Genetic algorithms in cryptography

Genetic algorithms (GAs) are a class of optimization algorithms. GAs attempt to solve problems through modeling a simplified version of genetic processes. There are many problems for which a GA approach is useful. It is, however, undetermined if cryptanalysis is such a problem. Therefore, this work explores the use of GAs in cryptography. Both traditional cryptanalysis and GA-based methods are implemented in software. The results are then compared using the metrics of elapsed time and percentage of successful decryptions. A determination is made for each cipher under consideration as to the validity of the GA-based approaches found in the literature. In general, these GA-based approaches are typical of the field. Of the genetic algorithm attacks found in the literature, totaling twelve, seven were re-implemented. Of these seven, only three achieved any success. The successful attacks were those on the transposition and permutation ciphers by Matthews [20], Clark [4], and Griindlingh and Van Vuuren [13], respectively. These attacks were further investigated in an attempt to improve or extend their success. Unfortunately, this attempt was unsuccessful, as was the attempt to apply the Clark [4] attack to the monoalphabetic substitution cipher and achieve the same or indeed any level of success. Overall, the standard fitness equation genetic algorithm approach, and the scoreboard variant thereof, are not worth the extra effort involved. Traditional cryptanalysis methods are more successful, and easier to implement. While a traditional method takes more time, a faster unsuccessful attack is worthless. The failure of the genetic algorithm approach indicates that supplementary research into traditional cryptanalysis methods may be more useful and valuable than additional modification of GA-based approaches

Cyber Security- A New Secured Password Generation Algorithm with Graphical Authentication and Alphanumeric Passwords Along With Encryption

Graphical passwords are always considered as an alternative of alphanumeric passwords for their better memorability and usability [1]. Alphanumeric passwords provide an adequate amount of satisfaction, but they do not offer better memorability compared to graphical passwords [1]. On the other hand, graphical passwords are considered less secured and provide better memorability [1]. Therefore many researchers have researched on graphical passwords to overcome the vulnerability. One of the most significant weaknesses of the graphical passwords is Shoulder Surfing Attack, which means, sneaking into a victim\u27s computer to learn the whole password or part of password or some confidential information. Such kind of attacks is called as Shoulder Surfing Attack. Many researchers have presented various ideas to curb the shoulder surfing attack. However, graphical passwords are still vulnerable to this attack. Therefore, in the present thesis, the solution for shoulder surfing attack is analyzed and a new algorithm is developed to provide better algorithm with memorability as well as very strong password using the encryption. For alphanumeric passwords, dictionary attack, and brute force attack are critical potential threats to be taken care off. Dictionary attacks mean, attacking every word from the dictionary to crack the password, whereas, brute force attack means, applying all different kind of combinations to crack the password. Thus, both protection methods have their pros and cons and, therefore in this thesis, the possible solution has been researched to provide more secure technique. Encryption is another essential technique in the field of cybersecurity. The history of encryption dates back to World War 2, where German forces used its encryption technique for the first time, and this encryption has been developed a lot with the consistent contribution of many researchers. Starting from the German encryption technique, the present encryption field has evolved a lot and compared to its primitive form; the current encryption techniques are more secured. In the encryption, various cryptosystems have been developed, and due to consistently developed computational power, attackers have compromised various cryptosystem. One of the essential cryptosystems is the MD family cryptosystem. In the MD family, a few members have been compromised whereas members such as MD5, had inbuilt algorithm flow and therefore they became vulnerable for different reasons. In this thesis, the research has been done with Whirlpool encryption, which is never compromised as of now. However, before using the Whirlpool encryption, the string has been processed with multiple steps, such as, perception, shifting of characters, splitting the string into chunks, and then each piece has been encrypted to populate 128 characters long password for each fragment and thus, the algorithm to generate 1280 characters long passwords is proposed which are immune to linear attacks, dictionary attacks, brute force attacks, and shoulder surfing attack. After the research, the computational time is also calculated for the modern computer (8 core, 2.8 GHz) as well as the present Supercomputers which are 100000 times faster than a modern computer. After all the research, the conclusion and future work are also mentioned for future research

