Encryption Rounds Research Articles

A light weight secure image encryption scheme based on chaos & DNA computing

This paper proposed a new light weight secure cryptographic scheme for secure image communication. In this scheme the plain image is permuted first using a sequence of pseudo random number (PRN) and encrypted by DeoxyriboNucleic Acid (DNA) computation. Two PRN sequences are generated by a Pseudo Random Number Generator (PRNG) based on cross coupled chaotic logistic map using two sets of keys. The first PRN sequence is used for permuting the plain image whereas the second PRN sequence is used for generating random DNA sequence. The number of rounds of permutation and encryption may be variable to increase security. The scheme is proposed for gray label images but the scheme may be extended for color images and text data. Simulation results exhibit that the proposed scheme can defy any kind of attack.

Design of a tweakable image encryption algorithm using chaos-based schema

In this paper, we introduce a tweakable colour image encryption scheme based on confusion-diffusion architecture, we use the piecewise nonlinear chaotic map to generate pseudo-random sequences through the encryption process. With the addition of the tweak identical, a plain image can be encrypted to different cipher images. Thus, it is impossible for an opponent to break the scheme. Satisfactory security performances are attained by only one encryption round and the effectiveness is much enhanced. We describe our algorithm in details and illustrate its security, effectiveness and robustness by using security analysis and simulations. Comparisons with existing colour image encryption schemes have been performed showing that the proposed scheme offers very affirmative performances.

CRYPTANALYSIS OF A SYMMETRIC COLOR IMAGE ENCRYPTION WITH ONE-ROUND ENCRYPTION

We present the security weakness of encryption algorithm in the form of substitution-permutation network with multiple rounds of permutation and single round of diffusion proposed by W. Zhang et al. The types of chosen-plaintext and chosen-ciphertext attacks are successful against the cryptosystem, and the equivalent versions of keys for encryption and decryption are restored. The security analysis suggests that encryption using substitution-permutation network must be executed more than one encryption round to ensure the security. Our specific examples will demonstrate the cryptanalysis.

NARSKCA: Novel and robust symmetric key cryptography algorithm

In this research paper, a novel and strong symmetric key cryptography algorithm is proposed. NARSKCA is based on several symmetric cryptographic algorithms. NARSKCA is very simple that uses character converting algorithm, Fibonacci Number Series, Lucas Number series and bitwise XOR. In NARSKCA, 32 files are shared-secret files plays a vital role in this Proposed Algorithm. The Sub-keys are generated from those 32 shared-secret files which are useful in different rounds of Encryption and Decryption Process. The most important feature is the calculation of the final key from the Sub-Keys for each Text-Block. Key Generation, encryption/decryption schemes of NARSKCA are fast and difficult to predict by Cryptanalysts.

Differential cryptanalysis of a medical image cryptosystem with multiple rounds

Recently, Fu et al. proposed a chaos-based medical image encryption scheme that has permutation–substitution architecture. The authors believe that the scheme with bit-level cat map shuffling can be achieved at high level of security even if it is only applied with a few encryption rounds. However, we find that the scheme cannot resist differential cryptanalysis. The differential cryptanalysis shows that the security of the original scheme depends only on permutation key instead of on all of the keys. Moreover, 17 chosen plain-images can reveal equivalent permutation key for 1-round and 2-round encryption. We propose a novel analysis method called double differential cryptanalysis comparison (DDCC) that is valid to break multi-round encryption with 16N2+1 chosen plain-images, where N2 is the size of the image. We also point out several weaknesses of the cryptosystem. The theoretical analysis and simulation results indicate that the encryption scheme is insecure.

