The security of a cryptosystem in most cases relies on the key being kept secret. Quantum key distribution (QKD) enables two authenticated parties without other prior information to share a perfectly secure key. However, repeatedly using the same key to encrypt many different messages is not perfectly secure. A trivial method to obtain a secret key is to use QKD to reestablish a new key for each message. In this thesis, we study an efficient method to update the keys. We call this method quantum key evolution (QKE). The QKE provides a new secret key in each round of the protocol. Therefore, a new secret key is established for next round of protocol execution. We study two problems to present secure schemes applying the QKE. First, we present a new quantum message transmission protocol, to transmit long secret message using less quantum bits than the methods of incorporating QKD with one-time pad, as well as some quantum secure direct communication protocols. Second, we present three-party authenticated quantum key distribution protocols which enable two communicating parties to authenticate the other's identity and establish a session key between them via a trusted center. For the security of our protocols, we give formal standard reduction proofs to the security of our protocols. We show that the security of our protocol is equivalent to the security of BB84 protocol which has been proved to be unconditionally secure. Therefore, our protocols are unconditionally secure.

In recent times the usage of smart phones has significantly increased. Businesses are transforming to make more out of smart phones. As a consequence, there is an increasing demand to have more and more mobile applications. Among other areas, mobile applications are also being used to make financial transactions. Applications used for financial transactions need to be more reliable and have end-to-end security. To implement security we heavily depend on cryptography and the heart of cryptography is the keys which are used in cryptographic processes (encryption/decryption). Therefore, it is essential not only to protect, but also to properly manage these keys, so that a robust and secure system can be achieved. This research work provides a complete implementation of symmetric key management for mobile phone applications with a focus on financial data using a key hierarchy approach. We have developed a key management system which allows smart phones to download the cryptographic key hierarchy. This key hierarchy is used to encrypt and decrypt financial data, such as PIN and other transaction information. Using this application (key management system), we can achieve an end-to-end security between client (mobile phones) and payment server (banking server). This research work presents implementation of key management system for Android OS only.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes the system-level architecture and design concept of a communications security (COMSEC) equipment intended for space-based low data rate (< 1 Mbps) command and telemetry applications. The COMSEC Unit is a stand-alone piece of equipment which provides decryption of uplink command and control information and encryption of downlink telemetry data. The system-level architecture is described followed by an overview of the digital design concepts and a discussion of applications. Finally, although specifically targeted for narrowband command and telemetry applications, this design approach is flexible enough to accommodate other algorithms of choice as well as operate in higher data rate applications.

published_or_final_version / Computer Science / Master / Master of Philosophy

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Traditional manufacturing industry have developed a linear production path that involves resource extraction, energy usage, emissions released to air and water, and waste produced at volumes and rates that places increasing burden on the natural environment. These traditional manufacturing organizations have mostly viewed environmental activities separately from their core business operations. Today, organizations are shifting their manufacturing approach. There is a significant potential to reduce the energy use, emissions released, resource consumption and wastes produced through sustainable initiatives. Using environmental key performance indicators (KPIs) is one emerging sustainability initiative. Environmental KPIs depict the vast quantity of environmental data of a firm in a comprehensive and concise manner, applying mostly to set absolute material and energy data in relation to other variables in order to increase the informational value of quantitative data. In this thesis work, literature review and empirical study was carried out to find out the significant factors and the major challenges during the development and implementation of environmental key performance indicators (KPIs). A case study in four Swedish manufacturing companies was carried out to collect primary data which was later compared with literature review. The thesis work also highlights the management system used to implement environmental KPIs.

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In this thesis we study the notion of circular security for bit-encryption schemes. Informally speaking, a bit-encryption scheme is circular secure if it remains secure even if the key of the system is used to encrypt its own individual bits. This notion (or slight extensions thereof) has foundational applications, most notably in the context of fully-homomorphic encryption and amplification techniques for key dependent- message security. We explore the notion of circular security from three different perspectives, stemming from (1) assumptions sufficient to realize this notion, (2) minimal black-box assumptions on which this notion can be based and (c) applications of this notion when combined with other properties. Our main results are as follows: We give a construction of circular-secure public-key bit encryption based on any public-key encryption scheme that satisfies two special properties. We show that our constructed scheme besides circular security also offers two forms of key-leakage resilience. Our construction unifies two existing specific constructions of circular-secure schemes in the literature and also gives rise to the first construction based on homomorphic hash proof systems. We show that seed-circular-secure public-key bit-encryption schemes cannot be based on semantically-secure public-key encryption schemes in a fully-blackbox way. A scheme is seed-circular-secure if it allows for the bits of the seed (used to generate the public/secret keys) to be securely encrypted under the corresponding public key. We then extend this result to rule out a large and non-trivial class of constructions for circular security that we call key-isolating constructions. We give generic constructions of several fundamental cryptographic primitives based on a public-key bit-encryption scheme that combines circular security with a structural property called reproducibility. The main primitives that we build include families of trapdoor functions with strong security properties (i.e., one-wayness under correlated inputs), adaptive-chosen-ciphertext (CCA2) secure encryption schemes and deterministic encryption schemes. / Graduate / 0984

Distributional data and taxonomic keys art presented for thirty-four species of Plecoptera known to occur in Oklahoma. Ten species are new records for the state. Descriptions are provided for two species new to science, Zealeuctra cherokee and Isoperla brevis, and for the previously unknown male of Strophopteryx cucullata Frison and female of Helopicus nalatus (Frison).