Substitution-permutation Network Research Articles

Classification of SPN Structures From the Viewpoint of Structural Cryptanalysis

In this paper, we provide two types of pattern matrices for the diffusion layer P, both can be used as classification criteria for the substitution-permutation network (SPN) structures: if the pattern matrices of distinct SPN structures are equal, then these structures may have the same impossible differential (ID)/zero correlation linear hull (ZC) and the same differential/linear active S-boxes. We introduce some interesting properties of the pattern matrices. Applying our results, we arrive at several interesting facts. First, all the SPN structures with MDS-type diffusion layers fall into the same class and have the same ID/ZC/minimum number of active S-boxes. Second, we provide several interesting properties of pattern matrices and build the links between the P-layer and that after several popular operations. Finally, we investigate the properties of pattern matrices for bit shuffles, the pattern matrices keep the same if and only if the n-partition characteristics of them are equal. Our results are helpful in the designing of block ciphers.

An Effective Lightweight Cryptographic Algorithm to Secure Resource-Constrained Devices

In recent years, small computing devices like embedded devices, wireless sensors, RFID tags (Radio Frequency Identification), Internet of Things (IoT) devices are increasing rapidly. They are expected to generate massive amount of sensitive data for controlling and monitoring purposes. But their resources and capabilities are limited. Those also work with valuable private data thus making security of those devices of paramount importance. Therefore, a secure encryption algorithm should be there to protect those vulnerable devices. Conventional encryption ciphers like RSA or AES are computationally expensive; require large memory but hinder performances of those devices. Simple encryption techniques, on the other hand are easy to crack, compromising security. In this paper a secure and efficient lightweight cryptographic algorithm for small computing devices has been proposed. It is a symmetric key block cipher, employing custom substitution-permutation (SP) network and a modified Feistel architecture. Two basic concepts from Genetic algorithm are used. A Linux based benchmark tool, FELICS is used for the measurement and MATLAB for the purpose of encryption quality testing. An improvement over the existing algorithm, the proposed algorithm reduces the use of processing cycles but at the same time provides sufficient security.

Security Analysis of Some Diffusion Mechanisms Used in Chaotic Ciphers

As a variant of the substitution–permutation network, the permutation–diffusion structure has received extensive attention in the field of chaotic cryptography over the last three decades. Because of the high implementation speed and nonlinearity over GF([Formula: see text]), the Galois field of two elements, mixing modulo addition/multiplication and Exclusive OR becomes very popular in various designs to achieve the desired diffusion effect. This paper reports that some diffusion mechanisms based on modulo addition/multiplication and Exclusive OR are not resistant to plaintext attacks as claimed. By cracking several recently proposed chaotic ciphers as examples, it is demonstrated that a good understanding of the strength and weakness of these crypto-primitives is crucial for designing more practical chaotic encryption algorithms in the future.

Timing Attack and Countermeasure on NEMS Relay Based Design of Block Ciphers

Scaling down CMOS technology results in excessive power dissipation issues. Nanoelectromechanical System (NEMS) relay technology is an alternative emerging solution that overcomes the power dissipation limitation of CMOS technology. However, despite its zero static leakage, NEMS relay technology suffers from large delay compared to CMOS technology. Binary Decision Diagram (BDD) based implementations of NEMS relay design targets minimizing the total delay. However, this implementation renders the timing delay of the output of a BDD input-dependent, which is a threat to security-critical applications, such as ciphers. In this paper, we analyze the impact of the input-dependent timing variation on the security of NEMS relay based cipher implementations. We present a generalized timing attack methodology, which is applicable to both Substitution Permutation Network (SPN) as well as Feistel block ciphers. We provide case studies on state-of-the-art SPN cipher candidate Advanced Encryption Standard (AES) and Feistel cipher candidates Camellia and DES. Our attack analysis shows that compact designs with single S-box implementation can be compromised, while parallel S-box implementations possess an inherent resistance against timing attacks. We also propose a cost-effective countermeasure which eliminates the input-dependent timing variation and thwarts all such timing attacks on BDD based implementations of NEMS relay design.

Pengembangan Algoritma Advanced Encryption Standard pada Sistem Keamanan SMS Berbasis Android Menggunakan Algoritma Vigenere

Short Message Service (SMS) is working on a wireless network that allows the theft of the message contents. There are risks that could threaten the security of the contents of the message on SMS services, including SMS snooping, and SMS interception. Therefore, it takes security system messages on SMS services to maintain the security and integrity of the message content to cover the security messages. Algorithms Advanced Encryption Standard (AES) using a structure SPN (Substitution Permutation Network) structure, which has the disadvantage of encryption and decryption, so the safety level is low. To cover the security hole of these weaknesses, the researchers conducted the improvement of Advanced Encryption Standard (AES) algorithm security system based on android SMS using Vigenere algorithm, so that the level of security and integrity of the content of the short message becomes higher and difficult to solve. The results showed an average increase in percentage value of the avalanche effect from 37.24% to 42.96%.
 Keywords—Advanced Encryption Standard, android, message security, encryption.

