I was interested in researching the underlying factors that drove resiliency in regional U.S. hotel markets. I did this by conducting an empirical analysis of twenty nine different markets post September 11 and investigating general, leisure and business variables. I concluded that leisure variables were the underlying drivers of resiliency in regional U.S. hotel markets. I then conducted an event study to try to apply my findings to stock market prices of publicly traded hotel companies. Although it was a challenge to differentiate between companies that depended more on leisure versus business customers due to their asset diversification, I categorized each company into one of the two subsets. If my findings held, I would assume that that the cumulative abnormal returns for the companies that relied on business customers would be more negative than the companies who relied on leisure customers. However, this was not the case, so the findings that leisure variables drive market resiliency were not a good predictor of stock market reaction.

This thesis focuses on video watermarking robust against geometric attacks and video compressions. In addition to the requirements for an image watermarking algorithm, a digital video watermarking algorithm has to be robust against advanced video compressions, frame loss, frame swapping, aspect ratio change, frame rate change, intra- and inter-frame filtering, etc. Video compression, especially, the most efficient compression standard, H.264, and geometric attacks, such as rotation and cropping, frame aspect ratio change, and translation, are considered the most challenging attacks for video watermarking algorithms. In this thesis, we first review typical watermarking algorithms robust against geometric attacks and video compressions, and point out their advantages and disadvantages. Then, we propose our robust video watermarking algorithms against Rotation, Scaling and Translation (RST) attacks and MPEG-2 compression based on the logpolar mapping and the phase-only filtering method. Rotation or scaling transformation in the spatial domain results in vertical or horizontal shift in the log-polar mapping (LPM) of the magnitude of the Fourier spectrum of the target frame. Translation has no effect in this domain. This method is very robust to RST attacks and MPEG-2 compression. We also demonstrate that this method can be used as a RST parameters detector to work with other watermarking algorithms to improve their robustness to RST attacks. Furthermore, we propose a new video watermarking algorithm based on the 1D DFT (one-dimensional Discrete Fourier Transform) and 1D projection. This algorithm enhances the robustness to video compression and is able to resist the most advanced video compression, H.264. The 1D DFT for a video sequence along the temporal domain generates an ideal domain, in which the spatial information is still kept and the temporal information is obtained. With detailed analysis and calculation, we choose the frames with highest temporal frequencies to embed the fence-shaped watermark pattern in the Radon transform domain of the selected frames. The performance of the proposed algorithm is evaluated by video compression standards MPEG-2 and H.264; geometric attacks such as rotation, translation, and aspect-ratio changes; and other video processing. The most important advantages of this video watermarking algorithm are its simplicity, practicality and robustness.

For some applications, elliptic curve cryptography (ECC) is an attractive choice because it achieves the same level of security with a much smaller key size in comparison with other schemes such as those that are based on integer factorization or discrete logarithm. Unfortunately, cryptosystems including those based on elliptic curves have been subject to attacks. For example, fault-based attacks have been shown to be a real threat in today’s cryptographic implementations. In this thesis, we consider fault-based attacks and countermeasures for ECC. We propose a new fault-based attack against the Montgomery ladder elliptic curve scalar multiplication (ECSM) algorithm. For security reasons, especially to provide resistance against fault-based attacks, it is very important to verify the correctness of computations in ECC applications. We deal with protections to fault attacks against ECSM at two levels: module and algorithm. For protections at the module level, where the underlying scalar multiplication algorithm is not changed, a number of schemes and hardware structures are presented based on re-computation or parallel computation. It is shown that these structures can be used for detecting errors with a very high probability during the computation of ECSM. For protections at the algorithm level, we use the concepts of point verification (PV) and coherency check (CC). We investigate the error detection coverage of PV and CC for the Montgomery ladder ECSM algorithm. Additionally, we propose two algorithms based on the double-and-add-always method that are resistant to the safe error (SE) attack. We demonstrate that one of these algorithms also resists the sign change fault (SCF) attack.