Efficient Key Management for EnforcingSecure Role Based Access Control onEncrypted Data in Cloud Storage

In the existing system, role manager give authorization to user when he begins encryption. After that user have all the permission to access the function. The project developed by access provides security by enabling the function of role manager. The role manager monitors every function to provide additional security. It includes two encryption and decryption (One by user and one by role manager. User use public & private key to encrypt and decrypt video, whereas role manager use AES to encrypt and decrypt video. Private Key frameworks utilize the same key to encode and decode information. Open key encryption functions admirably in circumstances where you can't safely impart a key, as over the Internet, however it has some real disadvantages. The main disadvantages of thistechnique are speed, certification problems, direct compromise, and false sense of security. AES encryption is a block cipher that uses an encryption key and a several rounds of encryption. A block cipher is an encryption that works on a single block of data at a time. In the case of standard AES encryption the block is 128 bits, or 16 bytes, in length. The term rounds refer to the way in which the encryption mixes the data re-encrypting it ten to fourteen times depending on the length of the key. The AES encryption itself is not a computer program or computer source code.

Improving the Diffusion of the Stream Cipher Salsa20 by Employing a Chaotic Logistic Map

The stream cipher Salsa20 and its reduced versions are among the fastest stream ciphers available today. However, Salsa20/7 is broken and Salsa20/12 is not as safe as before. Therefore, Salsa20 must completely perform all of the four rounds of encryption to achieve a good diffusion in order to resist the known attacks. In this paper, a new variant of Salsa20 that uses the chaos theory and that can achieve diffusion faster than the original Salsa20 is presented. The method has been tested and benchmarked with the original Salsa20 with a series of tests. Most of the tests show that the proposed chaotic Salsa of two rounds is faster than the original four rounds of Salsa20/4, but it offers the same diffusion level.

On optimal size in truncated differential attacks

Differential Cryptanalysis (DC) is one of the oldest known attacks on block ciphers. DC is based on tracking of changes in the differences between two messages as they pass through the consecutive rounds of encryption. However DC remains very poorly understood. In his textbook written in the late 1990s Schneier wrote that against differential cryptanalysis, GOST is “probably stronger than DES”. In fact Knudsen have soon proposed more powerful advanced differential attacks however the potential space of such attacks is truly immense. To this day there is no method which allows to evaluate the security of a cipher against such attacks in a systematic way. Instead, attacks are designed and improved in ad-hoc ways with heuristics [6–13,21]. The best differential attack known has time complexity of 2179 [13]. In this paper we show that for a given block cipher there exists an optimal size for advanced differential properties. This new understanding allows to considerably reduce the space to be searched for “good” truncated differential properties suitable for an attack.

Low-Cost Round Encryption Method for Embedded System

Advanced Encryption Standard (AES) is used in many security systems for its high security. However, the high computation complexity of the round encryption of AES makes AES hard to be performed on many embedded systems with constrained resource. This paper proposes a novel round encryption method based on a 512-Byte lookup table. The experiments results show that, the AES implementation utilizing the round encryption method proposed reaches an encryption performance comparable to that of the widely used implementation with 4 1-KB lookup tables, while consumes much less storage overhead.

Hash key-based image encryption using crossover operator and chaos

This paper proposes a color image encryption scheme using one-time keys based on crossover operator, chaos and the Secure Hash Algorithm(SHA-2). The (SHA-2) is employed to generate a 256-bit hash value from both the plain-image and the secret hash keys to make the key stream change in each encryption process. The SHA-2 value is employed to generate three initial values of the chaotic system. The permutation-diffusion process is based on the crossover operator and XOR operator, respectively. Experimental results and security analysis show that the scheme can achieve good encryption result through only one round encryption process, the key space is large enough to resist against common attacks,so the scheme is reliable to be applied in image encryption and secure communication.

A Light-weight Symmetric Encryption Algorithm Based on Feistel Cryptosystem Structure

WSNs is usually deployed in opening wireless environment, its data is easy to be intercepted by attackers. It is necessary to adopt some encryption measurements to protect data of WSNs. But the battery capacity, CPU performance and RAM capacity of WSNs sensors are all limited, the complex encryption algorithm is not fitted for them. The paper proposed a light-level symmetrical encryption algorithm: LWSEA, which adopt minor encryption rounds, shorter data packet and simplified scrambling function. So the calculation cost of LWSEA is very low. We also adopt longer-bit Key and circular interpolation method to produce Child-Key, which raised the security of LWSEA. The experiments demonstrate that the LWSEA possess better ―avalanche effect‖ and data confusion degree, furthermore, its calculation speed is far faster than DES, but its resource cost is very low. Those excellent performances make LWSEA is much suited for resource-restrained WSNs.

