Showing papers on "Transposition cipher published in 2016"

Strumok stream cipher: Specification and basic properties

Abstract: STRUMOK is a word-oriented additive stream cipher, where a word in the specification is chosen to be 64 bits. STRUMOK cipher uses some basic design principles from the stream cipher SNOW 2.0. STRUMOK aims at improving SNOW 2.0 both from the security and from the efficiency points of view. Most notably, it uses a more productive keystream generation procedure.

Cryptanalyzing an image encryption algorithm based on scrambling and Veginère cipher

Abstract: Recently, an image encryption algorithm based on scrambling and Veginere cipher has been proposed. However, it was soon cryptanalyzed by Zhang et al. using a method composed of both chosen-plaintext attack and differential attacks. This paper briefly reviews the two attack approaches proposed by Zhang et al. and outlines their mathematical interpretations. Based on these approaches, we present an improved chosen-plaintext attack to further reduce the number of chosen-plaintexts required, which is proved to be optimal. Moreover, it is found that an elaborately designed known-plaintext attack can efficiently compromise the image cipher under study. This finding is confirmed by both mathematical analysis and numerical simulations. The cryptanalyzing techniques developed in this paper provide some insights for designing secure and efficient multimedia ciphers.

Cryptanalysis of a High-Definition Image Encryption Based on AES Modification

Abstract: Wadi and Zainal recently proposed a high definition image encryption algorithm based on a modified AES-128 block cipher in (Wirel Pers Commun 79(2):811---829, 2014). In this paper, we show that the core component of their image encryption algorithm, a modified AES-128 cipher, is insecure against impossible differential attack. The proposed impossible differential attack on the full rounds of the modified AES-128 cipher has a time complexity of around $$2^{88.74}$$288.74 encryptions with $$2^{114.06}$$2114.06 chosen plaintexts and $$2^{99}$$299 bytes of memory, in contrast to the expected security of $$2^{128}$$2128. The existence of such an attack disproves the claims made by the designers that their modified AES-128 cipher improves the security of the AES cipher and that it can subsequently be used to construct a secure image encryption scheme. The root cause of this attack, some other issues with the modified AES cipher and possible solutions are described to serve as important remarks in designing a secure image encryption scheme.

Strengthening the Known-Key Security Notion for Block Ciphers

Abstract: We reconsider the formalization of known-key attacks against ideal primitive-based block ciphers. This was previously tackled by Andreeva, Bogdanov, and Mennink FSEi¾?2013, who introduced the notion of known-key indifferentiability. Our starting point is the observation, previously made by Cogliati and Seurin EUROCRYPTi¾?2015, that this notion, which considers only a single known key available to the attacker, is too weak in some settings to fully capture what one might expect from a block cipher informally deemed resistant to known-key attacks. Hence, we introduce a stronger variant of known-key indifferentiability, where the adversary is given multiple known keys to "play" with, the informal goal being that the block cipher construction must behave as an independent random permutation for each of these known keys. Our main result is that the 9-round iterated Even-Mansour construction with the trivial key-schedule, i.e., the same round key xored between permutations achieves our new "multiple" known-keys indifferentiability notion, which contrasts with the previous result of Andreeva et al. that one single round is sufficient when only a single known key is considered. We also show that the 3-round iterated Even-Mansour construction achieves the weaker notion of multiple known-keys sequential indifferentiability, which implies in particular that it is correlation intractable with respect to relations involving any polynomial number of known keys.

A triple hill cipher algorithm proposed to increase the security of encrypted binary data and its implementation using FPGA

Abstract: Encrypted binary data security is an important task in the field of data communication systems since many decades. In this paper, we study the security problem and present a proposed triple hill cipher algorithm and its implementation on FPGA to encrypt any binary data such as images, audio, video … etc. The proposed algorithm uses three stages of a modified hill cipher to make the algorithm more robust and gives high level security of the data, each stage is considered a block cipher with a block length of 128 bits and key length of 256 bits. The message to be encrypted is processed by this block cipher in three stages. The keys are taken from random number generator. The proposed algorithm is promising to give better security.

