Página 1 dos resultados de 36 itens digitais encontrados em 0.004 segundos

## An absolutely secure QKD scheme with no detection noise, entanglement and classical communication

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

26.19%

A new quantum communication scheme is introduced which is the quantum
realization of the classical Kish-Sethuraman (KS) cipher. First the message is
bounced back with additional encryption by the Receiver and the original
encryption is removed and the message is resent by the Sender. The mechanical
analogy of this operation is using two padlocks; one by the Sender and one by
the Receiver. We show that the rotation of the polarization is an operator
which satisfies the conditions required for the KS encryption operators
provided single photons are communicated. The new method is not only simple but
has several advantages. The Evasdropper extracts zero information even if she
executes a quantum measurement on the state. The communication can be done by
two publicly agreed orthogonal states. Therefore, there is no inherent
detection noise. No classical channel and no entangled states are required for
the communication.; Comment: 7 pages

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## On the Shannon cipher system with a capacity-limited key-distribution channel

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 05/05/2005

Relevância na Pesquisa

26.29%

We consider the Shannon cipher system in a setting where the secret key is
delivered to the legitimate receiver via a channel with limited capacity. For
this setting, we characterize the achievable region in the space of three
figures of merit: the security (measured in terms of the equivocation), the
compressibility of the cryptogram, and the distortion associated with the
reconstruction of the plaintext source. Although lossy reconstruction of the
plaintext does not rule out the option that the (noisy) decryption key would
differ, to a certain extent, from the encryption key, we show, nevertheless,
that the best strategy is to strive for perfect match between the two keys, by
applying reliable channel coding to the key bits, and to control the distortion
solely via rate-distortion coding of the plaintext source before the
encryption. In this sense, our result has a flavor similar to that of the
classical source-channel separation theorem. Some variations and extensions of
this model are discussed as well.; Comment: 15 pages, 1 figure

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## Multilayer Perceptron Guided Key Generation Through Mutation with Recursive Replacement in Wireless Communication (MLPKG)

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 11/08/2012

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16.51%

In this paper, a multilayer perceptron guided key generation for
encryption/decryption (MLPKG) has been proposed through recursive replacement
using mutated character code generation for wireless communication of
data/information. Multilayer perceptron transmitting systems at both ends
accept an identical input vector, generate an output bit and the network are
trained based on the output bit which is used to form a protected variable
length secret-key. For each session, different hidden layer of multilayer
neural network is selected randomly and weights or hidden units of this
selected hidden layer help to form a secret session key. The plain text is
encrypted using mutated character code table. Intermediate cipher text is yet
again encrypted through recursive replacement technique to from next
intermediate encrypted text which is again encrypted to form the final cipher
text through chaining, cascaded xoring of multilayer perceptron generated
session key. If size of the final block of intermediate cipher text is less
than the size of the key then this block is kept unaltered. Receiver will use
identical multilayer perceptron generated session key for performing
deciphering process for getting the recursive replacement encrypted cipher text
and then mutated character code table is used for decoding. Parametric tests
have been done and results are compared in terms of Chi-Square test...

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## A Cryptosystem Based on Hilbert Matrix using Cipher Block Chaining Mode

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 07/10/2011

Relevância na Pesquisa

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#Computer Science - Cryptography and Security#Computer Science - Networking and Internet Architecture

Cryptography is the science of using mathematics to encrypt and decrypt data.
Cryptography enables you to store sensitive information or transmit it across
insecure networks so that it cannot be read by anyone except the intended
recipient. While cryptography is the science of securing data, cryptanalysis is
the science of analyzing and breaking secure communication. Classical
cryptanalysis involves an interesting combination of analytical reasoning,
application of mathematical tools and pattern finding. The objectives of the
proposed work are to propose a new cryptographic method based on the special
matrix called the Hilbert matrix for authentication and confidentiality and to
propose a model for confidentiality and authentication using a combination of
symmetric and public cryptosystems. Further, it is extended to shared key
cryptosystems with the concept of digital enveloping using a session key. In
the present work an algorithm for shared key encryption is developed using
Hilbert matrix cryptosystem. In this the block chaining modes of operation have
been used to tackle the issues of confusion and diffusion.; Comment: six pages; International Journal of Mathematics Trends and
Technology- July to Aug Issue 2011