Key-Dependent Nonlinear Component for Block Cipher Encryption Algorithm

In this paper, we propose a 128-bit Feistel square cryptosystem, which all the while captivates key-subordinate S-box and key-subordinate P-box. With these two key-subordinate changes, the inside structure of this cryptosystem calculation is secured, in order to oppose the direct and differential cryptanalysis in a couple round encryptions. Thus, the encryption what's more decoding capacities are very proficient. We named this key-ward structure the DSDP structure, and the cryptosystem DSDP. A quick change calculation is utilized to create both the key-subordinate S-box and key-subordinate P-boxes. This enormously repays the execution penalty of complex key plan. The essential operations utilized as a part of DSDP are all proficient byte wise operations, so the calculation will have a sensible quick speed on late processors, 16-bit processors and shrewd cards and in addition 8-bit processors. We execute the calculation with C what's more Java separately on a few PCs with diverse processors, what's more gauge the upgraded get together execution on Pentium. The exploratory results and the estimation demonstrates that DSDP has a quick encryption/unscrambling rate and a sensible quick key planning execution.

A fast image encryption scheme with a novel pixel swapping-based confusion approach

In traditional permutation-diffusion type image cipher, the confusion and diffusion are two independent procedures. In general, several overall rounds are required to achieve a satisfactory security level, which downgrades its advantage in online image protection. In this paper, a novel plain pixel-related swapping confusion approach that can contribute considerable diffusion effect in the permutation procedure is proposed. By employing the self-related non-linear pixel swapping confusion approach, a tiny difference between two plain images can bring about completely different confused images. Therefore, the spreading process of the cryptosystem is significantly accelerated, and the workload of the time-consuming diffusion part will be reduced. Moreover, an improved image encryption architecture is proposed in conjunction with the pixel swapping-based confusion approach. Compared with the typical permutation-diffusion structure, the new architecture well addresses the weakness of confusion key sensitivity in the first encryption round. Simulation results and numerical analyses justify the higher efficiency and sufficient strength of the proposed image encryption scheme.

An improved permutation-diffusion type image cipher with a chaotic orbit perturbing mechanism

During the past decades, chaos-based permutation-diffusion type image cipher has been widely investigated to meet the increasing demand for real-time secure image transmission over public networks. However, the existing researches almost exclusively focus on the improvements of the permutation and diffusion methods independently, without consideration of cooperation between the two processes. In this paper, an improved permutation-diffusion type image cipher with a chaotic orbit perturbing mechanism is proposed. In the permutation stage, pixels in the plain image are shuffled with a pixel-swapping mechanism, and the pseudorandom locations are generated by chaotic logistic map iteration. Furthermore, a plain pixel related chaotic orbit perturbing mechanism is introduced. As a result, a tiny change in plain image will be spread out during the confusion process, and hence an effective diffusion effect is introduced. By using a reverse direction diffusion method, the introduced diffusion effect will be further diffused to the whole cipher image within one overall encryption round. Simulation results and extensive cryptanalysis justify that the proposed scheme has a satisfactory security with a low computational complexity, which renders it a good candidate for real-time secure image storage and distribution applications.

Color image encryption using one-time keys and coupled chaotic systems

This paper proposes a color image encryption scheme using one-time keys based on coupled chaotic systems. The key stream has both the key sensitivity and the plaintext sensitivity. The Secure Hash Algorithm 3 (SHA-3) is employed to combine with the initial keys to generate the new keys, to make the key stream change in each encryption process. Firstly, the SHA-3 hash value of the plain image is employed to generate six initial values of the chaotic systems. Secondly, combine and permute the six state variables, and randomly select three state variables from them, to encrypt the red, green and blue components, respectively. Experimental results and security analysis show that the scheme can achieve good encryption result through only one round encryption process, the key space is large enough to resist against common attacks, so the scheme is reliable to be applied in image encryption and secure communication.

