A Mathematical Theory of Communication

THE recent development of various methods of modulation such as PCM and PPM which exchange
bandwidth for signal-to-noise ratio has intensified the interest in a general theory of communication. A
basis for such a theory is contained in the important papers of Nyquist1 and Hartley2 on this subject. In the
present paper we will extend the theory to include a number of new factors, in particular the effect of noise
in the channel, and the savings possible due to the statistical structure of the original message and due to the
nature of the final destination of the information.

Source: http://math.harvard.edu/~ctm/home/text/others/shannon/entropy/entropy.pdf

Advertisements

Blocking-resistant communication through domain fronting

Abstract: We describe “domain fronting,” a versatile
censorship circumvention technique that hides the remote
endpoint of a communication. Domain fronting
works at the application layer, using HTTPS, to communicate
with a forbidden host while appearing to communicate
with some other host, permitted by the censor.
The key idea is the use of different domain names at
different layers of communication. One domain appears
on the “outside” of an HTTPS request—in the DNS request
and TLS Server Name Indication—while another
domain appears on the “inside”—in the HTTP Host
header, invisible to the censor under HTTPS encryption.
A censor, unable to distinguish fronted and nonfronted
traffic to a domain, must choose between allowing
circumvention traffic and blocking the domain entirely,
which results in expensive collateral damage. Domain
fronting is easy to deploy and use and does not require
special cooperation by network intermediaries. We
identify a number of hard-to-block web services, such as
content delivery networks, that support domain-fronted
connections and are useful for censorship circumvention.
Domain fronting, in various forms, is now a circumvention
workhorse. We describe several months of deployment
experience in the Tor, Lantern, and Psiphon circumvention
systems, whose domain-fronting transports
now connect thousands of users daily and transfer many
terabytes per month.

Source: https://www.bamsoftware.com/papers/fronting.pdf

Examining the costs and causes of cyber incidents | Journal of Cybersecurity | Oxford Academic

Abstract
In 2013, the US President signed an executive order designed to help secure the nation’s critical infrastructure from cyberattacks. As part of that order, he directed the National Institute for Standards and Technology (NIST) to develop a framework that would become an authoritative source for information security best practices. Because adoption of the framework is voluntary, it faces the challenge of incentivizing firms to follow along. Will frameworks such as that proposed by NIST really induce firms to adopt better security controls? And if not, why? This research seeks to examine the composition and costs of cyber events, and attempts to address whether or not there exist incentives for firms to improve their security practices and reduce the risk of attack. Specifically, we examine a sample of over 12 000 cyber events that include data breaches, security incidents, privacy violations, and phishing crimes. First, we analyze the characteristics of these breaches (such as causes and types of information compromised). We then examine the breach and litigation rate, by industry, and identify the industries that incur the greatest costs from cyber events. We then compare these costs to bad debts and fraud within other industries. The findings suggest that public concerns regarding the increasing rates of breaches and legal actions may be excessive compared to the relatively modest financial impact to firms that suffer these events. Public concerns regarding the increasing rates of breaches and legal actions, conflict, however, with our findings that show a much smaller financial impact to firms that suffer these events. Specifically, we find that the cost of a typical cyber incident in our sample is less than $200 000 (about the same as the firm’s annual IT security budget), and that this represents only 0.4% of their estimated annual revenues.

Source: https://academic.oup.com/cybersecurity/article/2/2/121/2525524/Examining-the-costs-and-causes-of-cyber-incidents

Cutting the Cord: a Robust Wireless Facilities Network for Data Centers

Today’s network control and management traffic are limited by
their reliance on existing data networks. Fate sharing in this context
is highly undesirable, since control traffic has very different availability
and traffic delivery requirements. In this paper, we explore
the feasibility of building a dedicated wireless facilities network for
data centers. We propose Angora, a low-latency facilities network
using low-cost, 60GHz beamforming radios that provides robust
paths decoupled from the wired network, and flexibility to adapt to
workloads and network dynamics. We describe our solutions to address
challenges in link coordination, link interference and network
failures. Our testbed measurements and simulation results show
that Angora enables large number of low-latency control paths to
run concurrently, while providing low latency end-to-end message
delivery with high tolerance for radio and rack failures.