Searching all truncated impossible differentials in SPN

This study concentrates on finding all truncated impossible differentials in substitution-permutation networks (SPNs) ciphers. Instead of using the miss-in-the-middle approach, the authors propose a mathematical description of the truncated impossible differentials. First, they prove that all truncated impossible differentials in an r + 1 rounds SPN cipher could be obtained by searching entry `0' in D ( P ) r , where D ( P ) denotes the differential pattern matrix (DPM) of P -layer, thus the length of impossible differentials of an SPN cipher is upper bounded by the minimum integer r such that there is no entry `0' in D ( P ) r . Second, they provide two efficient algorithms to compute the DPMs for both bit-shuffles and matrices over GF(2 n ). Using these tools they prove that the longest truncated impossible differentials in SPN structure is 2-round, if the P -layer is designed as an maximum distance separable (MDS) matrix. Finally, all truncated impossible differentials of advanced encryption standard (AES), ARIA, AES-MDS, PRESENT, MAYA and Puffin are obtained.

Design of image cipher using block-based scrambling and image filtering

The operation of image filtering is widely used to deblur digital images. However, using inappropriate masks, it can also blur images. Motivated by this concept, this paper introduces an image cipher using block-based scrambling and image filtering (IC-BSIF). To the best of our knowledge, this is the first time that image filtering has been used for image encryption. IC-BSIF uses the well-known substitution-permutation network and strictly follows the concepts of confusion and diffusion. The block-based scrambling is able to separate neighboring pixels to different rows and columns, and thus can efficiently weaken the strong correlations between adjacent pixels. Using randomly generated masks by the secret key, the image filtering can spread little change of plain-images to the entire pixels of cipher-images. Simulation results show that IC-BSIF can encrypt different kinds of images into noise-like ones, and security evaluations demonstrate that it can achieve better performance than several state-of-the-art encryption schemes.

Light-weight white-box encryption scheme with random padding for wearable consumer electronic devices

Wearable devices can be potentially captured or accessed in an unauthorized manner because of their physical nature. In such cases, they are in white-box attack contexts, where the adversary may have total visibility on the implementation of the built-in cryptosystem, with full control over its execution platform. Dealing with white-box attacks on wearable devices is undoubtedly a challenge. To serve as a countermeasure against threats in such contexts, we propose a lightweight encryption scheme to protect the confidentiality of data against white-box attacks. We constructed the scheme’s encryption and decryption algorithms on a substitution-permutation network that consisted of random secret components. Moreover, the encryption algorithm uses random padding that does not need to be correctly decrypted as part of the input. This feature enables non-bijective linear transformations to be used in each encryption round to achieve strong security. The required storage for static data is relatively small and the algorithms perform well on various devices, which indicates that the proposed scheme satisfies the requirements of wearable computing in terms of limited memory and low computational power.

SIT: A Lightweight Encryption Algorithm for Secure Internet of Things

The Internet of Things (IoT) being a promising technology of the future is expected to connect billions of devices. The increased number of communication is expected to generate mountains of data and the security of data can be a threat. The devices in the architecture are essentially smaller in size and low powered. Conventional encryption algorithms are generally computationally expensive due to their complexity and requires many rounds to encrypt, essentially wasting the constrained energy of the gadgets. Less complex algorithm, however, may compromise the desired integrity. In this paper we propose a lightweight encryption algorithm named as Secure IoT (SIT). It is a 64-bit block cipher and requires 64-bit key to encrypt the data. The architecture of the algorithm is a mixture of feistel and a uniform substitution-permutation network. Simulations result shows the algorithm provides substantial security in just five encryption rounds. The hardware implementation of the algorithm is done on a low cost 8-bit micro-controller and the results of code size, memory utilization and encryption/decryption execution cycles are compared with benchmark encryption algorithms. The MATLAB code for relevant simulations is available online at https://goo.gl/Uw7E0W.

BER-Based Physical Layer Security With Finite Codelength: Combining Strong Converse and Error Amplification

A bit error rate (BER)-based physical layer security approach is proposed for finite blocklength. For secure communication in the sense of high BER, the information-theoretic strong converse is combined with cryptographic error amplification achieved by substitution permutation networks (SPNs) based on confusion and diffusion. For discrete memoryless channels (DMCs), an analytical framework is provided showing the tradeoffs among finite blocklength, maximum/minimum possible transmission rates, and BER requirements for the legitimate receiver and the eavesdropper. Also, the security gap is analytically studied for Gaussian channels and the concept is extended to other DMCs including binary symmetric channels (BSCs) and binary erasure channels (BECs). For fading channels, the transmit power is optimized to minimize the outage probability of the legitimate receiver subject to a BER threshold for the eavesdropper.