Security assessment on block-Cat-map based permutation applied to image encryption scheme

Recently, an image encryption scheme is proposed using block-Cat-map based permutation and chaos based substitution. This paper investigates the security of the scheme. As for different images, the keys keep fixed, so the chaotic keystreams generated by they are also unchanged. Our target is to reveal these chaotic keystreams equivalent to the chaotic keys by using chosen plaintext attack. Security assessment shows that all the keystreams can be revealed by choosing eight images for the situation of only one round encryption. In addition, only the block-Cat-map based permutation can be cryptanalyzed by choosing seven special images.

A block image encryption algorithm based on wave transmission and chaotic systems

A block-based image encryption algorithm using wave function and chaotic system is presented. A random sequence generated by the chaotic system is used to find the source point in the wave and produces a diffusion matrix for modular operation. In the encryption process, the keystream is dependent on both the plain-image and the secret key. It changes in each encryption round. Theoretical analyses and simulation results show the high security of the proposed method, including the large key space, fairly uniform histogram, zero correlation between neighbouring pixels, resistance to differential attacks, and high efficiency. Therefore, our algorithm is a practical scheme for digital image encryption.

A fast chaotic block cipher for image encryption

Image encryption schemes based on chaos usually involve real number arithmetic operations to generate the chaotic orbits from the chaotic system. These operations are time-consuming and are normally performed with high-end processors. To overcome this drawback, this paper proposes a one round encryption scheme for the fast generation of large permutation and diffusion keys based on the sorting of the solutions of the Linear Diophantine Equation (LDE) whose coefficients are integers and dynamically generated from any type of chaotic systems. The high security and low computational complexity are achieved not only by using large permutation based on the sorting of the solutions of LDE but also by generating only one permutation from the sorting of the solutions of the LDE, then by dynamically updating d number of integers (d>2) in the permutation. The performance of the proposed scheme is evaluated using various types of analysis such as entropy analysis, difference analysis, statistical analysis, key sensitivity analysis, key space analysis and speed analysis. The experimental results indicate that the proposed algorithm is secure and fast as compared to the two round encryption scheme.

A Cipher Design with Automatic Key Generation using the Combination of Substitution and Transposition Techniques and Basic Arithmetic and Logic Operations

Modern computing is observed to be highly dependent on communication and data transport. The security of data during communication has become a mandatory need since the introduction of e-commerce, mails, etc. Moreover a lot of data may be required to be kept secure on local devices also. The encryption of data is the basic requirement today and thus helps to maintain confidentiality of data. A number of algorithms are available for encrypting data while it is transferred from sender to receiver. In this paper we have proposed a cipher which uses basic encryption techniques of substitution and transposition along with application of logic gates, in order to encrypt the data. The algorithm makes cryptanalysis even more difficult because of the use of Random Number Generator function which further decides order of encryption rounds and keys to be used to encrypt the plain text. This eliminates the overhead of defining a fixed key by the user and makes algorithm secure also. It also facilitates to transfer the key to the receiver while being added with the plain text at random locations (like added at end or beginning).

Hybridize Dynamic Symmetric Key Cryptography using LCG

In the present work, a block cipher is presented which deals with a dynamic symmetric key cryptographic method using substitution and transposition technique. In this work a dynamic secret key is generated using Linear Congruential Generator (LCG). The striking feature of the present work is creation of a new secret key for every pair of encryption and decryption operation, thus secret key is a dynamic key. After encryption and decryption operation the dynamic key is discarded. The proposed cryptography method is a process consisting of two rounds of encryption and two rounds of decryption. The key generation algorithm uses SHA-1 hashing scheme to produce key of size 196 bits. This key is used to encrypt plain text of variable size. Since this is a block cipher method authors divide the variable size plaintext into ‘n’ fixed size (49 bit) blocks. The notion of dynamic key has evolved from the concept of the one time pad. Different parts of dynamic secret key are used in different places in order to make it harder for cryptanalysis or attacks.