For some applications, elliptic curve cryptography (ECC) is an attractive choice because it achieves the same level of security with a much smaller key size in comparison with other schemes such as those that are based on integer factorization or discrete logarithm. Unfortunately, cryptosystems including those based on elliptic curves have been subject to attacks. For example, fault-based attacks have been shown to be a real threat in today’s cryptographic implementations. In this thesis, we consider fault-based attacks and countermeasures for ECC. We propose a new fault-based attack against the Montgomery ladder elliptic curve scalar multiplication (ECSM) algorithm. For security reasons, especially to provide resistance against fault-based attacks, it is very important to verify the correctness of computations in ECC applications. We deal with protections to fault attacks against ECSM at two levels: module and algorithm. For protections at the module level, where the underlying scalar multiplication algorithm is not changed, a number of schemes and hardware structures are presented based on re-computation or parallel computation. It is shown that these structures can be used for detecting errors with a very high probability during the computation of ECSM. For protections at the algorithm level, we use the concepts of point verification (PV) and coherency check (CC). We investigate the error detection coverage of PV and CC for the Montgomery ladder ECSM algorithm. Additionally, we propose two algorithms based on the double-and-add-always method that are resistant to the safe error (SE) attack. We demonstrate that one of these algorithms also resists the sign change fault (SCF) attack.

My dissertation focuses on a set of Anglo-American novels that deal with the events of 9/11. Identifying thematic and stylistic differences in the fiction on this topic, I distinguish between novels that represent directly the jolts of trauma in the wake of the attacks, and novels that, while still holding the events as an underlying operative force in the narrative, do not openly represent them but envision their long-term aftermath. The first group of novels comprises Lynne Sharon Schwartz’s The Writing on the Wall (2005), Don DeLillo’s Falling Man (2007) and Jonathan Safran Foer’s Extremely Loud and Incredibly Close (2005). The second one includes Lorrie Moore’s A Gate at the Stairs (2009), John Updike’s Terrorist (2006) and Joseph O’Neill’s Netherland (2008). Drawing on concepts from trauma theory, particularly by Cathy Caruth and Dominick LaCapra, and combining them with the ethical philosophies of Levinas and Heidegger, I argue that the constructions of 9/11 in Anglo-American fiction are essentially twofold: authors who narrate 9/11 as a tragic human loss in the city of New York turn it into an occasion for an ethical dialogue with the reader and potentially with the “Other,” whereas authors who address 9/11 as a recent sociopolitical event transform it into a goad toward a bitter cultural indictment of the US middle-class, whose ingrained inertia, patriotism and self-righteousness have been either magnified or twisted by the attacks. Considering processes of meaning-making, annihilation, ideological reduction and apathy that arose from 9/11 and its versions, I have identified what could be called, adapting Peter Elbow’s expression from pedagogical studies, the “forked” rhetoric of media and politics, a rhetorical mode in which both discourses are essentially closed, non-hermeneutic, and rooted in the same rationale: exploiting 9/11 for consensus. On the contrary, in what I call the New-Yorkization of 9/11, I highlighted how the situatedness of the public discourses that New Yorkers constructed to tell their own tragedy rescues the Ur-Phaenomenon of 9/11 from the epistemological commodification that intellectual, mediatic and political interpretations forced on it. Furthermore, pointing to the speciousness of arguments that deem 9/11 literature sentimental and unimaginative, I claim that the traumatic literature on the attacks constitutes an example of ethical practice, since it originates from witnesses of the catastrophe, it represents communal solidarity, and it places a crucial demand on the reader as an empathic listener and ethical agent. Ethical counternarratives oppose the ideological simplification of the 9/11 attacks and develop instead a complex counter-rhetoric of emotions and inclusiveness that we could read as a particular instantiation of an ethics of the self and “Other.” As much as the 9/11 “ethical” novels suggest that “survivability” in times of trauma depends on “relationality” (J. Butler), the “cultural” ones unveil the insensitivity and superficiality of the actual US society far away from the site of trauma. The binary framework I use implies that, outside of New York City, 9/11 is narrated neither traumatically (in terms of literary form), nor as trauma (in terms of textual fact). Consequently, on the basis of a spatial criterion and in parallel to the ethical novels, I have identified a category of “cultural” fiction that tackles the events of 9/11 at a distance, spatially and conceptually. In essence, 9/11 brings neither shock, nor promise of regeneration to these peripheral settings, except for Joseph O’Neill’s Netherland, a story in which we are returned to a post-9/11 New York where different ethnic subjects can re-negotiate creatively their identities. The cultural novels are ultimately pervaded by a mode of tragic irony that is unthinkable for the ethical novels and that is used in these texts to convey the inanity and hubris of a politically uneducated and naïve America – one that has difficulties to point Afghanistan on a map, or to transcend dualistic schemes of value that embody precisely Bush’s Manichaeism. The potential for cultural pluralism, solidarity and historical memory set up by the New York stories does not ramify into the America that is far away from the neuralgic epicenter of historical trauma. This proves that the traumatizing effects and the related ethical calls engendered by 9/11 remain confined to the New York literature on the topic.

