1,359 research outputs found
Quantum Differential Cryptanalysis
In this paper, we propose a quantum version of the differential cryptanalysis
which offers a quadratic speedup over the existing classical one and show the
quantum circuit implementing it. The quantum differential cryptanalysis is
based on the quantum minimum/maximum-finding algorithm, where the values to be
compared and filtered are obtained by calling the quantum counting algorithm.
Any cipher which is vulnerable to the classical differential cryptanalysis
based on counting procedures can be cracked more quickly under this quantum
differential attack.Comment: 9 pages, 3 figure
Quantum differential cryptanalysis to the block ciphers
Differential cryptanalysis is one of the most popular methods in attacking
block ciphers. However, there still some limitations in traditional
differential cryptanalysis. On the other hand, researches of quantum algorithms
have made great progress nowadays. This paper proposes two methods to apply
quantum algorithms in differential cryptanalysis, and analysis their
efficiencies and success probabilities. One method is using quantum algorithm
in the high probability differential finding period for every S-Box. The second
method is taking the encryption as a whole, using quantum algorithm in this
process.Comment: 11 pages, no figure
Using Bernstein-Vazirani Algorithm to Attack Block Ciphers
In this paper, we study applications of Bernstein-Vazirani algorithm and
present several new methods to attack block ciphers. Specifically, we first
present a quantum algorithm for finding the linear structures of a function.
Based on it, we propose new quantum distinguishers for the 3-round Feistel
scheme and a new quantum algorithm to recover partial key of the Even-Mansour
construction. Afterwards, by observing that the linear structures of a
encryption function are actually high probability differentials of it, we apply
our algorithm to differential analysis and impossible differential
cryptanalysis respectively. We also propose a new kind of differential
cryptanalysis, called quantum small probability differential cryptanalysis,
based on the fact that the linear structures found by our algorithm are also
the linear structure of each component function. To our knowledge, no similar
method was proposed before. The efficiency and success probability of all
attacks are analyzed rigorously. Since our algorithm treats the encryption
function as a whole, it avoid the disadvantage of traditional differential
cryptanalysis that it is difficult to extending the differential path.Comment: 23 pages, 1 figure
Quantum Miss-in-the-Middle Attack
We apply Simon's algorithm to the miss-in-the-middle technique and propose a
quantum algorithm for finding impossible differentials of a general block
cipher. We prove that, under certain assumption on the block cipher, the
differentials output by the quantum algorithm are key-independent impossible
differentials of the block cipher with a overwhelming probability. Moreover, we
demonstrate that if the traditional miss-in-the-middle attack works for the
block cipher, the proposed quantum algorithm will always work as well. By
contrast, the quantum version of miss-in-the-middle technique proposed in this
paper to some extent compensates for the disadvantages of traditional
miss-in-the-middle technique that the successful probability decreases greatly
with the increase of the number of rounds.Comment: 17 pages, 0 figure
Universal chosen-ciphertext attack for a family of image encryption schemes
During the past decades, there is a great popularity employing nonlinear
dynamics and permutation-substitution architecture for image encryption. There
are three primary procedures in such encryption schemes, the key schedule
module for producing encryption factors, permutation for image scrambling and
substitution for pixel modification. Under the assumption of chosen-ciphertext
attack, we evaluate the security of a class of image ciphers which adopts
pixel-level permutation and modular addition for substitution. It is
mathematically revealed that the mapping from differentials of ciphertexts to
those of plaintexts are linear and has nothing to do with the key schedules,
permutation techniques and encryption rounds. Moreover, a universal
chosen-ciphertext attack is proposed and validated. Experimental results
demonstrate that the plaintexts can be directly reconstructed without any
security key or encryption elements. Related cryptographic discussions are also
given.Comment: 12 page
A New DNA-Based Approach of Generating Key-dependent ShiftRows Transformation
The use of key-dependent shiftRows can be considered as one of the applied
methods for altering the quality of a cryptographic algorithm. This article
describes one approach for changing the ShiftRows transformation employed in
the algorithm AES. The approach employs methods inspired from DNA processes and
structure which depended on the key while the parameters of the created new
ShiftRows have characteristics identical to those of the original algorithm AES
in addition to increase its resistance against attacks. The proposed new
ShiftRows were tested for coefficient correlation for dynamic and static
independence between the input and output. The NIST Test Suite tests were used
to test the randomness for the block cipher that used the new transformation
Quasigroups in cryptology
We give a review of some known published applications of quasigroups in
cryptology.Comment: 31 page
When an attacker meets a cipher-image in 2018: A Year in Review
This paper aims to review the encountered technical contradictions when an
attacker meets the cipher-images encrypted by the image encryption schemes
(algorithms) proposed in 2018 from the viewpoint of an image cryptanalyst. The
most representative works among them are selected and classified according to
their essential structures. Almost all image cryptanalysis works published in
2018 are surveyed due to their small number. The challenging problems on design
and analysis of image encryption schemes are summarized to receive the
attentions of both designers and attackers (cryptanalysts) of image encryption
schemes, which may promote solving scenario-oriented image security problems
with new technologies.Comment: 12 page
Security Protocols in a Nutshell
Security protocols are building blocks in secure communications. They deploy
some security mechanisms to provide certain security services. Security
protocols are considered abstract when analyzed, but they can have extra
vulnerabilities when implemented. This manuscript provides a holistic study on
security protocols. It reviews foundations of security protocols, taxonomy of
attacks on security protocols and their implementations, and different methods
and models for security analysis of protocols. Specifically, it clarifies
differences between information-theoretic and computational security, and
computational and symbolic models. Furthermore, a survey on computational
security models for authenticated key exchange (AKE) and password-authenticated
key exchange (PAKE) protocols, as the most important and well-studied type of
security protocols, is provided.Comment: Based on the introduction part of the author's dissertatio
On the security of a class of diffusion mechanisms for image encryption
The need for fast and strong image cryptosystems motivates researchers to
develop new techniques to apply traditional cryptographic primitives in order
to exploit the intrinsic features of digital images. One of the most popular
and mature technique is the use of complex ynamic phenomena, including chaotic
orbits and quantum walks, to generate the required key stream. In this paper,
under the assumption of plaintext attacks we investigate the security of a
classic diffusion mechanism (and of its variants) used as the core
cryptographic rimitive in some image cryptosystems based on the aforementioned
complex dynamic phenomena. We have theoretically found that regardless of the
key schedule process, the data complexity for recovering each element of the
equivalent secret key from these diffusion mechanisms is only O(1). The
proposed analysis is validated by means of numerical examples. Some additional
cryptographic applications of our work are also discussed.Comment: 16 pages, 7 figure
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