A Covert Encryption Method for Applications in Electronic Data Interchange

A principal weakness of all encryption systems is that the output data can be ‘seen’ to be encrypted. In other words, encrypted data provides a ‘flag’ on the potential value of the information that has been encrypted. In this paper, we provide a new approach to ‘hiding’ encrypted data in a digital image. In conventional (symmetric) encryption, the plaintext is usually represented as a binary stream and encrypted using an XOR type operation with a binary cipher. The algorithm used is ideally designed to: (i) generate a maximum entropy cipher so that there is no bias with regard to any bit; (ii) maximize diffusion in terms of key dependency so that a change in any bit of the key can effect any, and potentially all, bits of the cipher. In the work reported here, we consider an approach in which a binary or low-bit plaintext image is encrypted with a decimal integer or floating point cipher using a convolution operation and the output quantized into a 1-bit array generating a binary image ciphertext. This output is then ‘embedded’ in a host image to hide the encrypted information. Embedding is undertaken either in the lowest 1-bit layer or multiple 1-bit layers. Decryption is accomplished by: (i) extracting the binary image from the host image; (ii) correlating the result with the original cipher. In principle, any cipher generator can be used for this purpose and the method has been designed to operate with 24-bit colour images. The approach has a variety of applications and, in this paper, we focus on the authentication and self-authentication of e-documents (letters and certificates, for example) that are communicated over the Internet and are thereby vulnerable to attack (e.g. modification, editing, counterfeiting etc.). In addition to document authentication, the approach considered provides a way of propagating disinformation and a solution to scenarios that require ‘plausible deniability’

Security analysis of NIST-LWC contest finalists

Dissertação de mestrado integrado em Informatics EngineeringTraditional cryptographic standards are designed with a desktop and server environment in mind, so, with the relatively recent proliferation of small, resource constrained devices in the Internet of Things, sensor networks, embedded systems, and more, there has been a call for lightweight cryptographic standards with security, performance and resource requirements tailored for the highly-constrained environments these devices find themselves in. In 2015 the National Institute of Standards and Technology began a Standardization Process in order to select one or more Lightweight Cryptographic algorithms. Out of the original 57 submissions ten finalists remain, with ASCON and Romulus being among the most scrutinized out of them. In this dissertation I will introduce some concepts required for easy understanding of the body of work, do an up-to-date revision on the current situation on the standardization process from a security and performance standpoint, a description of ASCON and Romulus, and new best known analysis, and a comparison of the two, with their advantages, drawbacks, and unique traits.Os padrões criptográficos tradicionais foram elaborados com um ambiente de computador e servidor em mente. Com a proliferação de dispositivos de pequenas dimensões tanto na Internet of Things, redes de sensores e sistemas embutidos, apareceu uma necessidade para se definir padrões para algoritmos de criptografia leve, com prioridades de segurança, performance e gasto de recursos equilibrados para os ambientes altamente limitados em que estes dispositivos operam. Em 2015 o National Institute of Standards and Technology lançou um processo de estandardização com o objectivo de escolher um ou mais algoritmos de criptografia leve. Das cinquenta e sete candidaturas originais sobram apenas dez finalistas, sendo ASCON e Romulus dois desses finalistas mais examinados. Nesta dissertação irei introduzir alguns conceitos necessários para uma fácil compreensão do corpo deste trabalho, assim como uma revisão atualizada da situação atual do processo de estandardização de um ponto de vista tanto de segurança como de performance, uma descrição do ASCON e do Romulus assim como as suas melhores análises recentes e uma comparação entre os dois, frisando as suas vantagens, desvantagens e aspectos únicos

Software and hardware implementation of the RSA public key cipher

Cryptographic systems and their use in communications are presented. The advantages obtained by the use of a public key cipher and the importance of this in a commercial environment are stressed. Two two main public key ciphers are considered. The RSA public key cipher is introduced and various methods for implementing this cipher on a standard, nondedicated, 8 bit microprocessor are investigated. The performance of the different algorithms are evaluated and compared. Various ways of increasing the performance are considered. The limitations imposed by the performance on the practical use of the cipher are discussed. The importance of the key to the security of the cipher is assessed. Different forms of attack are mentioned and a procedure for generating keys, which minimise the probability of a sucessful attack is presented. This procedure is implemented on a minicomputer. Use of the method on personal computers or microprocessors is examined. Methods for performing multiplication in hardware, with particular emphasis on the use of these methods in modular multiplication, are detailed. An algorithm for performing part of the encryption function in hardware and the hardware necessary for it is described. Different methods for implementing the hardware are discussed and one is choosen. A description of the hardware unit is given. The design and development of an application specific integrated circuit (ASIC) to perform key elements of the encryption function is described. The various stages of the design process are detailed. The results expected from this device and its integration into the overall encryption scheme are presented