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## Variable-length Hill Cipher with MDS Key Matrix

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 06/10/2012

Relevância na Pesquisa

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The Hill Cipher is a classical symmetric cipher which breaks plaintext into
blocks of size m and then multiplies each block by an m by m key matrix to
yield ciphertext. However, it is well known that the Hill cipher succumbs to
cryptanalysis relatively easily. As a result, there have been efforts to
strengthen the cipher through the use of various techniques e.g. permuting rows
and columns of the key matrix to encrypt each plaintext vector with a new key
matrix. In this paper, we strengthen the security of the Hill cipher against a
known-plaintext attack by encrypting each plaintext matrix by a variable-length
key matrix obtained from a Maximum Distance Separable (MDS) master key matrix.

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## Enhancing the security of caesar cipher substitution method using a randomized approach for more secure communication

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 17/12/2015

Relevância na Pesquisa

26.82%

Caesar cipher is an ancient, elementary method of encrypting plain text
message to protect it from adversaries. However, with the advent of powerful
computers there is a need for increasing the complexity of such algorithms. In
this paper, we contribute in the area of classical cryptography by providing a
modified approach and expanded version for Caesar cipher using knowledge of
mathematics and computer science. To increase the strength of this classical
encryption technique we use the concepts of affine ciphers, transposition
ciphers and randomized substitution techniques to create a cipher text which is
nearly impossible to decode. We also increase the domain of characters which
Caesar cipher Algorithm can encrypt by including all ASCII and extended ASCII
characters in addition to alphabets. A complex key generation technique which
generates two keys from a single key is used to provide enhanced security. We
aim to propose a modified version of Caesar cipher substitution technique which
can overcome all the limitations faced by classical Caesar Cipher.; Comment: 6 pages, 7 figures

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## Long Response to Scheuer-Yariv: "A Classical Key-Distribution System based on Johnson (like) noise - How Secure?", physics/0601022

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

26.02%

This is the longer (partially unpublished) version of response; the shorter
version (http://arxiv.org/abs/physics/0605013) is published in Physics Letters
A. We point out that the claims in the comment-paper of Scheuer and Yariv are
either irrelevant or incorrect. We first clarify what the security of a
physically secure layer means. The idealized Kirchoff-loop-Johnson-like-noise
(KLJN) scheme is totally secure therefore it is more secure than idealized
quantum communication schemes which can never be totally secure because of the
inherent noise processes in those communication schemes and the statistical
nature of eavesdropper detection based on error statistics. On the other hand,
with sufficient resources, a practical/non-ideal realization of the KLJN cipher
can arbitrarily approach the idealized limit and outperform even the idealized
quantum communicator schemes because the non-ideality-effects are determined
and controlled by the design. The cable resistance issue analyzed by Scheuer
and Yariv is a good example for that because the eavesdropper has insufficient
time window to build a sufficient statistics and the actual information leak
can be designed. We show that Scheuer's and Yariv's numerical result of 1%
voltage drop supports higher security than that of quantum communicators.
Moreover...