An AES-Like Cipher and Its White-Box Implementation

Abstract: White-box cryptography aims at implementing a cipher to protect its key from being extracted in an untrusted environment, where the attacker has full access to the execution of the cryptographic software. In 2002, Chow proposed the original white-box implementation of AES. Afterwards, various white-box implementations were presented. However, they were all badly broken because of a weakness of the implemented cryptographic algorithms: every parameter of the cryptographic operations is fixed except the round keys. In this paper, we present an AES-like cipher based on key-dependent S-boxes. The new cipher is designed to meet the design criteria of AES and hence provides a security level comparable to AES to resist black-box attacks. Moreover, we present a white-box implementation for our AES-like cipher, which is sufficient to withstand existing white-box attacks.

Cryptanalysis of columnar transposition cipher with long keys

Abstract: The classical columnar transposition cipher was the most popular type of transposition cipher. It was in use mainly during the second half of the nineteenth century and the first half of the twentieth century. It also served as a building block for more complex ciphers, such as the ADFGVX cipher and the double transposition cipher. Pen-and-paper as well as computerized methods for the cryptanalysis of the columnar transposition cipher have been published, but those apply mainly to the easier cases of short keys and complete transposition rectangles. In this article, a novel approach for the cryptanalysis of the columnar transposition cipher when used with long keys is presented. It is based on a two-phase hill climbing algorithm, a two-dimensional fitness score, and special transformations on key segments. This ciphertext-only method allows for the recovery of transposition keys with up to 1,000 elements, and up to 120 elements for worst case transposition rectangles.

Implementation of Affine Transform Method and Advanced Hill Cipher for securing digital images

Abstract: Digital image security aims to protect the image of the confidential access by parties that do not have the authority. Security on the research done by encrypting and decrypting digital image in PNG, BMP and JPEG using two methods are Affine Transform and Advanced Hill Cipher. Affine Transform method for scrambling pixel positions and methods Advanced Hill Cipher to change the pixel values. The safety analysis of the methods Affine Transform and Advanced Hill Cipher using entropy and the correlation coefficient. This study proves that the combined method Affine Transform and Advanced Hill Cipher can be merged to digital image information security.

Security analysis and enhanced design of a dynamic block cipher

Abstract: There are a lot of security issues in block cipher algorithm. Security analysis and enhanced design of a dynamic block cipher was proposed. Firstly, the safety of ciphertext was enhanced based on confusion substitution of S-box, thus disordering the internal structure of data blocks by four steps of matrix transformation. Then, the diffusivity of cipher-text was obtained by cyclic displacement of bytes using column ambiguity function. The dynamic key was finally generated by using LFSR, which improved the stochastic characters of secret key in each of round of iteration. The safety performance of proposed algorithm was analyzed by simulation test. The results showed the proposed algorithm has a little effect on the speed of encryption and decryption while enhancing the security. Meanwhile, the proposed algorithm has highly scalability, the dimension of S-box and the number of register can be dynamically extended according to the security requirement.

A new chaos-based image cipher using a hash function

Abstract: This paper presents a new chaos-based image cipher using a plaintext-related permutation. The cat map and Lorenz system are employed to shuffle the positions of image pixels and generate the diffusion keystream, respectively. The control parameters of the cat map, i.e. the permutation key, are determined by the Murmur2 hash value of the original image. Owing to the avalanche property of hash functions, completely different shuffled images will be produced even if there is a tiny difference between the original ones, and it helps accelerate the diffusion process. Experimental results indicate that the proposed scheme requires only one and two cipher cycles to achieve an acceptable and a satisfactory diffusion properties, respectively, whereas two and three cipher cycles are needed by typical schemes to achieve the same properties. Thorough security analysis is carried out, and the results demonstrate the satisfactory security of the proposed scheme.

