359 research outputs found
Privacy Leakages in Approximate Adders
Approximate computing has recently emerged as a promising method to meet the
low power requirements of digital designs. The erroneous outputs produced in
approximate computing can be partially a function of each chip's process
variation. We show that, in such schemes, the erroneous outputs produced on
each chip instance can reveal the identity of the chip that performed the
computation, possibly jeopardizing user privacy. In this work, we perform
simulation experiments on 32-bit Ripple Carry Adders, Carry Lookahead Adders,
and Han-Carlson Adders running at over-scaled operating points. Our results
show that identification is possible, we contrast the identifiability of each
type of adder, and we quantify how success of identification varies with the
extent of over-scaling and noise. Our results are the first to show that
approximate digital computations may compromise privacy. Designers of future
approximate computing systems should be aware of the possible privacy leakages
and decide whether mitigation is warranted in their application.Comment: 2017 IEEE International Symposium on Circuits and Systems (ISCAS
SRAM PUF์ ์ ๋ขฐ์ฑ ๊ฐ์ ์ ์ํ ์ ์ ๊ณต๊ธ ๊ธฐ๋ฒ
ํ์๋
ผ๋ฌธ (์์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ์ตํฉ๊ณผํ๊ธฐ์ ๋ํ์ ์ตํฉ๊ณผํ๋ถ(์ง๋ฅํ์ตํฉ์์คํ
์ ๊ณต), 2021. 2. ์ ๋์.PUF (Physically Unclonable Function)์ ํ๋์จ์ด ๋ ๋ฒจ์ ์ธ์ฆ ๊ณผ ์ ์์ ๋๋ฆฌ ์ด์ฉ๋๋ ๋ฐฉ๋ฒ์ด๋ค. ๊ทธ ์ค์์๋ SRAM PUF๋ ๊ฐ์ฅ ์ ์ ๋ ค์ง PUF์ ๋ฐฉ๋ฒ๋ก ์ด๋ค. ๊ทธ๋ฌ๋ ์์ธก ๋ถ๊ฐ๋ฅํ ๋์์ผ๋ก ์ธํด ๋ฐ์๋๋ ๋ฎ์ ์ฌ์์ฐ์ฑ๊ณผ ์ ์ ๊ณต๊ธ ๊ณผ์ ์์ ๋ฐ์ํ๋ ๋
ธ์ด์ฆ์ ๋ฌธ์ ๋ฅผ ๊ฐ์ง๊ณ ์๋ค. ๋ณธ ๋
ผ๋ฌธ์์๋ ํจ๊ณผ์ ์ผ๋ก SRAM PUF์ ์ฌ์์ฐ์ฑ์ ํฅ์์ํฌ ์ ์๋ ๋ ๊ฐ์ง ์ ์ ๊ณต๊ธ ๊ธฐ๋ฒ์ ์ ์ํ๋ค. ์ ์ํ ๊ธฐ๋ฒ๋ค์ ๊ฐ์ด ์ฐ์ถ๋ ๋ ์์ญ ํน์ ์ ์ ๊ณต๊ธ์์ ๊ธฐ์ธ๊ธฐ(ramp-up ์๊ฐ)๋ฅผ ์กฐ์ ํจ์ผ๋ก์จ ์ ํ์ง ์๋ ๋นํธ์ ๋ค์งํ(flipping) ํ์์ ์ค์ธ๋ค. 180nm ๊ณต์ ์ผ๋ก ์ ์๋ ํ
์คํธ ์นฉ์ ์ด์ฉํ ์ธก์ ๊ฒฐ๊ณผ ์ฌ์์ฐ์ฑ์ด 2.2๋ฐฐ ํฅ์๋์์ ๋ฟ๋ง ์๋๋ผ NUBs(Native Unstable Bits)๋ 54.87% ๊ทธ๋ฆฌ๊ณ BER (Bit Error Rate)๋ 55.05% ๊ฐ์ํ ๊ฒ์ ํ์ธํ์๋ค.Physically unclonable function (PUF) is a widely used hardware-level identification method. SRAM-based PUFs are the most well-known PUF topology, but they typically suffer from low reproducibility due to non-deterministic behaviors and noise during power-up process. In this work, we propose two power-up control techniques that effectively improve reproducibility of the SRAM PUFs. The techniques reduce undesirable bit flipping during evaluation by controlling either evaluation region or power supply ramp-up speed. Measurement results from the 180 nm test chip confirm that native unstable bits (NUBs) are reduced by 54.87% and bit error rate (BER) decreases by 55.05% while reproducibility increases by 2.2ร.Chapter 1 Introduction 1
1.1 PUF in Hardware Securit 1
1.2 Prior Works and Motivation 2
Chapter 2 Related works and Motivation 5
2.1 Uniqueness 7
2.2 Reproducibility 7
2.3 Hold Static Noise Margin (SNM) 8
2.4 Bit Error Rate (BER) 9
2.5 PUF Static Noise Margin Ratio (PSNMratio) 9
Chapter 3 Microarchitecture-Aware Code Generation 11
3.1 Scheme 1: Developing Fingerprint in Sub-Threshold Region 13
3.2 Scheme 2: Controlling Voltage Ramp-up Speed 17
Chapter 4 Experimental Evaluation 19
4.1 Experimental Setup 19
4.2 Evaluation Results 21
Chapter 5 Conclusion 28
Bibliography 29
Abstract in Korean 33Maste
SecuCode: Intrinsic PUF Entangled Secure Wireless Code Dissemination for Computational RFID Devices
The simplicity of deployment and perpetual operation of energy harvesting
devices provides a compelling proposition for a new class of edge devices for
the Internet of Things. In particular, Computational Radio Frequency
Identification (CRFID) devices are an emerging class of battery-free,
computational, sensing enhanced devices that harvest all of their energy for
operation. Despite wireless connectivity and powering, secure wireless firmware
updates remains an open challenge for CRFID devices due to: intermittent
powering, limited computational capabilities, and the absence of a supervisory
operating system. We present, for the first time, a secure wireless code
dissemination (SecuCode) mechanism for CRFIDs by entangling a device intrinsic
hardware security primitive Static Random Access Memory Physical Unclonable
Function (SRAM PUF) to a firmware update protocol. The design of SecuCode: i)
