2,875 research outputs found
Applied public-key steganography
International audienceWe consider the problem of hiding information in a steganographic framework, i.e. embedding a binary message within an apparently innocuous content, in order to establish a `suspicion-free' digital communication channel. The adversary is passive as no intentional attack is foreseen. The only threat is that she discovers the presence of a hidden communication. The main goal of this article is to find if the calar Costa Scheme, a recently published embedding method exploiting side information at the encoder, is suitable for that framework. We justify its use assessing its security level with respect to the Cachin's criterion. We derive a public-key stegosystem following the ideas of R. Anderson and P. Petitcolas. This technique is eventually applied to PCM audio contents. Experimental performances are detailed in terms of bit-rate and Kullback-Leibler distance
How to Bootstrap Anonymous Communication
We ask whether it is possible to anonymously communicate a large amount of
data using only public (non-anonymous) communication together with a small
anonymous channel. We think this is a central question in the theory of
anonymous communication and to the best of our knowledge this is the first
formal study in this direction. To solve this problem, we introduce the concept
of anonymous steganography: think of a leaker Lea who wants to leak a large
document to Joe the journalist. Using anonymous steganography Lea can embed
this document in innocent looking communication on some popular website (such
as cat videos on YouTube or funny memes on 9GAG). Then Lea provides Joe with a
short key which, when applied to the entire website, recovers the document
while hiding the identity of Lea among the large number of users of the
website. Our contributions include:
- Introducing and formally defining anonymous steganography,
- A construction showing that anonymous steganography is possible (which uses
recent results in circuits obfuscation),
- A lower bound on the number of bits which are needed to bootstrap anonymous
communication.Comment: 15 page
Perfectly secure steganography: hiding information in the quantum noise of a photograph
We show that the quantum nature of light can be used to hide a secret message
within a photograph. Using this physical principle we achieve
information-theoretic secure steganography, which had remained elusive until
now. The protocol is such that the digital picture in which the secret message
is embedded is perfectly undistinguishable from an ordinary photograph. This
implies that, on a fundamental level, it is impossible to discriminate a
private communication from an exchange of photographs.Comment: 5 pages, 3 figures + appendix : 5 pages, 6 figure
Review on DNA Cryptography
Cryptography is the science that secures data and communication over the
network by applying mathematics and logic to design strong encryption methods.
In the modern era of e-business and e-commerce the protection of
confidentiality, integrity and availability (CIA triad) of stored information
as well as of transmitted data is very crucial. DNA molecules, having the
capacity to store, process and transmit information, inspires the idea of DNA
cryptography. This combination of the chemical characteristics of biological
DNA sequences and classical cryptography ensures the non-vulnerable
transmission of data. In this paper we have reviewed the present state of art
of DNA cryptography.Comment: 31 pages, 12 figures, 6 table
Perfectly Secure Steganography: Capacity, Error Exponents, and Code Constructions
An analysis of steganographic systems subject to the following perfect
undetectability condition is presented in this paper. Following embedding of
the message into the covertext, the resulting stegotext is required to have
exactly the same probability distribution as the covertext. Then no statistical
test can reliably detect the presence of the hidden message. We refer to such
steganographic schemes as perfectly secure. A few such schemes have been
proposed in recent literature, but they have vanishing rate. We prove that
communication performance can potentially be vastly improved; specifically, our
basic setup assumes independently and identically distributed (i.i.d.)
covertext, and we construct perfectly secure steganographic codes from public
watermarking codes using binning methods and randomized permutations of the
code. The permutation is a secret key shared between encoder and decoder. We
derive (positive) capacity and random-coding exponents for perfectly-secure
steganographic systems. The error exponents provide estimates of the code
length required to achieve a target low error probability. We address the
potential loss in communication performance due to the perfect-security
requirement. This loss is the same as the loss obtained under a weaker order-1
steganographic requirement that would just require matching of first-order
marginals of the covertext and stegotext distributions. Furthermore, no loss
occurs if the covertext distribution is uniform and the distortion metric is
cyclically symmetric; steganographic capacity is then achieved by randomized
linear codes. Our framework may also be useful for developing computationally
secure steganographic systems that have near-optimal communication performance.Comment: To appear in IEEE Trans. on Information Theory, June 2008; ignore
Version 2 as the file was corrupte
Transparent authentication methodology in electronic education
In the context of on-line assessment in e-learning, a problem arises when a student taking an exam may wish to cheat by handing over personal credentials to someone else to take their place in an exam, Another problem is that there is no method for signing digital content as it is being produced in a computerized environment. Our proposed solution is to digitally sign the participantâs work by embedding voice samples in the transcript paper at regular intervals. In this investigation, we have demonstrated that a transparent stenographic methodology will provide an innovative and practical solution for achieving continuous authentication in an online educational environment by successful insertion and extraction of audio digital signatures
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