Plaintext Block Research Articles

Design, analysis, and implementation of a new lightweight block cipher for protecting IoT smart devices

A modified XXTEA “M-XXTEA” symmetric block cipher that has a simple construction compared to the advanced encryption standard (AES) is proposed. It is efficient for protecting limited-resource devices such as IoT smart devices. The M-XXTEA will be able to achieve confidentiality during transmission of data over the internet. Since the original XXTEA was vulnerable against key-related and chosen-plaintext attacks. Therefore, this paper introduces a new and robust version of the original XXTEA by employing an improved S-box to enhance security to overcome such types of attacks. Besides, the M-XXTEA is coupled with a chaotic key generator system adding a layer of security achieving the idea behind the one-time pad. The cipher keys are dynamically changing for each block of plaintext when encrypted. Thus, it provides a more robust security mechanism than the original XXTEA and the AES. Besides enhancing data security, the M-XXTEA can function with different sizes of text blocks and with different key sizes. Several experiments are implemented to compare the performance of the M-XXTEA with the original XXTEA and with the AES. Results show that the M-XXTEA encryption and decryption time efficiencies outperform AES by 60%. Besides, the M-XXTEA achieves speed efficiency 57% better than the AES. It can be used efficiently for protecting IoT smart devices in the industry, and e-health systems, and smart cities.

Efficient Security Algorithm for Power-Constrained IoT Devices

Internet-of-Things (IoT) devices characterized by low power and low processing capabilities do not exactly fit into the provision of existing security techniques due to their constrained nature. Classical security algorithms that are built on complex cryptographic functions often require a level of processing that low-power IoT devices are incapable to effectively achieve due to limited power and processing resources. Consequently, the option for constrained IoT devices lies in either developing new security schemes or modifying existing ones to be more suitable for constrained IoT devices. In this work, an efficient security algorithm for constrained IoT devices, based on the advanced encryption standard, is proposed. We present a cryptanalytic overview of the consequence of complexity reduction together with a supporting mathematical justification, and provisioned a secure element (ATECC608A) as a tradeoff. The ATECC608A doubles for authentication and guarding against implementation attacks on the associated IoT device (ARM Cortex M4 micro-processor) in line with our analysis. The software implementation of the efficient algorithm for constrained IoT devices shows up to 35% reduction in the time it takes to complete the encryption of a single block (16 B) of plain text, in comparison to the currently used standard AES-128 algorithm, and in comparison to current results in literature at 26.6%.

From Combined to Hybrid: Making Feedback-based AE even Smaller

In CHES 2017, Chakraborti et al. proposed COFB, a rate-1 sequential block cipher-based authenticated encryption (AE) with only 1.5n-bit state, where n denotes the block size. They used a novel approach, the so-called combined feedback, where each block cipher input has a combined effect of the previous block cipher output and the current plaintext block. In this paper, we first study the security of a general rate-1 feedback-based AE scheme in terms of its overall internal state size. For a large class of feedback functions, we show that the overlying AE scheme can be attacked in 2r queries if the internal state size is n + r bits for some r ≥ 0. This automatically shows that a birthday bound (i.e. 2n/2 queries) secure AE scheme must have at least 1.5n-bit state, whence COFB is almost-optimal (use 1.5n-bit state and provides security up to 2n/2/n queries). We propose a new feedback function, called the hybrid feedback or HyFB, which is a hybrid composition of plaintext and ciphertext feedbacks. HyFB has a key advantage of lower XOR counts over the combined feedback function. This essentially helps in reducing the hardware footprint. Based on HyFB we propose a new AE scheme, called HyENA, that achieves the state size, rate, and security of COFB. In addition, HyENA has significantly lower XOR counts as compared to COFB, whence it is expected to have a smaller implementation as compared to COFB.

DNA Cryptographic System Utilizing Random Permutation

The study of encryption/decryption of information is known as cryptography. The need of protecting information from old years until now is the reason of appearing the process of hiding information from unauthorized people to access it. In this research paper, a cryptographic system is designed by using the DNA computing concepts and random permutation. The proposed system is a block symmetric cipher that uses one initial key in which will be used to generate permutations as many as needed, convert the initial key to DNA key, convert plaintext block to DNA bases. The remaining needed DNA keys are produced through the cipher/deciphering processing. Different operations applied: permute using permutation, modulo and XOR operations to perform the encryption/decryption process. Using the DNA based cryptography enhance the information security and produce highly efficient cipher systems.

