|
|
Multi-factor authentication using smart devices to access a cloud service
Huška, Luděk ; Malina, Lukáš (referee) ; Dzurenda, Petr (advisor)
This thesis addresses the issue of current multi-factor authentication methods for modern ICT systems. With increasing demands for security and digitalization, data protection is crucial. The thesis provides an overview of current technologies and solutions in the area of multi-factor authentication and explores their integration into a system for accessing the Nextcloud cloud service using an Android mobile application. The theoretical part deals with authorization, authentication, access control and cryptography basics. The practical part includes the development of an Android application and the implementation of the server part using the ECDSA protocol. The result is a functional login process and an app for Nextcloud that enhances data security and provides users with a more convenient and secure way to log in.
|
|
|
Efficient Digital Signature Schemes
Varga, Ondrej ; Sobotka, Jiří (referee) ; Malina, Lukáš (advisor)
Digital signatures, which take the properties of classical signatures, are used to secure the actual content of documents, which can be modified during transmission over an insecure channel. The problems of security and protection of communicating participants are solved by cryptographic techniques. Identity verification, message integrity, credibility, the ownership of documents, and the secure transmission of information over an unsecured channel, are all dealt with in secure communications - Public Key Infrastructure, which uses digital signatures. Nowadays digital signatures are often used to secure data in communication over an unsecured channel. The aim of the following master’s thesis is to familiarize readers with the necessary technological aspects of digital signatures, as well as their advantages and disadvantages. By the time digital signatures are being used they will have to be improved and modified to be secure against more sophisticated attacks. In this paper, proposals of new efficient digital signature schemes and their comparison with current ones are described. Also are examined their implications for computationally weak devices, or deployment in low speed channel transmission systems. After an explanation of cryptography and a description of its basic subjects, digital signatures are introduced. The first chapter describes the possible formatting and architecture of the digital signature. The second part of this master’s thesis is about current digital signature schemes and their properties. Chapter 3 describes some proposals of new efficient digital signature schemes and their comparison to those currently in use. In the practical part, the implementations (in the environment .NET in C#) of two effective digital signature schemes as part of a client-server application are presented and described (Chapter 4). In the last chapter the comparison and analysis of the implemented signature schemes are provided.
|
|
|
Web User Interface for Pass Password Manager
Chroust, Michal ; Burget, Radek (referee) ; Rychlý, Marek (advisor)
The goal of the thesis is implementation of password manager with support of version control trough git and encryption using OpenPGP.js library. Work addresses suitable structure of storing passwords in memory, Promise library usage, conversion to and from Base64, passwords security, HTTPS requests and git service usage. It also focuses on tools and technologies used troughout application development. Application allows it's use both on server and browser.
|
|
|
Cryptography based on semirings
Mach, Martin ; Korbelář, Miroslav (advisor) ; El Bashir, Robert (referee)
Cryptography based on semirings can be one of the possible approaches for the post-quantum cryptography in the public-key schemes. In our work, we are interested in only one concrete semiring - tropical algebra. We are examining one concrete scheme for the key-agreement protocol - tropical Stickel's protocol. Although there was introduced an attack on it, we have implemented this attack and more importantly, stated its complexity. Further, we propose other variants of Stickel's protocol and we are investigating their potential for practical usage. During the process, we came across the theory of tropical matrix powers, thus we want to make an overview of it due to the use in cryptography based on matrices over the tropical algebra semiring. 1
|
|
|
Web User Interface for Pass Password Manager
Chroust, Michal ; Burget, Radek (referee) ; Rychlý, Marek (advisor)
The goal of the thesis is implementation of password manager with support of version control trough git and encryption using OpenPGP.js library. Work addresses suitable structure of storing passwords in memory, Promise library usage, conversion to and from Base64, passwords security, HTTPS requests and git service usage. It also focuses on tools and technologies used troughout application development. Application allows it's use both on server and browser.
|
|
|
NTRU cryptosystem and its modifications
Poláková, Kristýna ; Příhoda, Pavel (advisor) ; Korbelář, Miroslav (referee)
The theses firstly introduces the basics of lattice problems. Then it focuses on various aspects of the cryptosystem NTRU which is based on the mentioned problems. The system is then compared with the most common encryption methods used nowadays. Its supposed quantum resistence is mentioned briefly. Subsequently the author tries to minimize the system's disadvantages by various cryptosystem modifications. Powered by TCPDF (www.tcpdf.org)
|
|
|
Diffie and Hellman are exchanging matrices over group rings
Linkeová, Romana ; Příhoda, Pavel (advisor) ; El Bashir, Robert (referee)
Title: Diffie and Hellman are exchanging matrices over group rings Author: Romana Linkeová Department: Department of Algebra Supervisor: Mgr. Pavel Příhoda, Ph.D., Department of Algebra Abstract: The Diffie-Hellman key exchange protocol is not suitable for devices with limited computational power while computing over group Z∗ p (where p is at least a 300-digit number). This fact led to the research of other algebraic structures, which may help in reducing the computational and storage cost of the protocol. D. Kahrobaei et al. posted in 2013 a proposal for working over a structure of small matrices and claimed that this modification will not affect the security of the protocol. We will attempt to attack this modification of the Diffie- Hellman protocol with the help of the theory of symmetric group representations. Firstly, we mention the basics of the theory of representations together with both the classical and the modified Diffie-Hellman protocol. Next, we elaborate the attack step by step and complement some of the steps with examples. Then, we probed security of the modified protocol against the baby-step giant-step attack. Keywords: public key cryptography, symmetric group representations, Diffie-Hellman protocol 1
|
|
|
Efficient Digital Signature Schemes
Varga, Ondrej ; Sobotka, Jiří (referee) ; Malina, Lukáš (advisor)
Digital signatures, which take the properties of classical signatures, are used to secure the actual content of documents, which can be modified during transmission over an insecure channel. The problems of security and protection of communicating participants are solved by cryptographic techniques. Identity verification, message integrity, credibility, the ownership of documents, and the secure transmission of information over an unsecured channel, are all dealt with in secure communications - Public Key Infrastructure, which uses digital signatures. Nowadays digital signatures are often used to secure data in communication over an unsecured channel. The aim of the following master’s thesis is to familiarize readers with the necessary technological aspects of digital signatures, as well as their advantages and disadvantages. By the time digital signatures are being used they will have to be improved and modified to be secure against more sophisticated attacks. In this paper, proposals of new efficient digital signature schemes and their comparison with current ones are described. Also are examined their implications for computationally weak devices, or deployment in low speed channel transmission systems. After an explanation of cryptography and a description of its basic subjects, digital signatures are introduced. The first chapter describes the possible formatting and architecture of the digital signature. The second part of this master’s thesis is about current digital signature schemes and their properties. Chapter 3 describes some proposals of new efficient digital signature schemes and their comparison to those currently in use. In the practical part, the implementations (in the environment .NET in C#) of two effective digital signature schemes as part of a client-server application are presented and described (Chapter 4). In the last chapter the comparison and analysis of the implemented signature schemes are provided.
|
guest ::