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## Perfectly secure cipher system

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 04/09/2000

Relevância na Pesquisa

26.29%

We present a perfectly secure cipher system based on the concept of fake bits
which has never been used in either classical or quantum cryptography.; Comment: Tex, 6 pages

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## Quantum stream cipher based on optical communications

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 08/07/2004

Relevância na Pesquisa

26.43%

In 2000, an attractive new quantum cryptography was discovered by H.P.Yuen
based on quantum communication theory. It is applicable to direct encryption,
for example quantum stream cipher based on Yuen protocol(Y-00), with high
speeds and for long distance by sophisticated optical devices which can work
under the average photon number per signal light pulse:$ = 1000 \sim 10000$.
In addition, it may provide information-theoretic security against known/chosen
plaintext attack, which has no classical analogue. That is, one can provide
secure communication, even the system has $H(K) << H(X)$.
In this paper, first, we give a brief review on the general logic of Yuen's
theory. Then, we show concrete security analysis of quantum stream cipher to
quantum individual measurement attacks. Especially by showing the analysis of
Lo-Ko known plaintext attack, the feature of Y-00 is clarified. In addition, we
give a simple experimental result on the advantage distillation by scheme
consisting of intensity modulation/direct detection optical communication.; Comment: SPIR. Proceeding-5551,2004

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## A quantum symmetric key cipher(Y-00) and key generation (Quantum stream cipher-Part II)

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 01/10/2004

Relevância na Pesquisa

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What obstructs the realization of useful quantum cryptography is single
photon scheme, or entanglement which is not applicable to the current
infrastructure of optical communication network. We are concerned with the
following question: Can we realize the information theoretically secure
symmetric key cipher under "the finite secret key" based on quantum-optical
communications? A role of quantum information theory is to give an answer for
such a question. As an answer for the question, a new quantum cryptography was
proposed by H.P.Yuen, which can realize a secure symmetric key cipher with high
speeds(Gbps) and for long distance(1000 Km). Although some researchers claim
that Yuen protocol(Y-00) is equivalent to the classical cryptography, they are
all mistaken. Indeed it has no classical analogue, and also provides a
generalization even in the conventional cryptography.
At present, it is proved that a basic model of Y-00 has at least the security
such as $H(X|Y_E)=H(K|Y_E)=H(K)$, $H(K|Y_E,X)\sim 0$ under the average photon
number per signal light pulse:$ \sim 10000$. Towards our final goal, in this
paper, we clarify a role of classical randomness(secret key) and quantum
randomness in Y-00, and give a rigorous quantum mechanical interpretation of
the security...

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## Physical-layer encryption on the public internet: a stochastic approach to the Kish-Sethuraman cipher

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 18/06/2013

Relevância na Pesquisa

26.02%

While information-theoretic security is often associated with the one-time
pad and quantum key distribution, noisy transport media leave room for
classical techniques and even covert operation. Transit times across the public
internet exhibit a degree of randomness, and cannot be determined noiselessly
by an eavesdropper. We demonstrate the use of these measurements for
information-theoretically secure communication over the public internet.; Comment: 7 pages, 3 figures, to be presented at HotPI-2013

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## A Secure Variant of the Hill Cipher

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

26.51%

The Hill cipher is a classical symmetric encryption algorithm that succumbs
to the know-plaintext attack. Although its vulnerability to cryptanalysis has
rendered it unusable in practice, it still serves an important pedagogical role
in cryptology and linear algebra. In this paper, a variant of the Hill cipher
is introduced that makes the Hill cipher secure while it retains the
efficiency. The proposed scheme includes a ciphering core for which a
cryptographic protocol is introduced.; Comment: 4 Pages, 4 Figures

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## Quantum Vernam Cipher

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

26.75%

We discuss aspects of secure quantum communication by proposing and analyzing
a quantum analog of the Vernam cipher (one-time-pad). The quantum Vernam cipher
uses entanglement as the key to encrypt quantum information sent through an
insecure quantum channel. First, in sharp contrast with the classical Vernam
cipher, the quantum key can be recycled securely. We show that key recycling is
intrinsic to the quantum cipher-text, rather than using entanglement as the
key. Second, the scheme detects and corrects for arbitrary transmission errors,
and it does so using only local operations and classical communication (LOCC)
between the sender and the receiver. The application to quantum message
authentication is discussed. Quantum secret sharing schemes with similar
properties are characterized. We also discuss two general issues, the relation
between secret communication and secret sharing, the classification of secure
communication protocols.; Comment: stronger security proof for recycling classical keys

