Statistical analysis of the key scheduling of the new lightweight block cipher

This research paper is aimed at studying the generation of round keys (GRK) of the lightweight block cipher (LBC), which provides an optimal balance between security, performance, and minimal costs in internet of things (IoT). For comparative analysis, the GRK of the well-known PRESENT algorithm was studied. A number of studies have been carried out to assess the cryptographic strength of encryption algorithms, however, less attention has been paid to the assessment of the reliability of GRK algorithms, which can lead to a possible weakening of a cryptosystem. A trusted GRK should issue random and independent round keys regardless of the secret key. The experiments were carried out with secret keys of low and high density, as well as random numbers. The obtained results show that the GRK of the LBC algorithm generates random round keys that successfully pass tests of the National Institute of Standards and Technology (NIST) for randomness

Extended Substitution Cipher Chaining mode (ESCC)

In this paper, we present a new tweakable narrow-block mode of operation, the Extended Substitution Cipher Chaining mode (ESCC), that can be efficiently deployed in disk encryption applications. ESCC is an extention of Substitution Cipher Chaining mode (SCC)~\cite{scc}. Unlike SCC, ESCC is resistant to the attacks in~\cite{scc_attack,scc_attack2}

Key Generation Technique based on Triangular Coordinate Extraction for Hybrid Cubes

Cryptographic algorithms play an important role in information security where it ensures the security of data across the network or storage. The generation of Hybrid Cubes (HC) based on permutation and combination of integer numbers are utilized in the construction of encryption and decryption key in the non-binary block cipher. In this study, we extend the hybrid cube encryption algorithm (HiSea) and our earlier Triangular Coordinate Extraction (TCE) technique for HC by increasing the complexity in the mathematical approaches. We proposed a new key generation technique based on TCE for the security of data. In this regard, the Hybrid Cube surface (HCs) is divided into four quarters by the intersection of primary and secondary diagonal and each quarter is rotated by using the rotation points. The overall security of HC is improved by the rotation of HCs and enhanced the complexity in the design of key schedule algorithm. The brute force and entropy test are applied in experimental results which proved that the proposed technique is suitable for implementing a key generation technique and free from any predicted keys pattern

The Analysis of Galois Substitution Counter Mode (GSCM)

In~\cite{gscm}, GSCM mode of operation for authenticated encryption was presented. GSCM is based on the Galois/Counter Mode (GCM). GSCM is an enhancement of GCM, which is characterized by its high throughput and low memory consumption in network applications. In this paper, we propose some enhancements to GSCM and compare it with the different implementations of GCM. We present stability, performance, memory and security analyses of different implementations of GSCM and GCM

The LED Block Cipher

Abstract. We present a new block cipher LED. While dedicated to compact hardware implementation, and offering the smallest silicon footprint among comparable block ciphers, the cipher has been designed to simultaneously tackle three additional goals. First, we explore the role of an ultra-light (in fact non-existent) key schedule. Second, we consider the resistance of ciphers, and LED in particular, to related-key attacks: we are able to derive simple yet interesting AES-like security proofs for LED regarding related- or single-key attacks. And third, while we provide a block cipher that is very compact in hardware, we aim to maintain a reasonable performance profile for software implementation. Key words: lightweight, block cipher, RFID tag, AES.

On the Key Schedule of Lightweight Block Ciphers

Key schedules in lightweight block ciphers are often highly simplified, which causes weakness that can be exploited in many attacks. Today it remains an open problem on how to use limited operations to guarantee enough diffusion of key bits in lightweight key schedules. Also, there are few tools special for detecting weakness in the key schedule. In 2013 Huang et al. pointed out that insufficient actual key information (AKI) in computation chains is responsible for many attacks especially the meet-in-the-middle (MITM) attacks. Motivated by this fact, in this paper we develop an efficient (with polynomial time complexity) and effective tool to search the computation chains which involve insufficient AKI for iterated key schedules of lightweight ciphers. The effectiveness of this tool is shown by an application on TWINE-80. Then, we formulate the cause of key bits leakage phenomenon, where the knowledge of subkey bits is leaked or overlapped by other subkey bits in the same computation chain. Based on the interaction of diffusion performed by the key schedule and by the round function, a necessary condition is thus given on how to avoid key bits leakage. Therefore, our work sheds light on the design of lightweight key schedules by guiding how to quickly rule out unreasonable key schedules and maximize the security under limited diffusion

