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Rapid technological developments have also affected the countries of the Balkans, where as a result many hackers and other attackers have attempted to attack computer systems and data in these countries as well. The initial attacks that directed you to these places were "phishing" attacks where there was an attempt to suspend the work of online systems, especially in Public Institutions. But over time, especially in the last 3 years, the biggest attacks belong to DDoS attacks, which have caused many problematic situations and an instability of the systems in these countries. Cyber ​​attacks are normal in the era we live in now, but the reasons for these attacks still vary from the most diverse, such as: political blackmail, blackmail of other kinds or even blackmail for monetary benefits. Our research considers 7 countries of the Balkans: Kosovo, North Macedonia, Albania, Serbia, Montenegro, Bosnia and Herzergovina, and Croatia. The main analysis focuses on the treatment of policies to protect against cyber attacks and strategies that these countries have with the aim of protecting against cyber attacks, which were on a large scale during the last period. All data has been collected during real time and the countries are ranked according to the level of exposure to the risk. The purpose of this research is to know the current situation in the Balkans and to identify the types of attacks directed at these countries, also some investigations into the current strategies have been proposed. The paper uses methods of analysis and synthesis, comparative methods, as well.

The latest research shows the benefits, the impact, and the usage of Blockchain and decentralized systems with a high confidence. Its popularity becomes even higher with the electronic voting systems based on the technology itself. In this paper we propose a new implementation of an electronic voting system based on Blockchain using ECDSA with blind signatures. Additionally, the system is compared with other electronic voting systems based on Blockchain technology. Mainly these types of systems hardly ever fulfill the scalability. Nevertheless, our system has an advantage in comparison with the other systems. Since the idea of the Blockchain technology is to show the flexibility and equal privileges to all nodes, this implementation with Angular and Spring Boot shows that, so everyone can track the chain. To sum up, this implementation can have a good usage in smaller departments, because of the performances and all mathematical operations.

The DICOM (Digital Imaging and COmmunication in Medicine) standard provides a framework for a diagnostically-accurate representation, processing, transfer, storage and display of medical imaging data. Information hiding in DICOM is currently limited to the application of digital media steganography and watermarking techniques on the media parts of DICOM files, as well as text steganographic techniques for embedding information in metadata of DICOM files. To improve the overall security of the DICOM standard, we investigate its susceptibility to network steganographic techniques. To this aim, we develop several network covert channels that can be created by using a specific transport mechanism – the DICOM Message Service and Upper Layer Service. The bandwidth, undetectability and robustness of the proposed covert channels are evaluated, and potential countermeasures are suggested. Moreover, a detection mechanism leveraging entropy-based metrics is introduced and its performance has been assessed.

A groupoid is an algebraic structure (G,*) formed by a non-empty set G and a binary function *: G2 → G defined on the set G. A groupoid that has finite number of elements is called finite groupoid. The number of finite groupoids of not so big order is huge and that implies the needs of their classifications. This paper will give some classifications of groupoids of order 3, the number of them is 19.683, by using suitably defined image patterns.

The increasing application of ICT technologies to medicine opens new usage patterns. Among the various standards, the Digital Imaging and COmmunication in Medicine (DICOM) has been gaining momentum, mainly due to its complete coverage of the diagnostic pipeline, including key applications such as CT, MRI and ultrasound scanners. However, owing to its complex and multifaceted nature, DICOM is prone to many risks especially due to the vast and complex attack surface characterizing the composite interplay of services, formats and technologies at the basis of the standard. Luckily, DICOM exhibits some room for improving its security. Specifically, information hiding and steganography can be used in a twofold manner. On one hand, they can help to watermark diagnostic images to improve their resistance against tampering and alterations. On the other hand, the digital infrastructure at the basis of DICOM can lead to data leaks or malicious manipula- tions via artificial intelligence techniques. Therefore, in this work we introduce risks and opportunities when applying information- hiding-based techniques to the DICOM standard. Our investigation highlights some opportunities as well as introduces possibilities of exploiting DICOM images to set up covert channels, i.e., hidden communication paths that can be used to exfiltrate data or launch attacks. To prove the effectiveness of our vision, this paper also showcases the performance evaluation of a covert channel built by applying text steganography principles on realistic DICOM images.

Random codes based on quasigroups (RCBQ) are cryptcodes, i.e. they are error-correcting codes, which provide information security. Cut-Decoding and 4-Sets-Cut-Decoding algorithms for these codes are defined elsewhere. Also, the performance of these codes for the transmission of text messages is investigated elsewhere. In this study, the authors investigate the RCBQ's performance with Cut-Decoding and 4-Sets-Cut-Decoding algorithms for transmission of images and audio files through a Gaussian channel. They compare experimental results for both coding/decoding algorithms and for different values of signal-to-noise ratio. In all experiments, the differences between the transmitted and decoded image or audio file are considered. Experimentally obtained values for bit-error rate and packet error rate and the decoding speed of both algorithms are compared. Also, two filters for enhancing the quality of the images decoded using RCBQ are proposed.