Enhancing Electromagnetic Side-Channel Analysis in an Operational Environment

Side-channel attacks exploit the unintentional emissions from cryptographic devices to determine the secret encryption key. This research identifies methods to make attacks demonstrated in an academic environment more operationally relevant. Algebraic cryptanalysis is used to reconcile redundant information extracted from side-channel attacks on the AES key schedule. A novel thresholding technique is used to select key byte guesses for a satisfiability solver resulting in a 97.5% success rate despite failing for 100% of attacks using standard methods. Two techniques are developed to compensate for differences in emissions from training and test devices dramatically improving the effectiveness of cross device template attacks. Mean and variance normalization improves same part number attack success rates from 65.1% to 100%, and increases the number of locations an attack can be performed by 226%. When normalization is combined with a novel technique to identify and filter signals in collected traces not related to the encryption operation, the number of traces required to perform a successful attack is reduced by 85.8% on average. Finally, software-defined radios are shown to be an effective low-cost method for collecting side-channel emissions in real-time, eliminating the need to modify or profile the target encryption device to gain precise timing information

Enigma 2000: An Authenticated Encryption Algorithm For Human-to-Human Communication

Enigma 2000 (E2K) is a cipher that updates the World War II-era Enigma Machine for the twenty-first century. Like the original Enigma, E2K is intended to be computed by an offline device; this prevents side channel attacks and eavesdropping by malware. Unlike the original Enigma, E2K uses modern cryptographic algorithms; this provides secure encryption. E2K is intended for encrypted communication between humans only, and therefore it encrypts and decrypts plaintexts and ciphertexts consisting only of the English letters A through Z plus a few other characters. E2K uses a nonce in addition to the secret key, and requires that different messages use unique nonces. E2K performs authenticated encryption, and optional header data can be included in the authentication. This paper defines the E2K encryption and decryption algorithms, analyzes E2K’s security, and describes an encryption appliance based on the Raspberry Pi computer for doing E2K encryptions and decryptions offline

Dynamic block encryption with self-authenticating key exchange

One of the greatest challenges facing cryptographers is the mechanism used for key exchange. When secret data is transmitted, the chances are that there may be an attacker who will try to intercept and decrypt the message. Having done so, he/she might just gain advantage over the information obtained, or attempt to tamper with the message, and thus, misguiding the recipient. Both cases are equally fatal and may cause great harm as a consequence. In cryptography, there are two commonly used methods of exchanging secret keys between parties. In the first method, symmetric cryptography, the key is sent in advance, over some secure channel, which only the intended recipient can read. The second method of key sharing is by using a public key exchange method, where each party has a private and public key, a public key is shared and a private key is kept locally. In both cases, keys are exchanged between two parties. In this thesis, we propose a method whereby the risk of exchanging keys is minimised. The key is embedded in the encrypted text using a process that we call `chirp coding', and recovered by the recipient using a process that is based on correlation. The `chirp coding parameters' are exchanged between users by employing a USB flash memory retained by each user. If the keys are compromised they are still not usable because an attacker can only have access to part of the key. Alternatively, the software can be configured to operate in a one time parameter mode, in this mode, the parameters are agreed upon in advance. There is no parameter exchange during file transmission, except, of course, the key embedded in ciphertext. The thesis also introduces a method of encryption which utilises dynamic blocks, where the block size is different for each block. Prime numbers are used to drive two random number generators: a Linear Congruential Generator (LCG) which takes in the seed and initialises the system and a Blum-Blum Shum (BBS) generator which is used to generate random streams to encrypt messages, images or video clips for example. In each case, the key created is text dependent and therefore will change as each message is sent. The scheme presented in this research is composed of five basic modules. The first module is the key generation module, where the key to be generated is message dependent. The second module, encryption module, performs data encryption. The third module, key exchange module, embeds the key into the encrypted text. Once this is done, the message is transmitted and the recipient uses the key extraction module to retrieve the key and finally the decryption module is executed to decrypt the message and authenticate it. In addition, the message may be compressed before encryption and decompressed by the recipient after decryption using standard compression tools