Syfte: Syftet med studien är att belysa hur 11 september-attackerna gestaltades i svensk och brittisk morgonpress en vecka efter händelserna. Tyngdpunkten i undersökningen ligger på jämförelsen mellan tidningarnas gestaltningar av händelserna. Frågeställningar: Hur gestaltas nyheten veckan efter katastrofen? Vilka likheter och skillnader finns mellan tidningarnas gestaltningar? Hur ser förhållandet mellan text respektive bilder/nyhetsgrafik ut i de båda tidningarna? Teori: Studiens teoretiska ramverk är gestaltningsteorin och främst Robert Entmans modeller. Gestaltningsteorin handlar om mediernas inflytande över hur människor upplever och uppfattar den verklighet vi lever i. Då studien är en jämförelse mellan svensk och brittisk dagspress kontextualiseras studien genom en skildring av situationen för dagspressen i respektive land. Metod: Uppsatsen har undersökt gestaltningar i medieinnehåll genom att använda kvantitativ innehållsanalys som metod för insamling av empiriskt material. Materialet utgörs av samtliga artiklar om 11 september-attackerna i Dagens Nyheter och The Guardian från 2001-09-12 och en vecka framåt. Analysen är utförd på 191 artiklar. Resultat: Förekomst av konfliktgestaltning, human interest-gestaltning, ansvarsgestaltning och ekonomisk konsekvensgestaltning identifierades i båda tidningar. De förstnämnda accentueras mer i The Guardian medan ekonomisk konsekvensgestaltning förekom i högre utsträckning i DN. Indikationer på förekomst av moralgestaltning fanns i The Guardian men kunde inte bekräftas. Även andra faktorer som påverkar nyhetsgestaltningen identifierades. Undersökningen visade även att texten och bilderna i anslutning i viss mån förutsätter varandra då de stärker varandras gestaltningar. Utrymmet för själva artiklarna varierade stort mellan tidningarna. The Guardian hade fler utrymmeskrävande artiklar såväl som bilder. / Purpose: The study aims to shed light on how the September 11 attacks were framed in Swedish and British newspapers one week after the events occured. The main focus of the study is to compare the newspapers' framing of the events. Issues: In what ways are the news portrayed during the week after the events occured? What similarities and differences are there between the newspapers' framings of the events? How much space does text and images/news graphics occupy in the two papers? Theory: The study's theoretical framework is framing theory, mainly Robert Entmans ideas about the different depictions of media. Framing theory is all about how the media influence the way people experience and perceive the reality we live in. Since the study aims to compare Swedish and British newspapers, a contextualisation is performed through a depiction of the situation of the press in Sweden and the UK. Method: The essay has examined the framings in media content by using quantitative content analysis as a method for collecting empirical data. The material consists of all items on the September 11 attacks in Dagens Nyheter and The Guardian, from the date 2001-09-12 and a week ahead. The analysis was conducted on 191 articles. Results: Conflict frame, human interest frame, responsibility frame and economic consequences frame were identified in both newspapers. The former were accentuated in The Guardian. Economic consequences frame was more common in DN. Indications of morality framing were found in the Guardian, but could not be confirmed. In addition, factors having effect on news framing were identified. The study also revealed that text and images presuppose each other while reinforcing each other's frames. The space for the articles themselves varied considerably between the papers. The Guardian contained more space demanding articles as well as images.

