1,336 research outputs found
Encryption of Covert Information into Multiple Statistical Distributions
A novel strategy to encrypt covert information (code) via unitary projections
into the null spaces of ill-conditioned eigenstructures of multiple host
statistical distributions, inferred from incomplete constraints, is presented.
The host pdf's are inferred using the maximum entropy principle. The projection
of the covert information is dependent upon the pdf's of the host statistical
distributions. The security of the encryption/decryption strategy is based on
the extreme instability of the encoding process. A self-consistent procedure to
derive keys for both symmetric and asymmetric cryptography is presented. The
advantages of using a multiple pdf model to achieve encryption of covert
information are briefly highlighted. Numerical simulations exemplify the
efficacy of the model.Comment: 18 pages, 4 figures. Three sentences expanded to emphasize detail.
Typos correcte
Blindspot: Indistinguishable Anonymous Communications
Communication anonymity is a key requirement for individuals under targeted
surveillance. Practical anonymous communications also require
indistinguishability - an adversary should be unable to distinguish between
anonymised and non-anonymised traffic for a given user. We propose Blindspot, a
design for high-latency anonymous communications that offers
indistinguishability and unobservability under a (qualified) global active
adversary. Blindspot creates anonymous routes between sender-receiver pairs by
subliminally encoding messages within the pre-existing communication behaviour
of users within a social network. Specifically, the organic image sharing
behaviour of users. Thus channel bandwidth depends on the intensity of image
sharing behaviour of users along a route. A major challenge we successfully
overcome is that routing must be accomplished in the face of significant
restrictions - channel bandwidth is stochastic. We show that conventional
social network routing strategies do not work. To solve this problem, we
propose a novel routing algorithm. We evaluate Blindspot using a real-world
dataset. We find that it delivers reasonable results for applications requiring
low-volume unobservable communication.Comment: 13 Page
Audio steganography with AES for real-time covert Voice over Internet Protocol communications
As a popular real-time service on the Internet, Voice over Internet Protocol (VoIP) communication attracts more and more attention from the researchers in the information security field. In this study, we proposed a VoIP steganographic algorithm with variable embedding capacities, incorporating AES and key distribution, to realize a real-time covert VoIP communication. The covert communication system was implemented by embedding a secret message encrypted with symmetric cryptography AES-128 into audio signals encoded by PCM codec. At the beginning of each VoIP call, a symmetric session key (SK) was assigned to the receiver with a Session Initiation Protocol-based authentication method. The secret message was encrypted and then embedded into audio packets with different embedding algorithms before sending them, so as to meet the real-time requirements of VoIP communications. For each audio packet, the embedding capacity was calculated according to the specific embedding algorithm used. The encryption and embedding processes were almost synchronized. The time cost of encryption was so short that it could be ignored. As a result of AES-based steganography, observers could not detect the hidden message using simple statistical analysis. At the receiving end, the corresponding algorithm along with the SK was employed to retrieve the original secret message from the audio signals. Performance evaluation with state-of-the-art network equipment and security tests conducted using the Mann-Whitney-Wilcoxon method indicated that the proposed steganographic algorithm is secure, effective, and robust
Revisiting Deniability in Quantum Key Exchange via Covert Communication and Entanglement Distillation
We revisit the notion of deniability in quantum key exchange (QKE), a topic
that remains largely unexplored. In the only work on this subject by Donald
Beaver, it is argued that QKE is not necessarily deniable due to an
eavesdropping attack that limits key equivocation. We provide more insight into
the nature of this attack and how it extends to other constructions such as QKE
obtained from uncloneable encryption. We then adopt the framework for quantum
authenticated key exchange, developed by Mosca et al., and extend it to
introduce the notion of coercer-deniable QKE, formalized in terms of the
indistinguishability of real and fake coercer views. Next, we apply results
from a recent work by Arrazola and Scarani on covert quantum communication to
establish a connection between covert QKE and deniability. We propose DC-QKE, a
simple deniable covert QKE protocol, and prove its deniability via a reduction
to the security of covert QKE. Finally, we consider how entanglement
distillation can be used to enable information-theoretically deniable protocols
for QKE and tasks beyond key exchange.Comment: 16 pages, published in the proceedings of NordSec 201
Using Facebook for Image Steganography
Because Facebook is available on hundreds of millions of desktop and mobile
computing platforms around the world and because it is available on many
different kinds of platforms (from desktops and laptops running Windows, Unix,
or OS X to hand held devices running iOS, Android, or Windows Phone), it would