Tweaks and Keys for Block Ciphers: the TWEAKEY Framework

We propose the TWEAKEY framework with goal to unify the design of tweakable block ciphers and of block ciphers resistant to related-key attacks. Our framework is simple, extends the key-alternating construction, and allows to build a primitive with arbitrary tweak and key sizes, given the public round permutation (for instance, the AES round). Increasing the sizes renders the security analysis very difficult and thus we identify a subclass of TWEAKEY, that we name STK, which solves the size issue by the use of finite field multiplications on low hamming weight constants. We give very efficient instances of STK, in particular, a 128-bit tweak/key/state block cipher Deoxys-BC that is the first AES-based ad-hoc tweakable block cipher. At the same time, Deoxys-BC could be seen as a secure alternative to AES-256, which is known to be insecure in the related-key model. As another member of the TWEAKEY framework, we describe Kiasu-BC, which is a very simple and even more efficient tweakable variation of AES-128 when the tweak size is limited to 64 bits. In addition to being efficient, our proposals, compared to the previous schemes that use AES as a black box, offer security beyond the birthday bound. Deoxys-BC and Kiasu-BC represent interesting pluggable primitives for authenticated encryption schemes, for instance, OCB instantiated with Kiasu-BC runs at about 0.75 c/B on Intel Haswell. Our work can also be seen as advances on the topic of secure key schedule design for AES-like ciphers, describing several proposals in this direction

New Key Expansion Function of Rijndael 128-Bit Resistance to The Related-Key Attacks

A master key of special length is manipulated based on the key schedule to create round sub-keys in most block ciphers. A strong key schedule is described as a cipher that will be more resistant to various forms of attacks, especially in related-key model attacks. Rijndael is the most common block cipher, and it was adopted by the National Institute of Standards and Technology, USA in 2001 as an Advance Encryption Standard. However, a few studies on cryptanalysis revealed that a security weakness of Rijndael refers to its vulnerability to related-key differential attack as well as the related-key boomerang attack, which is mainly caused by the lack of nonlinearity in the key schedule of Rijndael. In relation to this, constructing a key schedule that is both efficient and provably secure has been an ongoing open problem. Hence, this paper presents a method to improve the key schedule of Rijndael 128-bit for the purpose of making it more resistance to the related-key differential and boomerang attacks. In this study, two statistical tests, namely the Frequency test and the Strict Avalanche Criterion test were employed to respectively evaluate the properties of bit confusion and bit diffusion. The results showed that the proposed key expansion function has excellent statistical properties and agrees with the concept of Shannons diffusion and confusion bits. Meanwhile, the Mixed Integer Linear Programming based approach was adopted to evaluate the resistance of the proposed approach towards the related-key differential and boomerang attacks. The proposed approach was also found to be resistant against the two attacks discovered in the original Rijndael. Overall, these results proved that the proposed approach is able to perform better compared to the original Rijndael key expansion function and that of the previous research

Методи побудови та дослідження властивостей малоресурсних блокових шифрів та їх компонентів

Дисертація присвячена розробці та удосконаленню методів аналізу криптографічних властивостей компонентів симетричних блокових шифрів та побудові перспективних криптографічних перетворень. Метою дисертаційної роботи є підвищення продуктивності симетричних криптографічних перетворень і удосконалення методів аналізу їх стійкості.Rodinko M. Yu. Methods of construction and research of properties of lightweight block ciphers and their components. – Qualification scholarly paper: a manuscript. Thesis submitted for obtaining the Doctor of Philosophy degree in Information Technologies, Speciality 122 – Computer Science. – V. N. Karazin Kharkiv National University, Ministry of Education and Science of Ukraine, Kharkiv, 2020. The dissertation is devoted to the development and improvement of methods on cryptographic properties analysis of block ciphers components and construction of perspective cryptographic transformations. The aim of the dissertation is to increase performance of symmetric cryptographic transformations and improve methods of analysis of their strength