Encryption with Covertext and Reordering using Permutated Table and Random Function

2021 ◽  
Author(s):  
Eka Ardhianto ◽  
Widiyanto Tri Handoko ◽  
Hari Murti ◽  
Rara Sri Artati Redjeki
Keyword(s):  
Random Function

Comment on the Security of an Order-Preserving Encryption Scheme Using Pseudo-Random Function

2016 ◽  
Vol E99.B (9) ◽  
pp. 2108-2111
Author(s):  
Minkyu KIM ◽  
Je HONG PARK ◽  
Dongyoung ROH
Keyword(s):  
Random Function ◽  
Encryption Scheme

Efficient Construction of Order-Preserving Encryption Using Pseudo Random Function

2015 ◽  
Vol E98.B (7) ◽  
pp. 1276-1283 ◽  
Author(s):  
Nam-Su JHO ◽  
Ku-Young CHANG ◽  
Do-Won HONG
Keyword(s):  
Random Function ◽  
Efficient Construction

Efficient Steganography Algorithm Based On DCT And Entropy Thresholding Technique

2018 ◽  
Vol 8 (1) ◽  
pp. 45
Author(s):  
Satvir Singh
Keyword(s):  
Relative Entropy ◽  
Experimental Work ◽  
Random Function ◽  
Signal To Noise Ratio ◽  
Binary Sequence ◽  
Threshold Value ◽  
Absolute Difference ◽  
Secret Message ◽  
Signal To Noise ◽  
Confidential Information

Steganography is the special art of hidding important and confidential information in appropriate multimedia carrier. It also restrict the detection of  hidden messages. In this paper we proposes steganographic method based on dct and entropy thresholding technique. The steganographic algorithm uses random function in order to select block of the image where the elements of the binary sequence of a secret message will be inserted. Insertion takes place at the lower frequency  AC coefficients of the  block. Before we insert the secret  message. Image under goes dc transformations after insertion of the secret message we apply inverse dc transformations. Secret message will only be inserted into a particular block if  entropy value of that particular block is greater then threshold value of the entropy and if block is selected by the random function. In  Experimental work we calculated the peak signal to noise ratio(PSNR), Absolute difference , Relative entropy. Proposed algorithm give high value of PSNR  and low value of Absolute difference which clearly indicate level of distortion in image due to insertion of secret message is reduced. Also value of  relative entropy is close to zero which clearly indicate proposed algorithm is sufficiently secure. 

scholarly journals A Novel Construction of Constrained Verifiable Random Functions

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Muhua Liu ◽  
Ping Zhang ◽  
Qingtao Wu
Keyword(s):  
Random Function ◽  
Secret Key ◽  
Bilinear Maps ◽  
Random Functions ◽  
Compute Function ◽  
Multilinear Maps ◽  
Verifiable Random Functions ◽  
Selective Security

Constrained verifiable random functions (VRFs) were introduced by Fuchsbauer. In a constrained VRF, one can drive a constrained key skS from the master secret key sk, where S is a subset of the domain. Using the constrained key skS, one can compute function values at points which are not in the set S. The security of constrained VRFs requires that the VRFs’ output should be indistinguishable from a random value in the range. They showed how to construct constrained VRFs for the bit-fixing class and the circuit constrained class based on multilinear maps. Their construction can only achieve selective security where an attacker must declare which point he will attack at the beginning of experiment. In this work, we propose a novel construction for constrained verifiable random function from bilinear maps and prove that it satisfies a new security definition which is stronger than the selective security. We call it semiadaptive security where the attacker is allowed to make the evaluation queries before it outputs the challenge point. It can immediately get that if a scheme satisfied semiadaptive security, and it must satisfy selective security.

scholarly journals $$L_2$$-norm sampling discretization and recovery of functions from RKHS with finite trace

2021 ◽  
Vol 19 (2) ◽  
Author(s):  
Moritz Moeller ◽  
Tino Ullrich
Keyword(s):  
Random Function ◽  
Additional Assumption ◽  
Main Tool ◽  
Singular Values ◽  
Rates Of Convergence ◽  
Concentration Inequality ◽  
Worst Case ◽  
Mercer Kernels ◽  
Finite Trace ◽  
Complex Valued