KBC: Multiple Key Generation using Key Block Chaining

Cryptography is an important aspect of securing communications, however, the encryption scheme may be known to the attacker(s). Hence, the key can be rewarded as a crucial part of any cryptographic algorithm. With the symmetric key, researchers have developed chaining concepts where the output of one operation becomes an input to the next one. Such concept of modes of operation (Cipher Block Chaining) is integrated in this article to generate multiple key blocks. The generated keys can be provided to an individual block of plaintext for any encryption technique as per the requirements. The proposed Key Block Chaining (KBC) approach can also be referred to as a key derivation approach. The basic concepts of Advanced Encryption Standard and Message Authentication Code have also been incorporated in the proposed model to introduce randomness, and thereby, ensuring security as well as robustness. To assess the randomness of the sequence of generated keys, KBC is implemented and tested using the National Institute of Standards and Technology statistical test suite and reasonable randomness has been successfully achieved. Possible variations and key points of the proposed approach along with statistical analysis and significance of our work have been discussed.

Partial Image Encryption Using Cellular Automata

In this work is proposed a partial image encryption method based on the synchronization of the cellular automaton rule 90. The security analysis proves that this cryptosystem is resistant to different tests and attacks such as the Chosen/Knownplain image attack and bit-replacement. This algorithm is a variant from another encryption algorithm named ESCA, in this case we modified the ESCA system to a partial encryption version reducing the latency time up to a 50%. This version has two changes a)it only encrypts the three most significant bits, and b) the bits of the secret key are rotated instead of calculating a key for each block of plaintext. These changes allow to reduce the latency time and according to the tests do not compromise the security. This proposal could be a feasible and secure option for real-time applications.

“S-Box” Implementation of AES Is Not Side Channel Resistant

Several successful cache-based attacks have provided strong impetus for developing side channel resistant software implementations of AES. One of the best-known countermeasures—use of a “minimalist” 256-byte look-up table—has been employed in the latest (assembly language) versions. Software and hardware pre-fetching and out-of-order execution in modern processors have served to further shrink the attack surface. Despite these odds, we devise and implement two strategies to retrieve the complete AES key. The first uses adaptively chosen plaintext and random plaintext in a 2-round attack. The second strategy employs only about 50 blocks of random plaintext in a novel single round attack. The attack can be extended to spying on table accesses during decryption in a ciphertext-only attack. We also present an analytical model to explain the effect of false positives and false negatives and capture various practical tradeoffs involving number of blocks of plaintext, offline computation time for key retrieval and success probability.

Modified Encryption Standard with High Performance through Secure Protocol

The Advanced Encryption Standard (AES) has been accepted worldwide as a desirable algorithm to encryption and decryption sensitive information. In cryptography the unencrypted information referrers to as plaintext it is encrypted into cipher-text, which will in turn be decrypted back into the usable plaintext. The encryption and decryption are based on the type of cryptography system and secret keys. The secret key is responsible for preparing the input key to be used by the cipher in each round. AES with one-stage pipeline producing minor reduction of delay but does not show any improvement in area and power consumption. To overcome the above drawbacks, the basic architecture of AES, which includes encryption and decryption can be modified with one stage pipeline architecture by using one- dimensional Substitute Box (SBOX). Advanced Microcontroller Bus Architecture (AMBA) describes level of an on-chip communication standards for elevated performance embedded microcontrollers. AMBA AHB (Advanced High Performance Bus) is intended for elevated performance and high-frequency clocks. AHB has unique characteristics such as burst transfer, split transaction and single-cycle master bus transfer. 128 bit plain text is guided by AMBA-AHB requirements and can be used to send a plain text block to the cypher per clock cycle.. Plain text of 128 bit is driven by AMBA-Advanced High-performance Bus. AMBA-AHB specifications and supports the transmission to the cipher of a plain text block per clock cycle i.e., Modified Encryption Standard will be implemented with AMBA –AHB driven by input, which provides on-chip communication, increasing security of encryption standard. Propositioning methodology, Modified Encryption Standard will be simulated and synthesized by using Xilinx ISim 14.7 FPGA.