A novel image encryption scheme based on substitution-permutation network and chaos

In this paper, a novel image encryption approach based on permutation-substitution (SP) network and chaotic systems is proposed. It consists of four cryptographic phases: diffusion, substitution, diffusion and permutation. Firstly, a diffusion phase is proposed based on new chaotic map. Then, a substitution phase based on strong S-boxes followed by a diffusion phase based on chaotic logistic map are presented which will, in turn, significantly increase the encryption performance. Finally, a block permutation phase is accomplished by a permutation function to enhance the statistical performance of the proposed encryption approach. Conducted experiments based on various types of differential and statistical analyses show that the proposed encryption approach has high security, sensitivity and speed compared to previous approaches

QTL: A new ultra-lightweight block cipher

We propose a new ultra-lightweight block cipher, QTL. The 64 bits block cipher QTL supports 64 and 128 bits keys. To solve the slow diffusion of the traditional Feistel-type structures we have used a new variant of generalized Feistel network structure in design of the QTL. Traditional Feistel-type structures change only half of block messages in an iterative round, but our structure overcomes this disadvantage and changes all block messages. Thus, our structure has the fast diffusion of the Substitution Permutation Networks (SPNs) structures, which improves the security of lightweight block cipher in Feistel-type structures. Moreover, QTL algorithm has the same encryption and decryption processes, so it will occupy less area in resource-constrained applications. Furthermore, to reduce the cost of energy consumption in hardware implementation of the cipher while maintaining security, we decide not to use a key schedule. We show that QTL offers an adequate security level against classic analyses. Our hardware implementation for the 64 and the 128 bits keys modes only require 1025.52 and 1206.52 gate equivalents, respectively. QTL achieves high security and compact implementation in hardware. QTL is one of the most competitive ultra-lightweight block ciphers, which is suitable for extremely constrained devices.

New differentially 4-uniform permutations by modifying the inverse function on subfields

Permutations over ??22k$\mathbb {F}_{2^{2k}}$ with low differential uniformity, high algebraic degree and high nonlinearity are of great cryptographic importance since they can be chosen as the substitution boxes (S-boxes) for many block ciphers with SPN (Substitution Permutation Network) structure. A well known example is that the S-box of the famous Advanced Encryption Standard (AES) is derived from the inverse function on ??28$\mathbb {F}_{2^{8}}$, which has been proved to be a differentially 4-uniform permutation with the optimal algebraic degree and known best nonlinearity. Recently, Zha et al. proposed two constructions of differentially 4-uniform permutations over ??22k$\mathbb {F}_{2^{2k}}$, say Gt and Gs, t with Tr(s?1) = 1, by applying affine transformations to the inverse function on some subfields of ??22k$\mathbb {F}_{2^{2k}}$ (Zha et al. Finite Fields Appl. 25, 64---78, 2014). In this paper, we generalize their method by applying other types of EA (extended affine) equivalent transformations to the inverse function on some subfields of ??22k$\mathbb {F}_{2^{2k}}$ and present two new constructions of differentially 4-uniform permutations, say F? and Fs, ? with Tr(s?1) = 1. Furthermore, we prove that all the functions Gt with different t are CCZ (Carlet-Charpin-Zinoviev) equivalent to our subclass F0, while all the functions Gs, t with different t are CCZ-equivalent to our subclass Fs,0. In addition, both our two constructions give many new CCZ-inequivalent classes of such functions, as checked by computer in small numbers of variables. Moreover, all these newly constructed permutations are proved to have the optimal algebraic degree and high nonlinearity.

Impossible Differential Fault Analysis on the LED Lightweight Cryptosystem in the Vehicular Ad-Hoc Networks

With the advancement and deployment of leading-edge telecommunication technologies for sensing and collecting traffic related information, the vehicular ad-hoc networks (VANETs) have emerged as a new application scenario that is envisioned to revolutionize the human driving experiences and traffic flow control systems. To avoid any possible malicious attack and resource abuse, employing lightweight cryptosystems is widely recognized as one of the most effective approaches for the VANETs to achieve confidentiality, integrity and authentication. As a typical substitution-permutation network lightweight cryptosystem, LED supports 64-bit and 128-bit secret keys, which are flexible to provide security for the RFID and other highly-constrained devices in the VANETs. Since its introduction, some research of fault analysis has been devoted to attacking the last three rounds of LED. It is an open problem to know whether provoking faults at a former round of LED allows recovering the secret key. In this paper, we give an answer to this problem by showing a novel impossible differential fault analysis on one round earlier of all LED keysize variants. Mathematical analysis and simulating experiments show that the attack could recover the 64-bit and 128–bit secret keys of LED by introducing 48 faults and 96 faults in average, respectively. The result in this study describes that LED is vulnerable to a half byte impossible differential fault analysis. It will be beneficial to the analysis of the same type of other iterated lightweight cryptosystems in the VANETs.