AbstractIn this paper we study $$L_2$$ L 2 -norm sampling discretization and sampling recovery of complex-valued functions in RKHS on $$D \subset \mathbb {R}^d$$ D ⊂ R d based on random function samples. We only assume the finite trace of the kernel (Hilbert–Schmidt embedding into $$L_2$$ L 2 ) and provide several concrete estimates with precise constants for the corresponding worst-case errors. In general, our analysis does not need any additional assumptions and also includes the case of non-Mercer kernels and also non-separable RKHS. The fail probability is controlled and decays polynomially in n, the number of samples. Under the mild additional assumption of separability we observe improved rates of convergence related to the decay of the singular values. Our main tool is a spectral norm concentration inequality for infinite complex random matrices with independent rows complementing earlier results by Rudelson, Mendelson, Pajor, Oliveira and Rauhut.

scholarly journals Dispersing Hash Functions

2000 ◽  
Vol 7 (36) ◽  
Author(s):  
Rasmus Pagh
Keyword(s):  
Lower Bounds ◽  
Random Function ◽  
Hash Functions ◽  
Expected Value ◽  
Independent Interest ◽  
Upper And Lower Bounds ◽  
Related Issue ◽  
Logarithmic Factor

A new hashing primitive is introduced: dispersing hash functions. A family<br />of hash functions F is dispersing if, for any set S of a certain size and random<br />h in F, the expected value of |S|−|h[S]| is not much larger than the expectancy<br />if h had been chosen at random from the set of all functions.<br />We give tight, up to a logarithmic factor, upper and lower bounds on the<br />size of dispersing families. Such families previously studied, for example <br />universal families, are significantly larger than the smallest dispersing families,<br />making them less suitable for derandomization. We present several applications<br /> of dispersing families to derandomization (fast element distinctness, set<br />inclusion, and static dictionary initialization). Also, a tight relationship <br />between dispersing families and extractors, which may be of independent interest,<br />is exhibited.<br />We also investigate the related issue of program size for hash functions<br />which are nearly perfect. In particular, we exhibit a dramatic increase in<br />program size for hash functions more dispersing than a random function.

A Color Image Encryption Algorithm Based on Improved DES

2015 ◽  
Vol 743 ◽  
pp. 379-384 ◽  
Author(s):  
Zhang Li Lan ◽  
Lin Zhu ◽  
Yi Cai Li ◽  
Jun Liu
Keyword(s):  
Random Function ◽  
Color Image ◽  
Logistic Function ◽  
Color Images ◽  
Encryption Algorithm ◽  
Key Generation ◽  
Color Image Encryption ◽  
Generation Algorithm ◽  
Key Space ◽  
Image Encryption Algorithm

Key space will be reduced after using the traditional DES algorithm to directly encrypt color images. Through combining the chaotic capability of the logistic function and by means of a specific algorithm, the fake chaotic son key’s space which is produced by the logistic chaotic pseudo-random function could be acquired. Then use the key generation algorithm to replace the traditional DES key generation algorithm. Experiment illustrates that the proposed algorithm has stronger robustness and anti-jamming capability to noise, and larger key’s space, sensitive initial keys, and better encryption effect, meanwhile it is better immune to multiple attacks.

Scattering of Poincaré waves by an irregular coastline

1973 ◽  
Vol 57 (1) ◽  
pp. 111-128 ◽  
Author(s):  
M. S. Howe ◽  
L. A. Mysak
Keyword(s):  
Energy Transfer ◽  
Random Function ◽  
Random Media ◽  
Kelvin Wave ◽  
Power Flux ◽  
Small Deviations ◽  
Transfer Processes ◽  
Dimensional Parameters ◽  
Gaussian Spectrum ◽  
Qualitative Discussion

This paper discusses the theory of the reflexion and scattering by an irregular coastline of a Poincaré-type wave on a rotating ocean. It is assumed that the coast is straight except for small deviations from the rectilinear form, and that these deviations may be regarded as a random function of position along the coast. The rigorous theory of energy-transfer processes in random media is applied to determine the power flux from the incident Poincard wave into the scattered Kelvin wave, which propagates in a unique direction along the coast, and into Poincard ocean wave noise. The relative efficiencies of generation of these waves is examined in some detail, and studied in particular for varying ranges of values of certain non-dimensional parameters characterizing the coastal configuration. Detailed estimates are given for a shoreline whose irregularities are specified by a Gaussian spectrum of Fourier components, and the results extra-polated in the concluding section of the paper to give a general qualitative discussion of the effects of an arbitrary coastline on an incident wave.

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