4216 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: A1622109119/2019©BEIESP DOI: 10.35940/ijeat.A1622.109119 Journal Website: www.ijeat.org El Gamal Encryption using Lucas, Elliptic Curve and SRZ Model

In cryptography, the security is depending on the way in which it produces different ciphertexts for the same plaintext so that the eavesdropper is not able to recover the plaintext from the ciphertext. Though, several block cipher modes viz., CBC, CFB and OFB exist, they take more time for producing different ciphertext blocks for the same plaintext block. To avoid this, an encoding is performed at the plaintext level. There are several encoding schemes like ASCII, Magic Square, and Magic Rectangle based encoding exist in the literature. But, in this paper, a novel encoding technique based on Elliptic Curve, Lucas number, Spiral Clockwise Rotation and Zigzag transformations called ECLUSRZ has been proposed. As, the original form of plaintext is completely altered using this proposed encoding scheme, the eavesdropper may not easily recover the plaintext from the ciphertext. Once, the encoding is performed , the encoded numeral called intermediate plaintext is then used for any one of the public key cryptosystems like ElGamal and the security level produced by ElGamal encryption with ASCII based and the proposed ECLUSRZ based encoding is analyzed.

Designing and Implementing FPGA for AES

The execution of DES and triple DES is not possible on hardware platform because they consume huge memory space. We can use field programmable gate arrays in order to do the hardware implementation because of its low charge, advertising space and reconfiguration nature. This paper aims at reducing the delay by using pipeline for speeding up the process. The proposed pipeline structure has a characteristic of having round keys which during iterations of encryption are utilized and an encryption method is used for generating them in parallel. The overall delay related to a delay of coding of plaintext block is reduced. The simulation is done in VHDL by Xilinx and implementation is done on FPGA Spartan 3E.

Применение атаки различения на легковесные блочные шифры, основанные на ARX-операциях

Рассмотрено применение атаки различения на ряд легковесных блочных шифров, основанных на ARX-операциях (сложение по модулю, циклический сдвиг и исключающее ИЛИ). Представлены экспериментальные результаты и теоретические оценки устойчивости легковесных шифров Speck, Simon, Simeck, HIGHT, LEA к атаке различения. Вывод, что семейство шифров Simeck не выдерживает эту атаку, сделан на основе прогнозов, полученных путем экстраполяции экспериментальных данных. The distinguishing attack on modern lightweight ARX-based block ciphers was applied. Distinguishing attack is any form of cryptanalysis on data encrypted by a cipher that allows an attacker distinguishing the encrypted data from random data. Purpose. Modern symmetric-key ciphers must be designed to be immune to such an attack. The purpose of the work was to estimate the resistance of lightweight ciphers Speck, Simon, Simeck, HIGHT, and LEA to a distinguishing attack. Methodology. We note that these ciphers are iterated block ciphers. It is means that they transform blocks of plain text into blocks of cipher text by using the cyclically repeated invertible function known as the round function where each iteration is to be referred as a round. We have experimentally found a maximum number of rounds where encrypted data looked like random bit-sequence by using statistical test “Book Stack”. Then we extrapolated the theoretical length required for a successful distinguishing attack on cipher with full-number rounds by a polynomial of a low degree. Note that cryptography attack is considered as successful if the length of the encrypted sequence is less than the length 2K (K — key size). Originality/value. Our experiments and estimations show, that Simeck with 48bit block size and 96-bit key size is not immune to distinguishing attack. We recommended increasing the number of rounds by 15–20% in order to improve the reliability of the Simeck 48/96.

Multilayer neural network synchronized secured session key based encryption in wireless communication

In this paper, multilayer neural network synchronized session key based encryption has been proposed for wireless communication of data/information. Multilayer perceptron transmitting systems at both ends accept an identical input vector, generate an output bit and the network are trained based on the output bit which is used to form a protected variable length secret-key. For each session, different hidden layer of multilayer neural network is selected randomly and weights or hidden units of this selected hidden layer help to form a secret session key. The plain text is encrypted through chaining , cascaded xoring of multilayer perceptron generated session key. If size of the final block of plain text is less than the size of the key then this block is kept unaltered. Receiver will use identical multilayer perceptron generated session key for performing deciphering process for getting the plain text. Parametric tests have been done and results are compared in terms of Chi-Square test, response time in transmission with some existing classical techniques, which shows comparable results for the proposed technique.

