|
|
Post-quantum cryptography on constrained devices
Matula, Lukáš ; Dzurenda, Petr (referee) ; Malina, Lukáš (advisor)
In recent years, there has been a lot of technological development, which among other things, brings the designs and implementation of quantum computing. Using Shor’s algorithm for quantum computing, it is highly likely that the mathematical problems, which underlie the cryptographic systems, will be computed in polynomial time. Therefore, it is necessary to pay attention to the development of post-quantum cryptography, which is able to secure systems against quantum attacks. This work includes the summary and the comparison of different types of post-quantum cryptography, followed by measuring and analysing its levels of difficulty in order to implement them into limited devices, such as smart cards. The measured values on the PC are used to determine the most suitable implementation on the circuit card and then the verification method itself is implemented on it.
|
|
|
Post-quantum cryptography on constrained devices
Matula, Lukáš ; Dzurenda, Petr (referee) ; Malina, Lukáš (advisor)
In recent years, there has been a lot of technological development, which among other things, brings the designs and implementation of quantum computing. Using Shor’s algorithm for quantum computing, it is highly likely that the mathematical problems, which underlie the cryptographic systems, will be computed in polynomial time. Therefore, it is necessary to pay attention to the development of post-quantum cryptography, which is able to secure systems against quantum attacks. This work includes the summary and the comparison of different types of post-quantum cryptography, followed by measuring and analysing its levels of difficulty in order to implement them into limited devices, such as smart cards. The measured values on the PC are used to determine the most suitable implementation on the circuit card and then the verification method itself is implemented on it.
|
|
|
Quantum computing in many-body physics
Brandejs, Jan ; Cejnar, Pavel (advisor) ; Knapp, František (referee)
Název práce: Kvantové výpočty v mnohočásticové fyzice Autor: Jan Brandejs Katedra: Ústav částicové a jaderné fyziky Vedoucí bakalářské práce: prof. RNDr. Pavel Cejnar, Dr., DSc., Ústav částicové a jaderné fyziky Abstrakt: Při simulaci mnohočásticových kvantových systém· obvykle dochází k exponenciální explozi výpočetní složitosti. Kvantové počítače umožňují ten- to problém principiálně vyřešit. Díky práci R. Feynmanna je známo, že axiomy teorie složitosti vychází z fyzikálních zákon·. Situace se změní, zavedeme-li do výpočetního procesu mimo klasické fyziky i kvantovou teorii. Ukazuje se, že pro efektivní simulaci kvantového systému je vhodné použít jiný, lépe kontrolovatelný kvantový systém. Realizace výpočtu s využitím q-bit· a kvantového paralelismu pak ve vybraných případech vede k zásadní redukci složitosti. Kvantové počítače potenciálně umožňují realizaci výpočt· a simulací, které jsou s klasickými počíta- či prakticky neproveditelné. Zejména na poli kvantové chemie vyvstává možnost přímočaré aplikace. Tato práce je zaměřena na použití kvantových počítač· pro mnohočásticové problémy a obsahuje analýzu složitosti kvantové simulace atomo- vých jader. Klíčová slova: kvantový počítač, kvantová simulace, mnohočásticová fyzika
|
|
|
Zjednodušení kvantových obvodů pro modulární umocňování
Fišer, Petr ; Ivánek, Jiří (advisor) ; Nentvich, Libor (referee)
This thesis is based on top of the previous thesis "Security of modern encryption protocols" where we introduced a new paradigm for constructing quantum circuits. We have built circuits for modular arithmetic (addition, multiplication and exponentiation) in order to break El-Gamal asymmetric cryptosystem. Current thesis reviews all proposed circuits and discusses possibilities of their further optimization in goal of lowering the number of used qbits at least by an order of magnitude. It also shows that this is not possible due to existence of COPY gates which make the design inherently unoptimizable. Getting rid of COPY gates is, however, not possible without substantial rewrite of the whole paradigm. The overall estimate of number of qbits used in circuits thus remains O(log(m)log^2(N)) where m is a processed number and N is a modulus. The thesis also proposes optimization of the modular multiplication circuit that, if issues with COPY gates are resolved, allows us to lower the number of used qbits by about O(log(m)) at the price of a longer execution time.
|
|
|
Quantum computers and their impact on public-key cryptography
Lushnikova, Marina ; Ivánek, Jiří (advisor) ; Palovský, Radomír (referee)
The aim of this thesis is to study quantum computers and their impact on public-key cryptography. Crucial part of the work is dedicated to theoretical basis and definitions necessary for understanding the basic principles of quantum computers. The further chapters describe Shor's algorithm, explain the part of integer factoring problem in the security of current public key cryptographic algorithms, and show how to break the most widely used assymetric algorithm RSA by means of effective factoring. Last chapter provides comparison of classical factoring algorithms with Shors algorithm, mentions cryptography resistant to quantum computer attacks and discusses the current state of development in the field of qunatum computing. The conclusion summarizes both potential and real impact of quantum computers on public-key cryptography.
|
guest ::