Source: https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/43860.pdf

Trumpet: Timely and Precise Triggers in Data Centers

As data centers grow larger and strive to provide tight performance
and availability SLAs, their monitoring infrastructure
must move from passive systems that provide aggregated
inputs to human operators, to active systems that enable programmed
control. In this paper, we propose Trumpet, an
event monitoring system that leverages CPU resources and
end-host programmability, to monitor every packet and report
events at millisecond timescales. Trumpet users can express
many network-wide events, and the system efficiently detects
these events using triggers at end-hosts. Using careful design,
Trumpet can evaluate triggers by inspecting every packet at
full line rate even on future generations of NICs, scale to
thousands of triggers per end-host while bounding packet
processing delay to a few microseconds, and report events
to a controller within 10 milliseconds, even in the presence
of attacks. We demonstrate these properties using an implementation
of Trumpet, and also show that it allows operators
to describe new network events such as detecting correlated
bursts and loss, identifying the root cause of transient congestion,
and detecting short-term anomalies at the scale of a data
center tenant.

Source: http://www.cs.yale.edu/homes/yu-minlan/writeup/sigcomm16.pdf

PathNet: Evolution Channels Gradient Descent in Super Neural Networks

For artificial general intelligence (AGI) it would be efficient
if multiple users trained the same giant neural network, permitting
parameter reuse, without catastrophic forgetting.
PathNet is a first step in this direction. It is a neural network
algorithm that uses agents embedded in the neural network
whose task is to discover which parts of the network to
re-use for new tasks. Agents are pathways (views) through
the network which determine the subset of parameters that
are used and updated by the forwards and backwards passes
of the backpropogation algorithm. During learning, a tournament
selection genetic algorithm is used to select pathways
through the neural network for replication and mutation.
Pathway fitness is the performance of that pathway
measured according to a cost function. We demonstrate
successful transfer learning; fixing the parameters along a
path learned on task A and re-evolving a new population
of paths for task B, allows task B to be learned faster than
it could be learned from scratch or after fine-tuning. Paths
evolved on task B re-use parts of the optimal path evolved
on task A. Positive transfer was demonstrated for binary
MNIST, CIFAR, and SVHN supervised learning classification
tasks, and a set of Atari and Labyrinth reinforcement
learning tasks, suggesting PathNets have general applicability
for neural network training. Finally, PathNet also significantly
improves the robustness to hyperparameter choices
of a parallel asynchronous reinforcement learning algorithm
(A3C).

Source: https://arxiv.org/pdf/1701.08734.pdf

The Abuse Sharing Economy: Understanding the Limits of Threat Exchanges

The underground commoditization of compromised hosts suggests a tacit capability where miscreants leverage the same machine—subscribed by multiple criminal ventures—to simultaneously profit from spam, fake account registration, malicious hosting, and other forms of automated abuse. To expedite the detection of these commonly abusive hosts, there are now multiple industry-wide efforts that aggregate abuse reports into centralized threat exchanges. In this work, we investigate the potential benefit of global reputation tracking and the pitfalls therein. We develop our findings from a snapshot of 45 million IP addresses abusing six Google services including Gmail, YouTube, and ReCaptcha between April 7–April 21, 2015. We estimate the scale of end hosts controlled by attackers, expose underground biases that skew the abuse perspectives of individual web services, and examine the frequency that criminals re-use the same infrastructure to attack multiple, heterogeneous services. Our results indicate that an average Google service can block 14% of abusive traffic based on threats aggregated from seemingly unrelated services, though we demonstrate that outright blacklisting incurs an untenable volume of false positives.

Source: https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/45491.pdf