Mapping private keys into one public key using binary matrices and masonic cipher: Caesar cipher as a case study

Abstract: Caesar cipher is a mono alphabetic cipher. It is also a type of substitution cipher in which each letter in the plaintext is “shifted” a certain number of places down the alphabet. However, Caesar cipher method did not last long because of its simplicity and lack of communication security. Therefore, we believe that strengthen the key mechanism should increase its complexity against the various cryptanalysis attacks. This paper proposes an enhanced Caesar cipher method through adopting two private keys that are tied to the character positions (i.e. odd and even) for encryption and/or decryption. The two private keys are mapped into one public key to be transferred to the recipient. At the end, the results show that the new cryptosystem is inevitable to cryptanalysis attack. And the cipher text is reduced in size and thus, memory space. The public key generation process is proven to be a one-way function utilizing binary matrices that are generated and shared between the two communicating parties. Copyright © 2016 John Wiley & Sons, Ltd.

Quantum enigma cipher as a generalization of the quantum stream cipher

Abstract: Various types of randomizations for the quantum stream cipher by Y00 protocol have been developed so far. In particular, it must be noted that the analysis of immunity against correlation attacks with a new type of randomization by Hirota and Kurosawa prompted a new look at the quantum stream cipher by Y00 protocol (Quant. Inform. Process. 6(2) 2007). From the preceding study on the quantum stream cipher, we recognized that the quantum stream cipher by Y00 protocol would be able to be generalized to a new type of physical cipher that has potential to exceed the Shannon limit by installing additional randomization mechanisms, in accordance with the law of quantum mechanics. We call this new type of physical random cipher the quantum enigma cipher. In this article, we introduce the recent developments for the quantum stream cipher by Y00 protocol and future plans toward the quantum enigma cipher.

An Automatic Cryptanalysis of Transposition Ciphers Using Compression

Abstract: Automatically recognising valid decryptions as a result of ciphertext only cryptanalysis of simple ciphers is not an easy issue and still considered as a taxing problem In this paper, we present a new universal compression-based approach to the automatic cryptanalysis of transposition ciphers In particular, we show how a Prediction by Partial Matching (PPM) compression model, a scheme that performs well at many language modelling tasks, can be used to automatically recognise the valid decrypt with a 100 % success rate We also show how it significantly outperforms another compression scheme, Gzip In this paper, we propose a full mechanism for the automatic cryptanalysis of transposition ciphers which also automatically adds spaces to decrypted texts, again using a compression-based approach, in order to achieve readability

On the primitivity of PRESENT and other lightweight ciphers.

Abstract: We provide two sufficient conditions to guarantee that the round functions of a translation based cipher generate a primitive group. Furthermore, under the same hypotheses, and assuming that a round of the cipher is strongly proper and consists of m-bit S-Boxes, with m = 3; 4 or 5, we prove that such a group is the alternating group. As an immediate consequence, we deduce that the round functions of some lightweight translation based ciphers, such as the PRESENT cipher, generate the alternating group.

Cryptographic Properties of a New National Encryption Standard of Ukraine

Abstract: The block cipher "Kalyna" was recently accepted as a new national encryption standard of Ukraine. In this article, the most important properties of components of this cipher are analyzed. It is shown that round transformations of "Kalyna" generate an alternating permutation group and that the cipher itself is provably secure against differential and linear cryptanalysis.

Cryptanalytic Attacks on International Data Encryption Algorithm Block Cipher

Abstract: International data encryption algorithm (IDEA) is a secret key or symmetric key block cipher. The purpose of IDEA was to replace data encryption standard (DES) cipher, which became practically insecure due to its small key size of 56 bits and increase in computational power of systems. IDEA cipher mainly to provides data confidentiality in variety of applications such as commercial and financial application e.g. pretty good privacy (PGP) protocol. Till 2015, no successful linear or algebraic weaknesses of IDEA of have been reported. In this paper, author explained IDEA cipher, its application in PGP and did a systematic survey of various attacks attempted on IDEA cipher. The best cryptanalysis result which applied to all keys could break IDEA up to 6 rounds out of 8.5 rounds of the full IDEA cipher 1 . But the attack requires 2 64 known plaintexts and 2 126.8 operations for reduced round version. This attack is practically not feasible due to above mentioned mammoth data and time requirements. So IDEA cipher is still completely secure for practical usage. PGP v2.0 uses IDEA cipher in place of BassOmatic which was found to be insecure for providing data confidentiality.

