Security Analysis of One Verifiable Encryption Scheme

2008 ◽  
pp. 181-187
Author(s):  
Lihua Liu ◽  
Zhengjun Cao
Keyword(s):  
Security Analysis ◽  
Encryption Scheme ◽  
Verifiable Encryption

scholarly journals Improved Cryptanalysis and Enhancements of an Image Encryption Scheme Using Combined 1D Chaotic Maps

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 843 ◽  
Author(s):  
Congxu Zhu ◽  
Guojun Wang ◽  
Kehui Sun
Keyword(s):  
Image Encryption ◽  
Experimental Validation ◽  
Chaotic Maps ◽  
Color Image ◽  
Security Analysis ◽  
Transformation Process ◽  
Encryption Scheme ◽  
Color Image Encryption ◽  
Unknown Parameters ◽  
Related Approach

This paper presents an improved cryptanalysis of a chaos-based image encryption scheme, which integrated permutation, diffusion, and linear transformation process. It was found that the equivalent key streams and all the unknown parameters of the cryptosystem can be recovered by our chosen-plaintext attack algorithm. Both a theoretical analysis and an experimental validation are given in detail. Based on the analysis of the defects in the original cryptosystem, an improved color image encryption scheme was further developed. By using an image content–related approach in generating diffusion arrays and the process of interweaving diffusion and confusion, the security of the cryptosystem was enhanced. The experimental results and security analysis demonstrate the security superiority of the improved cryptosystem.

An efficient nested chaotic image encryption algorithm based on DNA sequence

2018 ◽  
Vol 29 (07) ◽  
pp. 1850058 ◽  
Author(s):  
Nabil Ben Slimane ◽  
Nahed Aouf ◽  
Kais Bouallegue ◽  
Mohsen Machhout
Keyword(s):  
Dna Sequence ◽  
Image Encryption ◽  
Chaotic Map ◽  
Security Analysis ◽  
Correlation Coefficients ◽  
Security Level ◽  
Encryption Scheme ◽  
Hash Algorithm ◽  
Encryption Schemes ◽  
Efficient Scheme

In this paper, an efficient scheme for image encryption based on the nested chaotic map and deoxyribonucleic acid (DNA) is introduced. In order to generate the initial condition values of the nested chaotic system, the Secure Hash Algorithm SHA-256 is used. The algorithm consists of two main layers: confusion and diffusion. In the first layer, the nested chaotic map is employed to create the scrambled image. The scrambled image is obtained through the ascending sorting of the first component of the nested chaotic index sequence. To ensure higher sensitivity, higher complexity and higher security, DNA sequence and DNA operator are employed additionally with the nested chaotic map and hash algorithm to modify the pixel values. The important advantages of our algorithm are the improvement of Number of Pixel Change Rate (NPCR), Unified Average Changing Intensity (UACI) and entropy, which improve resistivity against several attacks. Experimental results and relevant security analysis demonstrated that our proposed encryption scheme has the highest security level because it is more complicated, and it has a sufficiently large key space. The proposed method is compared to other recent image encryption schemes using different security analysis factors, including NPCR, UACI, correlation coefficients (CCs), encryption quality (EQ) and entropy. It is also resistant to noise (Salt and Pepper, Gaussian and speckle) and data loss attacks. The illustrated results demonstrated that the proposed image encryption scheme is efficient, and can be adopted for image encryption and transmission.

scholarly journals Security analysis of an encryption scheme based on nonpositional polynomial notations

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Nursulu Kapalova ◽  
Dilmukhanbet Dyusenbayev
Keyword(s):  
Nonlinear System ◽  
Mathematical Models ◽  
Nonlinear Equations ◽  
Security Analysis ◽  
System Of Nonlinear Equations ◽  
Encryption Scheme ◽  
File Format ◽  
Irreducible Polynomials ◽  
Number Systems ◽  
Residue Number

AbstractThe aim of the research was to conduct a cryptographic analysis of an encryption scheme developed on the basis of nonpositional polynomial notations to estimate the algorithm strength. Nonpositional polynomial notations (NPNs) are residue number systems (RNSs) based on irreducible polynomials over GF(2). To evaluate if the algorithms developed on the basis of NPNs are secure, mathematical models of cryptanalysis involving algebraic, linear and differential methods have been designed. The cryptanalysis is as follows. A system of nonlinear equations is obtained from a function transforming plaintext into ciphertext with a key. Next, a possibility of transition of the nonlinear system to a linear one is considered. The cryptanalysis was conducted for the cases with known: 1) ciphertext; 2) plaintext and the related ciphertext; 3) plaintext file format; and 4) ASCII-encoded plaintext.

Security Analysis of a Convertible Multiauthenticated Encryption Scheme

2010 ◽  
Vol 159 ◽  
pp. 111-115 ◽  
Author(s):  
Jian Hong Zhang ◽  
Xue Liu ◽  
Cheng Lian Liu
Keyword(s):  
Security Analysis ◽  
Hash Functions ◽  
Encryption Scheme ◽  
Authenticated Encryption ◽  
Transmission Scheme ◽  
Message Transmission

Multi-authenticated encryption scheme is message transmission scheme, which sends message in a secure and authentic way, and allows a group of signers to cooperatively produce a valid authenticated ciphertext so that only the specific recipient can recover the message and verify the signature. Recently, Wu et al. proposed a convertible multi-authenticated encryption scheme and claimed that the scheme was secure. In this paper, we show that Wu et. al’s scheme is not secure against rogue-key attacks. To overcome such attack, we give an improved multi-authenticated encryption scheme by including two hash functions. And our improved scheme is the same efficiency as Wu et.al.’s scheme.

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