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Modern Privacy-Preserving Cryptography Protocols
Hlučková, Pavla ; Dzurenda, Petr (referee) ; Malina, Lukáš (advisor)
This thesis examines the intersection of two modern and growing branches of cryptography, namely privacy enhancing technologies and post-quantum cryptography. It describes selected privacy enhancing schemes (PETs) and families of post-quantum cryptography. In more detail, it focuses on group signatures based on mathematical problems that are difficult or intractable for both conventional and quantum computers. Furthermore, the thesis surveys the state of the art and compares the efficiency of mentioned schemes based on available data. The main part of this thesis is an implementation of a hash-based group signature and its comparison with lattice-based and code-based group signature implementations which were obtained directly from cryptographers active in this field. The post-quantum group signatures are subsequently compared to classic group signature schemes implemented by using the libgroupsig library.
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Post-Quantum Ciphers
Novosadová, Tatiana ; Ricci, Sara (referee) ; Hajný, Jan (advisor)
Národný inštitút pre štandardy a technológie (NIST) zahájil proces na získanie, vyhodnotenie a štandardizáciu jedného alebo viacerých kryptografických algoritmov využívajúcich verejný kľúč prostredníctvom verejnej súťaže. Cieľom tejto dimplomovej práce je naštudovať dostupné postkvantové algoritmy pre ustanovenie kľúča, ktoré boli zverejnené v treťom kole tejto súťaže. Po dôkladnej analýze a porovnaní bol jeden zo študovaných algoritmov implementovaný s využitím knižníc dostupných pre daný algoritmus, následne bol program optimalizovaný a zdokumentovaný.
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Measuring Post-Quantum Cryptography on Mobile Platforms
Ramiš, Karel ; Malina, Lukáš (referee) ; Dobiáš, Patrik (advisor)
This work concerns itself with the issue of post-quantum cryptography, particularly its implementation and performance on mobile devices. As part of the work, a mobile application capable of performing basic steps of post-quantum cryptographic schemes and subsequently measuring selected parameters is created. Furthermore, an own version of the CRYSTALS-Kyber scheme for key encapsulation is developed and evaluated.
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Ensuring Long-term Data Integrity in Cloud Storage
Nohava, Martin ; Člupek, Vlastimil (referee) ; Malina, Lukáš (advisor)
The subject of the thesis is the design and development of a system to ensure the long-term integrity of data from the Nextcloud cloud storage, which manages and stores electronic evidence. In the introductory part, the terms and principles used for securing data integrity are presented, including quantum-resistant digital signature schemes. Subsequently, the architecture of the archiving system and the method of its connection with the Nextcloud cloud storage are proposed. The resulting system consists of two main components, the Archive application, which extends the web interface of the Nextcloud instance, and the archiving system, which ensures the integrity of the archived files themselves. In addition to time stamps, system also uses a quantum-resistant Dilithium signature scheme. At the end of the work, an evaluation of the implemented solution is carried out by measuring the performance of the archiving system, and options for its further development are proposed.
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Modular network communication using post-quantum cryptography
Kopecký, Samuel ; Malina, Lukáš (referee) ; Smékal, David (advisor)
Súčasné kryptografické primitíva, ktoré sú popísané na začiatku tejto práce budú prelomené budúcimi kvantovými počítačmi. Táto práca popisuje proces lámania súčasnej krypografie spolu so základným popisom kvantovej mechaniky, ktorá je kľúčom k funkčným kvantovým počítačom. Taktiež predstavuje dostupné riešenia, ako je postkvantová kryptografia. Konkrétnejšie je predstavená kryptografia založená na kódoch, hašoch mriežkach. Najpodrobnejšie je opísaná kryptografia založená na mriežkach a sú predstavené špecifické NIST štandardizované algoritmy – Kyber a Dilithium. Spolu s teoretickým popisom je poskytnutá implementácia pre obidve algoritmy a porovnanie s existujúcimi implementáciami v programovacom jazyku Go. Praktické využitie týchto algoritmov je realizované modulárnou kvantovo odolnou komunikačnou aplikáciou. Je schopná posielať ľubovoľné dáta cez kvantovo odolný zabezpečený kanál a je dobre prispôsobená univerzálnemu textovému rozhraniu UNIX systmémoch. Viac špecificky, aplikácia je schopná vymieňať súbory medzi dvoma používateľmi a tiež vytvárať terminálové používateľské rozhranie, s ktorým môžu používatelia komunikovať. Protokol, ktorý je zodpovedný za vytvorenie zabezpečeného kanála, je dobre definovaný v posledných kapitolách tejto práce. Modularita aplikácie tiež umožňuje používateľom odstrániť a/alebo pridať akýkoľvek mechanizmus výmeny kľúčov alebo digitálny podpis, ktoré sú zodpovedné za vytvorenie zabezpečeného kanála s veľmi malými zmenami kódu a dobrou integráciou do existujúcich komponentov aplikácie.
