Národní úložiště šedé literatury Nalezeno 16 záznamů.  1 - 10další  přejít na záznam: Hledání trvalo 0.00 vteřin. 
Deepfake Detection Framework
Bernard, Jan ; Perešíni, Martin (oponent) ; Malinka, Kamil (vedoucí práce)
Deepfake creation has improved a lot in recent times and hence is a dreaded menace to society. Deepfake detection methods have also responded with development, but there are still not enough good tools available to the general public. This work focuses on creating a deepfake detection framework that will be easily extended by other detection methods in the future, yet simple and accessible to the general public.
Secure and Efficient State Preservation in Ethereum-Based Smart Contract Platforms
Eršek, Martin ; Perešíni, Martin (oponent) ; Homoliak, Ivan (vedoucí práce)
This thesis presents a solution to mitigate state-related challenges in Ethereum. By analyzing Ethereum internals and relevant literature, the identified problems are addressed. A proof-of-concept implementation showcases promising results, such as up to a 33% reduction in membership proof size and nearly a 50% decrease in mean transaction execution time compared to existing solutions. Furthermore, the proposed solution enables effective parallel processing with over a 97% chance of non-conflicting execution for 8 random native transfer transactions. Future work involves implementing a parallel execution client and integrating the solution into production, advancing Ethereum's state management capabilities.
Analysis of the Move Programming Language for Blockchain Platforms
Šmehýl, Adam ; Homoliak, Ivan (oponent) ; Perešíni, Martin (vedoucí práce)
This thesis studies the Move programming language, focusing on its usability for developing applications (smart contracts or programs) on blockchain platforms. Two key aspects are considered: first, a comparison of programming models using Move to widely used models of EVM-compatible platforms like Ethereum and the popular Solana blockchain; and second, the implementation of the same program in Solidity on Ethereum, Rust on Solana, and Move on Aptos. Criteria for comparison include deployment and execution costs, processing speed, code readability, and overall development experience. A detailed analysis of Move's unique features, such as resource management, the use of generics, and other security enhancements in programming, is conducted. The results demonstrate Move's potential for extensive use in the blockchain field, with its strong emphasis on secure coding and resource management contributing to the growing interest within the blockchain community.
Incentive Strategies for Transaction-Fee Regime of Proof-of-Work Blockchains
Budinský, Rastislav ; Perešíni, Martin (oponent) ; Homoliak, Ivan (vedoucí práce)
In this thesis, we review the undercutting attacks in the transaction-fee-based regime of Proof-of-Work (PoW) blockchains with the longest chain fork-choice rule. Next, we focus on the problem of fluctuations in mining revenue and the mining gap -- i.e., a situation, in which the immediate reward from transaction fees does not cover miners' expenditures. To mitigate these issues, we propose a solution that splits transaction fees from a mined block into two parts -- (1) an instant reward for the miner of a block and (2) a deposit sent to one or more Fee-Redistribution Contracts ($\mathcal{FRC}$s) that are part of the consensus protocol. At the same time, these redistribution contracts reward the miner of a block with a certain fraction of the accumulated funds of the incoming fees over a predefined time. This setting enables us to achieve several interesting properties that are beneficial for the incentive stability and security of the protocol. With our solution, the fraction of \textsc{Default-Compliant} miners who strictly do not execute undercutting attack is lowered from the state-of-the-art result of 66\% to 30\%.
Security and Performance Testbed for Simulation of Proof-of-Stake Protocols
Hud, Jakub ; Perešíni, Martin (oponent) ; Homoliak, Ivan (vedoucí práce)
This thesis deals with testing the security and performance of PoS-based protocols. Comparison of ProPos, Algorand, Hedera, Ouroboros and Tezos is presented on theoretical level in terms of performance, attack vulnerabilities and attacks mitigation. This thesis includes a simulation framework for testing Algorand, ProPos and Hedera protocols. The simulation framework is created using Omnet++ 5.4.1. Focus of the simulation experiments is on the performance of the selected protocols. Based on the results of the experiments a few improvements are discussed.