seem to be the perfect place to conduct steganography. On Facebook, information
hidden in image files will be further obscured within the millions of pictures
and other images posted and transmitted daily. Facebook is known to alter and
compress uploaded images so they use minimum space and bandwidth when displayed
on Facebook pages. The compression process generally disrupts attempts to use
Facebook for image steganography. This paper explores a method to minimize the
disruption so JPEG images can be used as steganography carriers on Facebook.Comment: 6 pages, 4 figures, 2 tables. Accepted to Fourth International
Workshop on Cyber Crime (IWCC 2015), co-located with 10th International
Conference on Availability, Reliability and Security (ARES 2015), Toulouse,
France, 24-28 August 201
Covert Channels Within IRC
The exploration of advanced information hiding techniques is important to understand and defend against illicit data extractions over networks. Many techniques have been developed to covertly transmit data over networks, each differing in their capabilities, methods, and levels of complexity. This research introduces a new class of information hiding techniques for use over Internet Relay Chat (IRC), called the Variable Advanced Network IRC Stealth Handler (VANISH) system. Three methods for concealing information are developed under this framework to suit the needs of an attacker. These methods are referred to as the Throughput, Stealth, and Baseline scenarios. Each is designed for a specific purpose: to maximize channel capacity, minimize shape-based detectability, or provide a baseline for comparison using established techniques applied to IRC. The effectiveness of these scenarios is empirically tested using public IRC servers in Chicago, Illinois and Amsterdam, Netherlands. The Throughput method exfiltrates covert data at nearly 800 bits per second (bps) compared to 18 bps with the Baseline method and 0.13 bps for the Stealth method. The Stealth method uses Reed-Solomon forward error correction to reduce bit errors from 3.1% to nearly 0% with minimal additional overhead. The Stealth method also successfully evades shape-based detection tests but is vulnerable to regularity-based tests
Using Markov Models and Statistics to Learn, Extract, Fuse, and Detect Patterns in Raw Data
Many systems are partially stochastic in nature. We have derived data driven
approaches for extracting stochastic state machines (Markov models) directly
from observed data. This chapter provides an overview of our approach with
numerous practical applications. We have used this approach for inferring
shipping patterns, exploiting computer system side-channel information, and
detecting botnet activities. For contrast, we include a related data-driven
statistical inferencing approach that detects and localizes radiation sources.Comment: Accepted by 2017 International Symposium on Sensor Networks, Systems
and Securit
Secure covert communications over streaming media using dynamic steganography
Streaming technologies such as VoIP are widely embedded into commercial and industrial applications, so it is imperative to address data security issues before the problems get really serious. This thesis describes a theoretical and experimental investigation of secure covert communications over streaming media using dynamic steganography. A covert VoIP communications system was developed in C++ to enable the implementation of the work being carried out.
A new information theoretical model of secure covert communications over streaming media was constructed to depict the security scenarios in streaming media-based steganographic systems with passive attacks. The model involves a stochastic process that models an information source for covert VoIP communications and the theory of hypothesis testing that analyses the adversaryâs detection performance.
The potential of hardware-based true random key generation and chaotic interval selection for innovative applications in covert VoIP communications was explored. Using the read time stamp counter of CPU as an entropy source was designed to generate true random numbers as secret keys for streaming media steganography. A novel interval selection algorithm was devised to choose randomly data embedding locations in VoIP streams using random sequences generated from achaotic process.
A dynamic key updating and transmission based steganographic algorithm that includes a one-way cryptographical accumulator integrated into dynamic key exchange for covert VoIP communications, was devised to provide secure key exchange for covert communications over streaming media. The discrete logarithm problem in mathematics and steganalysis using t-test revealed the algorithm has the advantage of being the most solid method of key distribution over a public channel.
The effectiveness of the new steganographic algorithm for covert communications over streaming media was examined by means of security analysis, steganalysis using non parameter Mann-Whitney-Wilcoxon statistical testing, and performance and robustness measurements. The algorithm achieved the average data embedding rate of 800 bps, comparable to other related algorithms. The results indicated that the algorithm has no or little impact on real-time VoIP communications in terms of speech quality (< 5% change in PESQ with hidden data), signal distortion (6% change in SNR after steganography) and imperceptibility, and it is more secure and effective in addressing the security problems than other related algorithms
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