27,255 research outputs found
Ubic: Bridging the gap between digital cryptography and the physical world
Advances in computing technology increasingly blur the boundary between the
digital domain and the physical world. Although the research community has
developed a large number of cryptographic primitives and has demonstrated their
usability in all-digital communication, many of them have not yet made their
way into the real world due to usability aspects. We aim to make another step
towards a tighter integration of digital cryptography into real world
interactions. We describe Ubic, a framework that allows users to bridge the gap
between digital cryptography and the physical world. Ubic relies on
head-mounted displays, like Google Glass, resource-friendly computer vision
techniques as well as mathematically sound cryptographic primitives to provide
users with better security and privacy guarantees. The framework covers key
cryptographic primitives, such as secure identification, document verification
using a novel secure physical document format, as well as content hiding. To
make a contribution of practical value, we focused on making Ubic as simple,
easily deployable, and user friendly as possible.Comment: In ESORICS 2014, volume 8712 of Lecture Notes in Computer Science,
pp. 56-75, Wroclaw, Poland, September 7-11, 2014. Springer, Berlin, German
Chip and Skim: cloning EMV cards with the pre-play attack
EMV, also known as "Chip and PIN", is the leading system for card payments
worldwide. It is used throughout Europe and much of Asia, and is starting to be
introduced in North America too. Payment cards contain a chip so they can
execute an authentication protocol. This protocol requires point-of-sale (POS)
terminals or ATMs to generate a nonce, called the unpredictable number, for
each transaction to ensure it is fresh. We have discovered that some EMV
implementers have merely used counters, timestamps or home-grown algorithms to
supply this number. This exposes them to a "pre-play" attack which is
indistinguishable from card cloning from the standpoint of the logs available
to the card-issuing bank, and can be carried out even if it is impossible to
clone a card physically (in the sense of extracting the key material and
loading it into another card). Card cloning is the very type of fraud that EMV
was supposed to prevent. We describe how we detected the vulnerability, a
survey methodology we developed to chart the scope of the weakness, evidence
from ATM and terminal experiments in the field, and our implementation of
proof-of-concept attacks. We found flaws in widely-used ATMs from the largest
manufacturers. We can now explain at least some of the increasing number of
frauds in which victims are refused refunds by banks which claim that EMV cards
cannot be cloned and that a customer involved in a dispute must therefore be
mistaken or complicit. Pre-play attacks may also be carried out by malware in
an ATM or POS terminal, or by a man-in-the-middle between the terminal and the
acquirer. We explore the design and implementation mistakes that enabled the
flaw to evade detection until now: shortcomings of the EMV specification, of
the EMV kernel certification process, of implementation testing, formal
analysis, or monitoring customer complaints. Finally we discuss
countermeasures
Protecting Private Data in the Cloud
Companies that process business critical and secret data are reluctant
to use utility and cloud computing for the risk that their data gets
stolen by rogue system administrators at the hosting company. We
describe a system organization that prevents host administrators from
directly accessing or installing eaves-dropping software on the
machine that holds the client's valuable data. Clients are monitored
via machine code probes that are inlined into the clients' programs at
runtime. The system enables the cloud provider to install and remove software
probes into the machine code without stopping the client's program, and
it prevents the provider from installing probes not granted by the
client
Creation and detection of hardware trojans using non-invasive off-the-shelf technologies
As a result of the globalisation of the semiconductor design and fabrication processes, integrated circuits are becoming increasingly vulnerable to malicious attacks. The most concerning threats are hardware trojans. A hardware trojan is a malicious inclusion or alteration to the existing design of an integrated circuit, with the possible effects ranging from leakage of sensitive information to the complete destruction of the integrated circuit itself. While the majority of existing detection schemes focus on test-time, they all require expensive methodologies to detect hardware trojans. Off-the-shelf approaches have often been overlooked due to limited hardware resources and detection accuracy. With the advances in technologies and the democratisation of open-source hardware, however, these tools enable the detection of hardware trojans at reduced costs during or after production. In this manuscript, a hardware trojan is created and emulated on a consumer FPGA board. The experiments to detect the trojan in a dormant and active state are made using off-the-shelf technologies taking advantage of different techniques such as Power Analysis Reports, Side Channel Analysis and Thermal Measurements. Furthermore, multiple attempts to detect the trojan are demonstrated and benchmarked. Our simulations result in a state-of-the-art methodology to accurately detect the trojan in both dormant and active states using off-the-shelf hardware
Agent-Based Simulations of Blockchain protocols illustrated via Kadena's Chainweb
While many distributed consensus protocols provide robust liveness and
consistency guarantees under the presence of malicious actors, quantitative
estimates of how economic incentives affect security are few and far between.
In this paper, we describe a system for simulating how adversarial agents, both
economically rational and Byzantine, interact with a blockchain protocol. This
system provides statistical estimates for the economic difficulty of an attack
and how the presence of certain actors influences protocol-level statistics,
such as the expected time to regain liveness. This simulation system is
influenced by the design of algorithmic trading and reinforcement learning
systems that use explicit modeling of an agent's reward mechanism to evaluate
and optimize a fully autonomous agent. We implement and apply this simulation
framework to Kadena's Chainweb, a parallelized Proof-of-Work system, that
contains complexity in how miner incentive compliance affects security and
censorship resistance. We provide the first formal description of Chainweb that
is in the literature and use this formal description to motivate our simulation
design. Our simulation results include a phase transition in block height
growth rate as a function of shard connectivity and empirical evidence that
censorship in Chainweb is too costly for rational miners to engage in. We
conclude with an outlook on how simulation can guide and optimize protocol
development in a variety of contexts, including Proof-of-Stake parameter
optimization and peer-to-peer networking design.Comment: 10 pages, 7 figures, accepted to the IEEE S&B 2019 conferenc
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