Square and boomerang attacks analysis of diffusion property of 3D-AES block cipher

Abstract: The antigen-antibody interaction, somatic hyper mutation and protein structural features in immune systems have been selected as inspired approach in designing the new block cipher algorithm called 3D-AES. However, these computation elements from immune systems have not proved yet whether it can be successfully applied and satisfies with Shannon's diffusion property in designing a new block cipher algorithm. This paper introduces two different types of attacks on the proposed block cipher. This paper measures and analyses the diffusion property of the block cipher by square attack and boomerang attack. It also discussed the best possible diffusion and described how it is relevant for chosen plaintext attack and conventional non related-key attacks based on the experiment done in the contact of the wide trail strategy family.

Multiple text encryption, key entrenched, distributed cipher using pairing functions and transposition ciphers

Abstract: The process of distributing information in a secured way is called Secured Communication. Secured information involves Encryption procedure at the sender side and Decryption process at the receiver side of the communication system. Many Ciphers have been developed to provide data guard. The effectiveness of the Ciphers that are being used depends mainly on their throughput and memory constraint. The proposed method encrypts two messages at a time with the help pairing function so that it reduces the size to half of original length. The key is embedded within the cipher text with the help of transposition ciphers. The proposed method decrypts the single message (which is transmitted) into two messages with the help of depairing functions.

Robust chaos-based stream-cipher for secure public communication channels

Abstract: In this paper, we propose a novel stream cipher based on a chaotic system. In order to get the cipher text, the plain text is simply XORed with the key-stream generated by a strong pseudo chaotic number generator (PCNG). Then, all the security of the system is based on the used PCNG. The structure of the proposed PCNG includes two chaotic maps which are weakly coupled by a predefined matrix and integrates a swap function. The PCNG passes all statistical NIST's randomness tests. Also, analysis and experimental results show that the proposed stream cipher has a large key space, a high key sensitivity, and can resist against chosen-plaintext attack and chosen-ciphertext attack. Indeed, for each new execution of the system using the same secret key, the generated key-stream is different due to the IV-setup function. The computing performance of the proposed system is comparable to the main algorithms of eStream such as Rabbit and HC-128.

Symmetric Cryptography using Multiple Access Circular Queues (MACQ)

Abstract: In order to provide secure data communication in present cyber space world, a stronger encryption technique becomes a necessity that can help people to protect their sensitive information from cryptanalyst. This paper proposes a novel symmetric block cipher algorithm that uses multiple access circular queues (MACQs) of variable lengths for diffusion of information to a greater extent. The keys are randomly generated and will be of variable lengths depending upon the size of each MACQ.A number of iterations of circular rotations, swapping of elements and XORing the key with queue elements are performed on each MACQ. S-box is used so that the relationship between the key and the cipher text remains indeterminate or obscure. These operations together will help in transforming the cipher into a much more complex and secure block cipher. This paper attempt to propose an encryption algorithm that is secure and fast.

Cryptanalysis of AES-128 and AES-256 Block Ciphers Using Lorenz Information Measure

Abstract: Encryption algorithms will transform a human interpretable text block or information in to a non-interpretable block of symbols. The objective of any such encryption algorithm will be making the cipher block more non-interpretable and seemingly random block of symbols. So any cipher block will always be random and will purely be a set of random permutations of symbols. The efforts of distinguishing the cipher text of a cipher from random permutation and distinguishing a cipher blocks of different algorithms are called as "distinguisher attacks". Generally, almost all the classical ciphers are distinguishable and even breakable. But the modern ciphers have been designed to withstand against several kinds of attacks and even withstand against distinguisher attack. It means, we cannot even guess the type of cipher used for encryption only by seeing/analyzing the encrypted block of symbols. In this work our focus will be only on distinguisher attack on modern ciphers. For that, we have attempted to distinguish the cipher blocks of AES-128 and AES-256 using a metric called Lorenz Information Measure (LIM) which is commonly used in image and signal classification systems. In our findings, we showed that the cipher blocks of AES-128 and AES-256 are certainly distinguishable from one another.