Notice of Retraction Coupled Tree Parity Machines: Synchronized Secured Session Key based Encryption in Online Transaction

Notice of Retraction-----------------------------------------------------------------------After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of APTIKOM's Publication Principles.We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.The presenting author of this paper has the option to appeal this decision by contacting ij.aptikom@gmail.com.----------------------------------------------------------------------- In this paper, tree parity synchronized session key validation followed by encryption has been proposed for online data communication. Tree Parity Machine transmitting systems at both ends accepted an identical input vector, generated an output bit, validated the weight vector and the networks were trained accordingly based on the output bit which was used to form a protected variable length secret key. Existence of a better degree of coupling between the two topological same tree parity machines has been reflected in this paper. Instead of sharing the entire weight vector, the proposed technique guided the partial transmission and validation of session key. A string of sub key has been derived from the synchronized session key for initial ciphering matrix. The plain text was encrypted through single columnar transposition ciphering at first round of encryption followed by successive cascaded XORing of TPM generated session key. If size of the final block of plain text was less than the size of the key then this block was treated unaltered. Recipient used identical generated session key for performing deciphering process for getting the plain text. Brute force attacks analysis has been implemented which determines a higher amount of time to decrypt by the intruders. Such long computational operations were not feasible by any of randomly selected fast networks at the intruders’ terminals.

Perancangan Aplikasi Kriptografi Asimetris Dengan Menerapkan Metode Elliptic Curve Cryptography

Cryptography is one of the sciences used to maintain confidentiality and data security has been developing since ancient Greece. One cryptographic method that is quite reliable, stable and the parent of the popular cryptographic algorithms today is Elliptic Curve Cryptography (ECC). In this case the previous block encryption results are feedback into current block encryption. The trick, the current plaintext block is XORed first with the ciphertext block from the previous encryption, then the XOR results are entered into the encryption function. With ECC mode, each ciphertext block depends not only on the plaintext block but also on the all previous plaintext blocks, Implementation of the Elliptic Curve Cryptography (ECC) algorithm in this study was carried out by using an application built using visual basic programming language. Net 2008..

Separable Statistics and Multidimensional Linear Cryptanalysis

Multidimensional linear cryptanalysis of block ciphers is improved in this work by introducing a number of new ideas. Firstly, formulae is given to compute approximate multidimensional distributions of the encryption algorithm internal bits. Conventional statistics like LLR (Logarithmic Likelihood Ratio) do not fit to work in Matsui’s Algorithm 2 for large dimension data, as the observation may depend on too many cipher key bits. So, secondly, a new statistic which reflects the structure of the cipher round is constructed instead. Thirdly, computing the statistic values that will fall into a critical region is presented as an optimisation problem for which an efficient algorithm is suggested. The algorithm works much faster than brute forcing all relevant key bits to compute the statistic. An attack for 16-round DES was implemented. We got an improvement over Matsui’s attack on DES in data and time complexity keeping success probability the same. With 241.81 plaintext blocks and success rate 0.83 (computed theoretically) we found 241.46 (which is close to the theoretically predicted number 241.81) key-candidates to 56-bit DES key. Search tree to compute the statistic values which fall into the critical region incorporated 245.45 nodes in the experiment and that is at least theoretically inferior in comparison with the final brute force. To get success probability 0.85, which is a fairer comparison to Matsui’s results, we would need 241.85 data and to brute force 241.85 key-candidates. That compares favourably with 243 achieved by Matsui.

Separable Statistics and Multidimensional Linear Cryptanalysis

Multidimensional linear cryptanalysis of block ciphers is improved in this work by introducing a number of new ideas. Firstly, formulae is given to compute approximate multidimensional distributions of the encryption algorithm internal bits. Conventional statistics like LLR (Logarithmic Likelihood Ratio) do not fit to work in Matsui’s Algorithm 2 for large dimension data, as the observation may depend on too many cipher key bits. So, secondly, a new statistic which reflects the structure of the cipher round is constructed instead. Thirdly, computing the statistic values that will fall into a critical region is presented as an optimisation problem for which an efficient algorithm is suggested. The algorithm works much faster than brute forcing all relevant key bits to compute the statistic. An attack for 16-round DES was implemented. We got an improvement over Matsui’s attack on DES in data and time complexity keeping success probability the same. With 241.81 plaintext blocks and success rate 0.83 (computed theoretically) we found 241.46 (which is close to the theoretically predicted number 241.81) key-candidates to 56-bit DES key. Search tree to compute the statistic values which fall into the critical region incorporated 245.45 nodes in the experiment and that is at least theoretically inferior in comparison with the final brute force. To get success probability 0.85, which is a fairer comparison to Matsui’s results, we would need 241.85 data and to brute force 241.85 key-candidates. That compares favourably with 243 achieved by Matsui.