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## A Hybrid Cryptosystem Based On Vigenere Cipher and Columnar Transposition Cipher

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 29/07/2013

Relevância na Pesquisa

26.43%

Privacy is one of the key issues addressed by information Security. Through
cryptographic encryption methods, one can prevent a third party from
understanding transmitted raw data over unsecured channel during signal
transmission. The cryptographic methods for enhancing the security of digital
contents have gained high significance in the current era. Breach of security
and misuse of confidential information that has been intercepted by
unauthorized parties are key problems that information security tries to solve.
This paper sets out to contribute to the general body of knowledge in the area
of classical cryptography by develop- ing a new hybrid way of encryption of
plaintext. The cryptosystem performs its encryption by encrypting the plaintext
using columnar transposition cipher and further using the ciphertext to encrypt
the plaintext again using Vigen\`ere ci- pher. At the end, cryptanalysis was
performed on the ciphertext. The implementation will be done using java
program- ming.; Comment: 7 pages. International Journal of Advanced Technology & Engineering
Research Volume 3 Issue 1 (IJATER), 2013

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## A New Type of Cipher

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

26.43%

We will define a new type of cipher that doesn't use neither an easy to
calcualate and hard to invert matematical function like RSA nor a classical
mono or polyalphabetic cipher.

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## Totally secure classical networks with multipoint telecloning (teleportation) of classical bits through loops with Johnson-like noise

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

26.54%

First, we show a new inexpensive defense against intruders and the
man-in-the-middle attack in the Kirchhoff's-loop-Johnson-like-noise (KLJN)
cipher. Then instead of point-to-point communication, we propose a high
efficiency, secure network. The (in the idealistic case totally secure)
classical network is based on an improved version of the KLJN cipher. The
network consists of two parallel networks: i) a chain-like network of securely
communicating, electrically isolated Kirchhoff-loops with Johnson-like noise
and driven by a specific switching process of the resistances; ii) and a
regular non-secure data network with a Coordinator-server. If the classical
network is fast enough, the chain-like network of N communicators can generate
and share an N bit long secret key within a single clock period of the ciphers
and that implies a significant speed-up compared to the point-to-point key
exchanges used by quantum communication or RSA-like key exchange methods. This
is a teleportation-type multiple telecloning of the classical information bit
because the information transfer can take place without the actual presence of
the information bit at the intermediate points of the network. With similar
quantum schemes the telecloning of classical bits via quantum communicator
networks without telecloning the quantum states is also possible.; Comment: Quantum-based network application added. 13 pages

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## Response to Scheuer-Yariv: "A Classical Key-Distribution System based on Johnson (like) noise -How Secure?"

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

26.02%

We point out that the claims in the comment-paper of Scheuer and Yariv are
either irrelevant or incorrect. The idealized Kirchoff-loop-Johnson-like-noise
(KLJN) scheme is totally secure therefore it is more secure than idealized
quantum communication schemes which can never be totally secure because of the
inherent noise processes in those communication schemes and the statistical
nature of eavesdropper detection based on error statistics. On the other hand,
with sufficient resources, a practical/non-ideal realization of the KLJN cipher
can arbitrarily approach the idealized limit and outperform even the idealized
quantum communicator schemes because the non-ideality-effects are determined
and controlled by the design. The cable resistance issue analyzed by Scheuer
and Yariv is a good example for that because the eavesdropper has insufficient
time window to build a sufficient statistics and the actual information leak
can be designed. We show that Scheuer's and Yariv's numerical result of 1%
voltage drop supports higher security than that of quantum communicators.
Moreover, choosing thicker or shorter wires can arbitrarily reduce this voltage
drop further; the same conclusion holds even according to the equations of
Scheuer and Yariv.; Comment: Publication data added

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## Spiking Neurons with ASNN Based-Methods for the Neural Block Cipher