Cryptanalytic Attacks on IDEA Block Cipher

Abstract: International data encryption algorithm (IDEA) is a secret key or symmetric key block cipher The purpose of IDEA was to replace data encryption standard (DES) cipher, which became practically insecure due to its small key size of 56 bits and increase in computational power of systems IDEA cipher mainly to provide data confidentiality in variety of applications such as commercial and financial application eg pretty good privacy (PGP) protocol Till 2015, no successful linear or algebraic weaknesses IDEA of have been reported In this paper, author explained IDEA cipher, its application in PGP and did a systematic survey of various attacks attempted on IDEA cipher The best cryptanalysis result which applied to all keys could break IDEA up to 6 rounds out of 85 rounds of the full IDEA cipher1 But the attack requires 264 known plaintexts and 21268 operations for reduced round version This attack is practically not feasible due to above mention mammoth data and time requirements So IDEA cipher is still completely secure for practical usage PGP v20 uses IDEA cipher in place of BassOmatic which was found to be insecure for providing data confidentiality

Automated Proofs of Block Cipher Modes of Operation

Abstract: We present a Hoare logic for proving semantic security and determining exact security bounds of a block cipher mode of operation. We propose a simple yet expressive programming language to specify encryption modes, semantic functions for each command (statement) in the language, an assertion language that allows to state predicates and axioms, and rules to propagate the predicates through the commands of a program. We also provide heuristics for finding loop invariants that are necessary for the application of our rule on for-loops. This enables us to prove the security of protocols that take arbitrary length messages as input. We implemented a prototype that uses this logic to automatically prove the security of block cipher modes of operation. This prototype can prove the security of many standard modes of operation, such as Cipher Block Chaining (CBC), Cipher FeedBack mode (CFB), Output FeedBack (OFB), and CounTeR mode (CTR).

Encryption of images using XOR Cipher

Abstract: These days, the major form of data used by a common person is images. And there have been multiple leaks of private images in the closer past due to application flaws. This paper proposes using XOR Cipher to encrypt the binary data in images pixel by pixel rather than securing it with an application so that it cannot be exploited or cracked easily. The proposed model explains multiple ways to encrypt the Image using XOR Cipher and the analysis shows that by using the proposed model, the images are properly encrypted. The proposed model was tested on various images including Mona Lisa, Apollo 11 and NebulaM83 and proper results were yielded.

PFC-CTR, PFC-OCB: Efficient stream cipher modes of authencryption

Abstract: Authencryption is a cryptographic process of providing confidentiality and integrity protection of messages in a single pass, simultaneously, without any support of conventional checksum, MAC, or hash function. This article encompasses the process to construct the stream cipher-based authencryption environment, where the keystream is generated from any secure block algorithm like AES. Accordingly, in order to demonstrate the working principle of authencryption in the stream cipher environment, the authors introduce two stream cipher modes of authencryption, namely, PFC-CTR and PFC-OCB. PFC-CTR denotes the counter-based authencryption environment, and PFC-OCB specifies the authencryption environment built upon the underlying foundation of OCB. They argue that both of the proposed stream cipher modes of authencryption are quite robust against several active attacks e.g., message stream modification attacks, known-plain-text attacks, and chosen-plain-text attacks. At the same time, they can efficiently deal with other issues like “limited error propagation,” and so on, existing in several conventional stream cipher modes of operation like CFB, OFB, and CTR.

Meet-in-the-Middle Attack on QARMA Block Cipher.

Abstract: QARMA is a recently published lightweight tweakable block cipher, which has been used by the ARMv8 architecture to support a software protection feature. In this paper, using the method of MITM, we give the first distinguisher of QARMA block cipher. It is made up of the Pseudo-Reflector construction with two forward rounds and three backward rounds. By adding two rounds on the top and three rounds on the bottom of the distinguisher, together with the idea of the differential enumeration technique and the key-dependent sieve skill, we achieve a 10-round (of 16-round) key recovery attack with memory complexity of 2 192-bit space, data complexity of 2 chosen plaintexts and time complexity of 2 encryption units. Furthermore, we use the same distinguisher to attack QARMA-128 which also includes 10 (of 24) round functions and the Pseudo-Refector construction. The memory complexity is 2 384-bit space, the data complexity is 2 chosen plaintexts and the time complexity is 2 encryption units. These are the first attacks on QARMA and do not threaten the security of full round QARMA.