2,086 research outputs found
Implementation of the Array-based Approach for the Evaluation of Randomness of the Advanced Encryption Standard (AES)
Randomness is critical when it comes to cryptography. When a cryptographic system has randomness in it, it is impossible to decrypt the codes and break the system. To evaluate a cryptographic function’s randomness, many statistical tests were developed such as: Diehard and ENT, but these tests are not well suited for block ciphers. CryptoStat is the best statistical test suite to test the randomness of the Advanced Encryption Standard or AES, which is a block cipher established by NIST, the National Institute of Standard and Technology. An array based approach is also used to apply the CryptoStat test suite on AES
A fast and light stream cipher for smartphones
We present a stream cipher based on a chaotic dynamical system. Using a
chaotic trajectory sampled under certain rules in order to avoid any attempt to
reconstruct the original one, we create a binary pseudo-random keystream that
can only be exactly reproduced by someone that has fully knowledge of the
communication system parameters formed by a transmitter and a receiver and
sharing the same initial conditions. The plaintext is XORed with the keystream
creating the ciphertext, the encrypted message. This keystream passes the NISTs
randomness test and has been implemented in a videoconference App for
smartphones, in order to show the fast and light nature of the proposed
encryption system
A Novel Latin Square Image Cipher
In this paper, we introduce a symmetric-key Latin square image cipher (LSIC)
for grayscale and color images. Our contributions to the image encryption
community include 1) we develop new Latin square image encryption primitives
including Latin Square Whitening, Latin Square S-box and Latin Square P-box ;
2) we provide a new way of integrating probabilistic encryption in image
encryption by embedding random noise in the least significant image bit-plane;
and 3) we construct LSIC with these Latin square image encryption primitives
all on one keyed Latin square in a new loom-like substitution-permutation
network. Consequently, the proposed LSIC achieve many desired properties of a
secure cipher including a large key space, high key sensitivities, uniformly
distributed ciphertext, excellent confusion and diffusion properties,
semantically secure, and robustness against channel noise. Theoretical analysis
show that the LSIC has good resistance to many attack models including
brute-force attacks, ciphertext-only attacks, known-plaintext attacks and
chosen-plaintext attacks. Experimental analysis under extensive simulation
results using the complete USC-SIPI Miscellaneous image dataset demonstrate
that LSIC outperforms or reach state of the art suggested by many peer
algorithms. All these analysis and results demonstrate that the LSIC is very
suitable for digital image encryption. Finally, we open source the LSIC MATLAB
code under webpage https://sites.google.com/site/tuftsyuewu/source-code.Comment: 26 pages, 17 figures, and 7 table
Comparison analysis of stream cipher algorithms for digital communication
The broadcast nature of radio communication such as in the HF (High Frequency) spectrum exposes the transmitted information to unauthorized third parties. Confidentiality is ensured by employing cipher system. For bulk transmission of data, stream ciphers are ideal choices over block ciphers due to faster implementation speed and not introducing error propagation. The stream cipher algorithms evaluated are based on the linear feedback shift register (LFSR) with nonlinear combining function. By using a common key length and worst case conditions, the strength of several stream cipher algorithms are evaluated using statistical tests, correlation attack, linear complexity profile and nonstandard test. The best algorithm is the one that exceeds all of the tests
Deciphering a novel image cipher based on mixed transformed Logistic maps
Since John von Neumann suggested utilizing Logistic map as a random number
generator in 1947, a great number of encryption schemes based on Logistic map
and/or its variants have been proposed. This paper re-evaluates the security of
an image cipher based on transformed logistic maps and proves that the image
cipher can be deciphered efficiently under two different conditions: 1) two
pairs of known plain-images and the corresponding cipher-images with
computational complexity of ; 2) two pairs of chosen plain-images
and the corresponding cipher-images with computational complexity of ,
where is the number of pixels in the plain-image. In contrast, the required
condition in the previous deciphering method is eighty-seven pairs of chosen
plain-images and the corresponding cipher-images with computational complexity
of . In addition, three other security flaws existing in most
Logistic-map-based ciphers are also reported.Comment: 10 pages, 2 figure
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