Synchronous stream ciphers constitute an important class of symmetric ciphers. After the call of the eSTREAM project in 2004, 34 stream ciphers with different design approaches were proposed. In this thesis, we aim to provide a general framework to analyze stream ciphers statistically. Firstly, we consider stream ciphers as pseudo random number generators and study the quality of their output. We propose three randomness tests based on one dimensional random walks. Moreover, we theoretically and experimentally analyze the relations of various randomness tests. We focus on the ideas of algebraic, time memory tradeoff (TMTO) and correlation attacks and propose a number of chosen IV distinguishers. We experimentally observe statistical weaknesses in some of the stream ciphers that are believed to be secure.

NTRU is a public key cryptosystem, which was first introduced in 1996. It is a ring-based cryptosystem and its security relies on the complexity of a well-known lattice problem, i.e. shortest vector problem (SVP). There is no efficient algorithm known to solve SVP exactly in arbitrary high dimensional lattices. However, approximate solutions to SVP can be found by lattice reduction algorithms. LLL is the first polynomial time algorithm that finds reasonable short vectors of a lattice. The best known attacks on the NTRU cryptosystem are lattice attacks. In these attacks, the lattice constructed by the public key of the system is used to find the private key. The target vector, which includes private key of the system is one of the short vectors of the NTRU lattice. In this thesis, we study NTRU cryptosystem and lattice attacks on NTRU. Also, we applied an attack to a small dimensional NTRU lattice.

One of the most important cryptographic primitives is the concept of block ciphers which yields confidentiality for data transmission in communication. Therefore, to be sure that confidentiality is provided, it is necessary to analyse the security of block ciphers by investigating their resistance to existing attacks. For this reason, related-key attacks gain much popularity in recent years and have been applied to many block ciphers with weak key schedules. In this work, our main motivation is to cover types of related-key attacks on block ciphers and exemplify them. For years, cryptanalysts have been investigating the security of the block cipher XTEA and proposed several attacks on the cipher. First in FSE&#039 / 02, Moon et al. presented a 14-round impossible differential attack on XTEA. Then in ICISC&#039 / 03, Hong et al. proposed a 15-round differential attack and a 23-round truncated differential attack on XTEA. In FSE&#039 / 04, Ko et al. proposed a 27-round related-key truncated differential attack on XTEA. Afterwards, in Vietcrypt&#039 / 06, Lee et al. proposed a 34-round related-key rectangle attack on XTEA. Finally in 2008, Lu improved this attack to a related-key rectangle attack on 36-round XTEA which is the best attack on XTEA in terms of the number of attacked rounds. In this thesis, we also analyse differential properties of both structure and key schedule of XTEA block cipher and introduce our 25-round related-key impossible differential distinguisher for XTEA.

In recent years, the development of mobile networks is thriving or flourishing from 2G GSM, 2.5G GPRS, 3G UMTS to All-IP 4G, which integrates all heterogeneous networks and becomes mature and popular nowadays. Using mobile devices for voice transferring and multimedia sharing is also a part of our life. Mobile networks provide us an efficient way to exchange messages easily. However, these messages often contain critical personal data or private information. Transferring these messages freely in mobile network is dangerous since they can be eavesdropped easily by malicious mobile users for some illegal purposes, such as committing a crime. Hence, to avoid the exposure of the transmitted messages, robust security mechanisms are required. In this thesis, we will propose a one-round mutual authentication protocol which is computation and communication efficient and secure such that the privacy of mobile users¡¦ identities and the confidentiality of their transmitted data are guaranteed. In computation complexity, the protocol only employs symmetric encryption and hash-mac functions. Due to the possession of forward secrecy, the past encrypted messages are secure, even under the exposure of long-term keys. Furthermore, our scheme achieves the goal of user privacy and location privacy by changing TMSI in every session. Therefore, the third party cannot link two different sessions by eavesdropping the communication. Finally, our scheme also can prevent false base attacks which make use of a powerful base station to redirect mobile users¡¦ messages to a fake base station to obtain certain advantages.