As machine learning is used to analyse data and produce some action based on that data, the application in the domain of cryptanalysis opens new points of view, since the key space of any complex cipher system is large. When concerning machine learning with the algorithms of cryptography, the possibility to learn from the experience that is provided by information retrieval, is being considered. With the understanding that cryptanalysis can be used for improvement and producing more complex solutions in the field of cryptography, common features are sought between these three fields. This paper aims to present the application of machine learning in the field of cryptanalysis, as a prime step for auditing and checking the strength of cryptosystems. Some of these cryptosystems ensure confidentiality and security of a variety of information exchanged from source to destination using symmetric key cryptography. Accordingly, understanding how the algorithms are maintaining the stability is the fundamental aspect for proceeding with the analysis. The experimental part of this paper provides a solution for application of neural networks in cryptanalysis. We show that AES with ECB mode is vulnerable to ciphertext-plaintext attacks. The analysis is focused on trying different sizes of keys for obtaining the ciphertexts from plaintexts. At the end, we discuss how that is impacting the difficulty of data reveal by decrypting with DNN (Artificial Neural Network).

The main objective of this chapter is to offer to practitioners, researchers and all interested parties a brief categorized catalog of existing lightweight symmetric primitives with their main cryptographic features, ultimate hardware performance, and existing security analysis, so they can easily compare the ciphers or choose some of them according to their needs. Certain security evaluation issues have been addressed as well. In particular, the reason behind why modern lightweight block cipher designs have in the last decade overwhelmingly dominated stream cipher design is analyzed in terms of security against tradeoff attacks. It turns out that it is possible to design stream ciphers having much smaller internal states.

Blockchain is a growing list of linked blocks. Since each participant stores the whole list of transactions, the storage space rapidly increases. Therefore, there is a need of changing the storage concept in blockchain. There are several solutions for this problem based on network coding and secret sharing. In this paper, we propose a novel use of Shamir's secret sharing scheme for reducing the storage cost in blockchain system.

Bitcoin and Smart Contract are the first major applications of the BlockChain technology. But, with increasing the number of transactions, the process of verification on every transaction is very slow. This is the reason for a third major innovation called a BlockChain scaling. The scalability is a process of taking certain steps in accelerating the performing of transactions in this new technology. In this paper we analyze the possibilities for BlockChain scalability and we examine the advantages and disadvantages of the proposed solutions.

We present several new observations on the CAESAR candidate MORUS (v1). First, we report a collision on its \(\mathrm {StateUpdate}(S, M)\) function. Second, we describe a distinguisher in a nonce-reuse scenario with probability 1. Finally, we observe that the differences in some words of the state after the initialization have probabilities significantly higher than the random case. We note that the presented results do not threaten the security of the scheme. This is the first external analysis of the authenticated cipher MORUS.

Pseudo random sequence generators (PRSG) produce sequences of elements that imitate natural random behavior and they have extensive applications in many fields like cryptography, authentication and cryptanalysis. Using quasigroup string transformations, a PRSG is introduced in [1]. Here, we propose a new design of PRSG using parastrophic quasigroup transformation defined in [2]. This generator is called Parastrophic Quasigroup Pseudo Random Sequence Generator (PQPRSG). We investigate the goodness of quasigroups of order 4 for designing of PQPRSQG using classifications given in [3] and linearity of quasigroups defined in [4]. At the end, we give experimental results about the period of the generator.

The resistance to statistical kind of attacks of encrypted messages is a very important property for designing cryptographic primitives. In this paper, the parastrophic quasigroup PE-transformation, proposed elsewhere, is considered and the proof that it has this cryptographic property is given. Namely, it is proven that if PE-transformation is used for design of an encryption function then after n applications of it on arbitrary message the distribution of m-tuples (m = 1; 2; : : : ; n) is uniform. These uniform distributions imply the resistance to statistical attack of the encrypted messages. For illustration of theoretical results, some experimental results are presented as well.

Quasigroups are algebraic structures that are suitable for cryptographic use and their cryptographic properties are intriguing. Looking into these properties we can classify the quasigroups based on different criteria and sort out the ones with best attributes for encryption and resistance to attacks. The Boolean representations of quasigroups allow us to find out more about their cryptographic properties. Some of them are already examined and determined. In this research we will use some previous conclusions in order to find out more about the cryptographic properties of the sets of parastrophic quasigroups.

Quasigroup string transformations are already used for designing of several cryptographic primitives. The application of quasigroup transformations as encryption algorithm is based on the previously proved result: the distribution of m-tuples in arbitrary string processed by application of quasigroup E (n)-transformation is uniformly distributed for m ≤ n. In this paper, we give some probabilistic properties of quasigroup processed strings that can be used in cryptanalysis. Namely, we find the distribution of m-tuples in an arbitrary string processed by application of quasigroup E (n)-transformation (m > n). Since this distribution is not uniform, it can be used for statistical attack in order to discover the original message and we give an algorithm for this kind of attack. Suitable experimental results are presented as well.

In this short note we represent quasigroups of order 2 n as vector valued Boolean functions f:{0,1}2n →{0,1} n . The representation of finite quasigroups as vector valued Boolean functions allows us systems of quasigroup equations to be solved by using Grobner bases.