Substitution box generation using Chaos: An image encryption application

There are procedures to encrypt images; however, sometimes there is a loss of information in the decryption process or the key set size is not specifically mentioned. In this research, substitution boxes are built for the Advanced Encryption Standard (AES) cryptosystem using Chaos, and generated by a non-linear differential equation. The boxes’ non-linearity is quantified using the Walsh function. One thousand twenty four boxes are chosen with a non-linearity of 106. To generate a pseudorandom permutation over 256 elements, an algorithm that defines a bijective function is employed. The AES utilized in this article uses 128 bit keys and applies a box in each round; that is, using an array of 10 boxes for each plaintext block of 128 bits. An encryption application for color images is presented. The degree of the encrypted images’ randomness is measured to quantify the cipher quality. Image encryption is performed without information loss. The aim in future is to design a device to encrypt video in a robust manner and in real time without loss of information.

Randomness Analysis of DES Ciphers Produced with Various Dynamic Arrangements

Over the past few years, researchers have devoted efforts to enhance the original DES encryption algorithm. These enhancements focus on improving multiple perspectives of the algorithm through enhancing its internal components to deliver a robust DES variant against different kinds of typical attacks such as linear and differential crypto analysis, in addition to the newly evolved attacks such as differential power analysis attacks. In fact the output of existing solutions have enhanced the ciphertext randomness. This paper introduces two encryption algorithms that enhance the original DES named DDES and HDES. DDES is mainly based on a secure selection of both S-boxes and P-box arrangements during each encryption round, it has also extended the key length by adding two more keys beside the original one to the encryption process. HDES, on the other hand, uses a hash function to generate a random fingerprint for each plaintext block. This fingerprint is used to generate the seed to produce round seeds that are used to select secure S-boxes only for each round in the encryption process. These two variants meet with certain demands that are imposed by the user applications context. DDES provides a higher ciphertext randomness with some added processing time, while HDES provides a relatively secure variant with lower processing time. These two variants can provide alternatives depending on the targeted applications that require different levels of security and processing time. DDES and HDES have been evaluated and compared against DES, DESX and 3DES, using a number of metrics including chi-square test, cipher data difference, hamming distance and processing time.

Turning Online Ciphers Off

CAESAR has caused a heated discussion regarding the merits of one-pass encryption and online ciphers. The latter is a keyed, length preserving function which outputs ciphertext blocks as soon as the respective plaintext block is available as input. The immediacy of an online cipher affords a clear performance advantage, but it comes at a price: ciphertext blocks cannot depend on later plaintext blocks, limiting diffusion and hence security. We show how one can attain the best of both worlds by providing provably secure constructions, achieving full cipher security, based on applications of an online cipher around blockwise reordering layers. Explicitly, we show that with just two calls to the online cipher, prp security up to the birthday bound is both attainable and maximal. Moreover, we demonstrate that three calls to the online cipher suffice to obtain beyond birthday bound security. We provide a full proof of this for a prp construction, and, in the ±prp setting, security against adversaries who make queries of any single length. As part of our investigation, we extend an observation by Rogaway and Zhang by further highlighting the close relationship between online ciphers and tweakable blockciphers with variable-length tweaks.

Turning Online Ciphers Off

CAESAR has caused a heated discussion regarding the merits of one-pass encryption and online ciphers. The latter is a keyed, length preserving function which outputs ciphertext blocks as soon as the respective plaintext block is available as input. The immediacy of an online cipher affords a clear performance advantage, but it comes at a price: ciphertext blocks cannot depend on later plaintext blocks, limiting diffusion and hence security. We show how one can attain the best of both worlds by providing provably secure constructions, achieving full cipher security, based on applications of an online cipher around blockwise reordering layers. Explicitly, we show that with just two calls to the online cipher, prp security up to the birthday bound is both attainable and maximal. Moreover, we demonstrate that three calls to the online cipher suffice to obtain beyond birthday bound security. We provide a full proof of this for a prp construction, and, in the ±prp setting, security against adversaries who make queries of any single length. As part of our investigation, we extend an observation by Rogaway and Zhang by further highlighting the close relationship between online ciphers and tweakable blockciphers with variable-length tweaks.