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 28/08/2010

Relevância na Pesquisa

26.57%

Problem statement: This paper examines Artificial Spiking Neural Network
(ASNN) which inter-connects group of artificial neurons that uses a
mathematical model with the aid of block cipher. The aim of undertaken this
research is to come up with a block cipher where by the keys are randomly
generated by ASNN which can then have any variable block length. This will show
the private key is kept and do not have to be exchange to the other side of the
communication channel so it present a more secure procedure of key scheduling.
The process enables for a faster change in encryption keys and a network level
encryption to be implemented at a high speed without the headache of
factorization. Approach: The block cipher is converted in public cryptosystem
and had a low level of vulnerability to attack from brute, and moreover can
able to defend against linear attacks since the Artificial Neural Networks
(ANN) architecture convey non-linearity to the encryption/decryption
procedures. Result: In this paper is present to use the Spiking Neural Networks
(SNNs) with spiking neurons as its basic unit. The timing for the SNNs is
considered and the output is encoded in 1's and 0's depending on the occurrence
or not occurrence of spikes as well as the spiking neural networks use a sign
function as activation function...

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## The double-padlock problem: is secure classical information transmission possible without key exchange?

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

36.19%

The idealized Kish-Sethuraman (KS) cipher is theoretically known to offer
perfect security through a classical information channel. However, realization
of the protocol is hitherto an open problem, as the required mathematical
operators have not been identified in the previous literature. A mechanical
analogy of this protocol can be seen as sending a message in a box using two
padlocks; one locked by the Sender and the other locked by the Receiver, so
that theoretically the message remains secure at all times. We seek a
mathematical representation of this process, considering that it would be very
unusual if there was a physical process with no mathematical description and
indeed we find a solution within a four dimensional Clifford algebra. The
significance of finding a mathematical description that describes the protocol,
is that it is a possible step toward a physical realization having benefits in
increased security with reduced complexity.; Comment: 4 pages

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## Genetic algorithms in cryptography; GAs in cryptography

Fonte: Rochester Instituto de Tecnologia
Publicador: Rochester Instituto de Tecnologia

Tipo: Tese de Doutorado
Formato: 539124 bytes; 1220359 bytes; 1220123 bytes; 1003907 bytes; 19284 bytes; 537 bytes; 539 bytes; 1727 bytes; 19168 bytes; 19630 bytes; 19149 bytes; 21868 bytes; 21147 bytes; 23856 bytes; 31031 bytes; 6479 bytes; 6943 bytes; 20517 bytes; 5083 bytes; 6691 byte

EN_US

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#attack comparison#classical cipher#cryptanalysis#cryptography#cryptology#genetic algorithm#QA268 .D45 2004#Cryptography--Research#Genetic algorithms--Research#Data encryption (Computer science)--Research

Genetic algorithms (GAs) are a class of optimization algorithms. GAs attempt to solve
problems through modeling a simplified version of genetic processes. There are many
problems for which a GA approach is useful. It is, however, undetermined if cryptanalysis
is such a problem.
Therefore, this work explores the use of GAs in cryptography. Both traditional cryptanalysis
and GA-based methods are implemented in software. The results are then compared
using the metrics of elapsed time and percentage of successful decryptions. A determination
is made for each cipher under consideration as to the validity of the GA-based
approaches found in the literature. In general, these GA-based approaches are typical of
the field.
Of the genetic algorithm attacks found in the literature, totaling twelve, seven were
re-implemented. Of these seven, only three achieved any success. The successful attacks
were those on the transposition and permutation ciphers by Matthews [20], Clark [4], and
Gr¨undlingh and Van Vuuren [13], respectively. These attacks were further investigated in
an attempt to improve or extend their success. Unfortunately, this attempt was unsuccessful,
as was the attempt to apply the Clark [4] attack to the monoalphabetic substitution cipher
and achieve the same or indeed any level of success.
Overall...

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