overcomes the resource-constrained and intermittently powered nature of the
CRFID devices; ii) is fully compatible with existing communication protocols
employed by CRFID devices in particular, ISO-18000-6C protocol; and ii) is
built upon a standard and industry compliant firmware compilation and update
method realized by extending a recent framework for firmware updates provided
by Texas Instruments. We build an end-to-end SecuCode implementation and
conduct extensive experiments to demonstrate standards compliance, evaluate
performance and security.Comment: Accepted to the IEEE Transactions on Dependable and Secure Computin
TuRaN: True Random Number Generation Using Supply Voltage Underscaling in SRAMs
Prior works propose SRAM-based TRNGs that extract entropy from SRAM arrays.
SRAM arrays are widely used in a majority of specialized or general-purpose
chips that perform the computation to store data inside the chip. Thus,
SRAM-based TRNGs present a low-cost alternative to dedicated hardware TRNGs.
However, existing SRAM-based TRNGs suffer from 1) low TRNG throughput, 2) high
energy consumption, 3) high TRNG latency, and 4) the inability to generate true
random numbers continuously, which limits the application space of SRAM-based
TRNGs. Our goal in this paper is to design an SRAM-based TRNG that overcomes
these four key limitations and thus, extends the application space of
SRAM-based TRNGs. To this end, we propose TuRaN, a new high-throughput,
energy-efficient, and low-latency SRAM-based TRNG that can sustain continuous
operation. TuRaN leverages the key observation that accessing SRAM cells
results in random access failures when the supply voltage is reduced below the
manufacturer-recommended supply voltage. TuRaN generates random numbers at high
throughput by repeatedly accessing SRAM cells with reduced supply voltage and
post-processing the resulting random faults using the SHA-256 hash function. To
demonstrate the feasibility of TuRaN, we conduct SPICE simulations on different
process nodes and analyze the potential of access failure for use as an entropy
source. We verify and support our simulation results by conducting real-world
experiments on two commercial off-the-shelf FPGA boards. We evaluate the
quality of the random numbers generated by TuRaN using the widely-adopted NIST
standard randomness tests and observe that TuRaN passes all tests. TuRaN
generates true random numbers with (i) an average (maximum) throughput of
1.6Gbps (1.812Gbps), (ii) 0.11nJ/bit energy consumption, and (iii) 278.46us
latency
NoisFre: Noise-Tolerant Memory Fingerprints from Commodity Devices for Security Functions
Building hardware security primitives with on-device memory fingerprints is a
compelling proposition given the ubiquity of memory in electronic devices,
especially for low-end Internet of Things devices for which cryptographic
modules are often unavailable. However, the use of fingerprints in security
functions is challenged by the small, but unpredictable variations in
fingerprint reproductions from the same device due to measurement noise. Our
study formulates a novel and pragmatic approach to achieve highly reliable
fingerprints from device memories. We investigate the transformation of raw
fingerprints into a noise-tolerant space where the generation of fingerprints
is intrinsically highly reliable. We derive formal performance bounds to
support practitioners to easily adopt our methods for applications.
Subsequently, we demonstrate the expressive power of our formalization by using
it to investigate the practicability of extracting noise-tolerant fingerprints
from commodity devices. Together with extensive simulations, we have employed
119 chips from five different manufacturers for extensive experimental
validations. Our results, including an end-to-end implementation demonstration
with a low-cost wearable Bluetooth inertial sensor capable of on-demand and
runtime key generation, show that key generators with failure rates less than
can be efficiently obtained with noise-tolerant fingerprints with a
single fingerprint snapshot to support ease-of-enrollment.Comment: Accepted to IEEE Transactions on Dependable and Secure Computing.
Yansong Gao and Yang Su contributed equally to the study and are co-first
authors in alphabetical orde
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