardware untouched?
Easy infiltration
Fast spread
Hardware security: hardware protect software
Attacks need physical access
Software infiltration much more difficult
CS660 - Advanced Information Assurance - UMassAmherst

6. Overview of Modern Cryptography

7. Introduction Cryptography: protect information from illegal access.
In the last three decades, cryptography has grown beyond designing ciphers to encompass also other activities like design of signature schemes for signing digital contracts.
The design of cryptographic protocols for securely proving one’s identity has been an important aspect of cryptography of the modern age.
Yet the construction of encryption schemes remains, and is likely to remain, a central enterprise of cryptography

8. Cryptography: Some Technical Details
The aim of the cryptographer is to find methods to secure and authenticate messages.
Secret key cryptosystem model

9. Cryptography: Some Technical Details
Example of Cryptographic Algorithm:
Block Ciphers (Example: AES)
RSA
Elliptic Curve Cryptosystems
BC3

10. Modern Hardware Design Practices

11. Introduction
Design of cryptographic algorithms in dedicated hardware provides significant opportunities for speed up due to their parallelism.
Field Programmable Gate Arrays (FPGAs) are reconfigurable platforms to build hardware.
Advantage:
Hardware: in extracting parallelism, and achieving better performance
Software: in terms of programmability.

12. FPGA Architecture
FPGAs are reconfigurable devices offering parallelism and flexibility, on one hand, while being low cost and easy to use on the other. Moreover, they have much shorter design cycle times compared to ASICs.
The reconfigurability aspect of FPGAs also makes them suited for cryptographic applications.
FPGAs do not require sophisticated equipment for production, they can be programmed in house. This is a distinct advantage for cryptography as no third party is involved, thus increasing trust in the hardware circuit

13. FPGA Architecture
FPGA island-style architecture
FPGA Logic Block

14. FPGA Architecture
The FPGA design flow

15. Mapping an Algorithm to Hardware
Important Components of an Architecture

16. Enhancing the Performance of a Hardware Design
Performance of a hardware design is often stated through:
Critical path, by limiting the clock frequency.
Resource consumed (customize the design for the target architecture to ensure that the resource used is minimized)

17. Example of Hardware Attacks
Side Channel Analysis
Differential fault analysis of ciphers
Cache attacks on chippers
Power analysis of chipper implementations

18. Side Channel Analysis
Examples of such side channels are timing, power, electromagnetic radiations, visual, acoustics, cache, testability features of hardware devices and there may be many more.
A very closely related class of attacks is called as fault attacks, where the device under the induction of faults, perform wrong computations.
The adversary uses the correct ciphertexts and the faulty ciphertexts and obtains the keys.

19. Side Channel Analysis
Side Channel Attacks

20. Side Channel Analysis
Examples of such side channels are timing, power, electromagnetic radiations, visual, acoustics, cache, testability features of hardware devices and there may be many more.
A very closely related class of attacks is called as fault attacks, where the device under the induction of faults, perform wrong computations.
The adversary uses the correct ciphertexts and the faulty ciphertexts and obtains the keys.

21. Side Channel Analysis
There are several forms of popular side channels attacks on hardware and embedded systems are:
Timing Attacks
Power Attacks
Fault Attacks
Design for Testability attacks
Cache Attacks

22. Differential Fault Analysis of Cipher
The first fault attack was applied to the RSA cryptosytem.
Biham and Shamir proposed a new fault based attacking technique which is wildly known as Differential Fault Analysis (DFA)
DFA attack is a very powerful attack model which can threaten a large class of ciphers.
As the faults are induced during the encryption process, the fault propagation patterns give some relations between the input and output difference if certain S-boxes.

23. Differential Fault Analysis of Cipher
Three steps of DFA.

24. Differential Fault Analysis of Cipher
The faults can be of varying nature but can be categorized as follows:
Bit model
Single byte
Multiple byte

25. Cache attacks on chippers
Memory Hierarchy Structure

26. Cache attacks on chippers
Example of cache attacks:
Trace-driven cache attacks
Trace-driven attacks on AES
Trace-driven attacks based on included cache miss
Access-driven cache attacks
Access-driven attacks on Block chipper
Asynchronous access-driven attacks

27. Power analysis of chipper implementations
A successful power attack on a cryptographic device requires proper understanding of the power characteristic of the device.
However, the central requirement of a power attack is the capability to obtain an accurate power trace.

28. Power analysis of chipper implementations
(a) Laboratory Setup for Power Analysis
(b) Components of a Power Attack Setup

29. Testability of Cryptographic Hardware

30. Introduction
Scan chains are the most popular testing technique due to their high fault coverage and least hardware overhead.
Scan chains are used to access intermediate values stored in the flip-flops, thereby, ascertaining the secret information, often known as key.
These attack techniques exploit the fact that most of modern day ICs are designed for testability.

31. Introduction Example of Scan Attacks
Scan Chain Based Attacks on Cryptographic Implementations
Scan Chain Based Attack on Stream Ciphers

32. Overview on Hardware Trojan

33. Introduction
Hardware Trojan attacks relate to malicious modifications of an IC during design or fabrication in an untrusted design house or foundry, which involve untrusted people, design tools, or components.
This modifications can give rise to undesired functional behavior of an IC, or provide convert channels or backdoor through which sensitive information can be leaked.
General structure of a hardware Trojan in design

34. Introduction
Hardware Trojan attacks by different parties at different stages of IC life cycle

35. Trojan Taxonomy
Trojan taxonomy based on trigger and payload mechanisms

36. Thank you