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An Implementation of Lattice-based Proof-of-Work on Blockchain
Krivulčík, A. ; Ricci, S.
Cryptocurrencies and blockchain are skyrocketing in recent years. They rely on Proof-of-Work (PoW) mechanisms for generating a new transaction and turn this process into ”work” (i.e., puzzles) where miners are paid for. With the advent of quantum computers, also PoW starts to migrate to post-quantum cryptographic alternatives. To the best of our knowledge, we present the first implementation of a lattice-based PoW based on the Shortest Vector Problem (SVP). By implementing in Python 3 and with the use of the NumPy library, we wrote a software that uses this concept on an artificial blockchain and demonstrates its real-world use. Even if this proposal has drawbacks on GPU optimisation and storage requirements, it shows its potential in use. The experimental results show that by balancing the size and generated range of a given matrix and vector, we can easily manipulate the time required to solve SVP challenge.
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Post Quantum Cryptography on FPGA
Gyõri, A. ; Smékal, D.
This work describes the post-quantum algorithm FrodoKEM, its hardware implementation in VHDL and software simulation of implementation. The issue of postquantum cryptography and the VHDL programming language used to describe the functionality of the hardware was studied. The acquired knowledge was transformed into a functional simulation of all parts of the algorithm. All these parts have already been implemented separately, so that the functionality of every single part can be separately approached. These parts are key generation, encapsulation and decapsulation. After successful simulation. These parts will be synthetised and implemented to FPGA board NEXYS A7.
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Modern Privacy-Preserving Cryptography Protocols
Hlučková, Pavla ; Dzurenda, Petr (referee) ; Malina, Lukáš (advisor)
This thesis examines the intersection of two modern and growing branches of cryptography, namely privacy enhancing technologies and post-quantum cryptography. It describes selected privacy enhancing schemes (PETs) and families of post-quantum cryptography. In more detail, it focuses on group signatures based on mathematical problems that are difficult or intractable for both conventional and quantum computers. Furthermore, the thesis surveys the state of the art and compares the efficiency of mentioned schemes based on available data. The main part of this thesis is an implementation of a hash-based group signature and its comparison with lattice-based and code-based group signature implementations which were obtained directly from cryptographers active in this field. The post-quantum group signatures are subsequently compared to classic group signature schemes implemented by using the libgroupsig library.
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Postquantum cryptography on FPGA
Győri, Adam ; Jedlička, Petr (referee) ; Smékal, David (advisor)
This work describes the post-quantum algorithm FrodoKEM, its hardware implementation in VHDL and software simulation of implementation, subsequent implementation of the implementation on the FPGA process system. The work describes the issue of postquantum cryptography and VHDL programming language used to describe the functionality of hardware. Furthermore, the work deals with the functional implementation and simulation of all parts of the algorithm. Specifically, these are parts, key generation, encapsulation, and decapsulation. Algorithm implementation and simulations were performed in the Vivado software simulation environment, created by Xilinx. Subsequently, the synthesis and implementation was performed and the Intellectual property block was designed, the key part of which covered the functionality of the NEXYS A7 FPGA board was not available. The last part of the work deals with the workflow algorithm for implementation on FPGA board NEXYS A7.
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Goppa codes and their applications
Kotil, Jaroslav ; Drápal, Aleš (advisor) ; Šťovíček, Jan (referee)
Title: Goppa codes and their applications Author: Bc. Jaroslav Kotil Department: Department of algebra Supervisor: prof. RNDr. Aleš Drápal, CSc., DSc. Abstract: In this diploma paper we introduce Goppa codes, describe their para- metres and inclusion in Alternant codes, which are residual Generalized Reed- Solomon codes, and Algebraic-geometry codes. Aftewards we demonstrate deco- ding of Goppa codes and introduce Wild Goppa codes. We also describe post- quantum cryptography member: McEliece cryptosystem for which no effective attacks with quantum computers are known. We outline a usage of this crypto- system with Goppa codes and describe the security of the cryptosystem together with possible attacks of which the most effective ones are based on information- set decoding. Keywords: Goppa codes, Generalized Reed-Solomon codes, Algebraic-geometry codes, Post-quantum cryptography, McEliece cryptosystem 1
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