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.

Substitution-Permutation Networks, Pseudorandom Functions, and Natural Proofs

This article takes a new step towards closing the gap between pseudorandom functions (PRF) and their popular, bounded-input-length counterparts. This gap is both quantitative, because these counterparts are more efficient than PRF in various ways, and methodological, because these counterparts usually fit in the substitution-permutation network paradigm (SPN), which has not been used to construct PRF. We give several candidate PRF F i that are inspired by the SPN paradigm. Most of our candidates are more efficient than previous ones. Our main candidates are as follows. — F 1 : {0,1} n → {0,1} n is an SPN whose S-box is a random function on b bits given as part of the seed. We prove that F 1 resists attacks that run in time ≤ 2 ϵb . — F 2 : {0,1} n → {0,1} n is an SPN where the S-box is (patched) field inversion, a common choice in practical constructions. We show that F 2 is computable with boolean circuits of size n ⋅ log O (1) n and that it has exponential security 2 Ω( n ) against linear and differential cryptanalysis. — F 3 : {0,1} n → {0,1} is a nonstandard variant on the SPN paradigm, where “states” grow in length. We show that F 3 is computable with TC 0 circuits of size n 1 + ϵ , for any ϵ > 0, and that it is almost 3-wise independent. — F 4 : {0,1} n → {0,1} uses an extreme setting of the SPN parameters (one round, one S-box, no diffusion matrix). The S-box is again (patched) field inversion. We show that F 4 is computable by circuits of size n ⋅ log O (1) n and that it fools all parity tests on ≤2 0.9 n outputs. Assuming the security of our candidates, our work narrows the gap between the Natural Proofs barrier and existing lower bounds in three models: circuits, TC 0 circuits, and Turing machines.

On Compact Cauchy Matrices for Substitution-Permutation Networks

Maximum distance separable (MDS) matrices are widely used in the design of block ciphers. However, it is highly nontrival to find MDS matrices which could be used in practice. This paper focuses on the design of efficient MDS matrices for substitution-permutation networks (SPNs). We provide a new method to construct and count these MDS matrices. Moreover, we identified an interesting class of Cauchy matrices (named compact Cauchy matrices) which has the fewest different entries and is thus more favorable for implementation. Finally, we prove that all compact Cauchy matrices could be modified into an involution compact Cauchy matrix, and show how to maximize the occurrences of entry “1” in a compact Cauchy matrix.

Properties of the Controlled Substitution-Permutation Network for Block Encryption Algorithm Based on One Class of Permutations

Article is devoted to investigation of the controlled substitution-permutation network based on managed elements F 4/2 as a primitive block encryption algorithms. Relevance of research is related to their focus on the design of high-speed hardware ciphers. The scientific and practical significance of the results is to improve the efficiency of high-speed hardware implementation of encryption algorithms, designed to protect information in information and telecommunication systems and networks.

Influence of addition modulo 2 n on algebraic attacks

Many modern ciphers have a substitution-permutation (SP) network as a main component. This design is well researched in relation to Advanced Encryption Standard (AES). One of the ways to improve the security of cryptographic primitives is the use of additional nonlinear layers. However, this replacement may not have any effect against particular cryptanalytic attacks. In this paper we use algebraic attacks to analyze an SP network with addition modulo 2n as the key mixing layer. In particular, we show how to reduce the number of intermediate variables in round functions based on SP networks. We also apply the proposed method to the GOST 28147-89 block cipher that allows us to break reduced 8- and 14-round versions with complexity at most 2155 and 2215.4, respectively.

ADVANCED FILE BASED SECURITY MECHANISM IN CLOUD COMPUTING: A REVIEW

Cloud computing is a broad solution that delivers IT as a service. Cloud computing uses the internet and the central remote servers to support different data and applications. It is an internet based technology. It permits the users to approach their personal files at any computer with internet access. The cloud computing flexibility is a function of the allocation of resources on authoritys request. It represents all the complexities of the network which may include everything from cables, routers, servers, data centers and all such other devices. Cloud based systems saves data off multiple organizations on shared hardware systems. In this paper the attempt to secure data from unauthorized access. The Method of data security is AES algorithm for providing data security by encrypting the given data based on the AES. It is based on a design principle known as a substitution-permutation network, and is fast in both Software and Hardware. The algorithms used in AES are so simple that they can be easily implemented using heap processors and a minimum amount of memory and this data then can only be decrypted by authorized person by using his private key.