Fast Synchronization of New Nodes in the Fantom Opera Platform
Mlejnek, Matěj ; Homoliak, Ivan (oponent) ; Perešíni, Martin (vedoucí práce)
The goal of this master thesis is to research current ways of fast synchronization of new nodes in blockchain networks, considering different consenses. Then to compare these solutions, design feasible solution and then implement the new fast synchronisation for blockchain network Fantom Opera. The solution is based on an idea where new node in network doesn't connect to P2P network, but directly connects to one of the nodes and downloads just the necessary data to be synchronized with rest of network as fast as possible.
Software and Hardware Based Fault Injection Attacks against the CPU and MCU
Lörinc, Marek ; Hanáček, Petr (oponent) ; Perešíni, Martin (vedoucí práce)
The thesis deals with attacks that cause faults in CPU and MCU calculations. A short voltage change in CPU or MCU is used to trigger the error. The theoretical part of the thesis deals with the description of how to cause and exploit these errors. This section also describes the most well-known protection against hardware attacks, which is a trusted execution environment (TEE). Inject a fault to TEE is the primary target of fault attacks. The practical part deals with the replication of PlunderVolt and VoltPillager attacks on Intel processors with an activated TEE SGX. Several experiments were performed to trigger faults in RSA and AES encryption within the SGX enclave. To obtain the encryption key from these errors, known analysis methods were used. The practical part also deals with the replication of the attack on ARM microcontrollers with an active TEE TrustZone-M.
Mobile Cryptocurrency Wallet Based on zk-SNARKs and Smart Contracts
Slávka, Samuel ; Perešíni, Martin (oponent) ; Homoliak, Ivan (vedoucí práce)
The goal of this thesis is to propose and implement a framework for cryptocurrency wallets. The framework optimizes light client storage and bandwidth requirements in mobile devices. We propose a side-chain mechanism that validates blockchain header chains and creates zero-knowledge proofs. Furthermore, the framework stores the results of proof verification inside an Ethereum Smart contract. The Smart contract supports fork handling and storing header chains for multiple different blockchains. Light mobile clients using this framework can update their local header chain from checkpoints created by the proof verifications results stored in the Smart Contract. This thesis includes an implementation of a mobile wallet using this framework for synchronization with multiple blockchains.
Utilization of Blockchain Technology in the Area of Mechanical Engineering
Džupa, Oliver ; Perešíni, Martin (oponent) ; Tamaškovič, Marek (vedoucí práce)
This bachelor’s thesis focuses on utilization of blockchain technology in the area of mechanical engineering. The first part is devoted to a full understanding of blockchain and smart contracts. The second part summarizes the use cases for both mechanical engineering and non-mechanical engineering fields and identifies features presented by blockchain. The third part is focused on case studies of conceptual utilization of blockchains in mechanical engineering and comparison with centralized solutions.
IoT Gateways Network Communication Analysis
Zbořil, Jan ; Perešíni, Martin (oponent) ; Malinka, Kamil (vedoucí práce)
Modern IoT gateways are mainly developed by private companies behind closed doors. This results in a closed ecosystem, where only a tiny amount of information about traffic is available to the public. Therefore, to gain knowledge regarding the operation and communication of such gateways, it is necessary to examine and analyse network traffic flowing to and from such gateways. This thesis's primary goal is to capture and process network traffic data of multiple commercially available gateways intended for home use, analyse their communication behaviour, compare the results to other studies carried out in this area, and discuss possible attacks on used gateways, based on gathered data. Communication data were obtained by deploying a controlled environment and analysed using Zeek, together with Wireshark software. Collected communication data can be further used by researchers in the areas of networking or security.

Národní úložiště šedé literatury : Nalezeno 16 záznamů.   1 - 10další  přejít na záznam:
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