Design and Analysis of Security Schemes for Low-cost RFID Systems

With the remarkable progress in microelectronics and low-power semiconductor technologies, Radio Frequency IDentification technology (RFID) has moved from obscurity into mainstream applications, which essentially provides an indispensable foundation to realize ubiquitous computing and machine perception. However, the catching and exclusive characteristics of RFID systems introduce growing security and privacy concerns. To address these issues are particularly challenging for low-cost RFID systems, where tags are extremely constrained in resources, power and cost. The primary reasons are: (1) the security requirements of low-cost RFID systems are even more rigorous due to large operation range and mass deployment; and (2) the passive tags' modest capabilities and the necessity to keep their prices low present a novel problem that goes beyond the well-studied problems of traditional cryptography. This thesis presents our research results on the design and the analysis of security schemes for low-cost RFID systems. Motivated by the recent attention on exploiting physical layer resources in the design of security schemes, we investigate how to solve the eavesdropping, modification and one particular type of relay attacks toward the tag-to-reader communication in passive RFID systems without requiring lightweight ciphers. To this end, we propose a novel physical layer scheme, called Backscatter modulation- and Uncoordinated frequency hopping-assisted Physical Layer Enhancement (BUPLE). The idea behind it is to use the amplitude of the carrier to transmit messages as normal, while to utilize its periodically varied frequency to hide the transmission from the eavesdropper/relayer and to exploit a random sequence modulated to the carrier's phase to defeat malicious modifications. We further improve its eavesdropping resistance through the coding in the physical layer, since BUPLE ensures that the tag-to-eavesdropper channel is strictly noisier than the tag-to-reader channel. Three practical Wiretap Channel Codes (WCCs) for passive tags are then proposed: two of them are constructed from linear error correcting codes, and the other one is constructed from a resilient vector Boolean function. The security and usability of BUPLE in conjunction with WCCs are further confirmed by our proof-of-concept implementation and testing. Eavesdropping the communication between a legitimate reader and a victim tag to obtain raw data is a basic tool for the adversary. However, given the fundamentality of eavesdropping attacks, there are limited prior work investigating its intension and extension for passive RFID systems. To this end, we firstly identified a brand-new attack, working at physical layer, against backscattered RFID communications, called unidirectional active eavesdropping, which defeats the customary impression that eavesdropping is a ``passive" attack. To launch this attack, the adversary transmits an un-modulated carrier (called blank carrier) at a certain frequency while a valid reader and a tag interacts at another frequency channel. Once the tag modulates the amplitude of reader's signal, it causes fluctuations on the blank carrier as well. By carefully examining the amplitude of the backscattered versions of the blank carrier and the reader's carrier, the adversary could intercept the ongoing reader-tag communication with either significantly lower bit error rate or from a significantly greater distance away. Our concept is demonstrated and empirically analyzed towards a popular low-cost RFID system, i.e., EPC Gen2. Although active eavesdropping in general is not trivial to be prohibited, for a particular type of active eavesdropper, namely a greedy proactive eavesdropper, we propose a simple countermeasure without introducing extra cost to current RFID systems. The needs of cryptographic primitives on constraint devices keep increasing with the growing pervasiveness of these devices. One recent design of the lightweight block cipher is Hummingbird-2. We study its cryptographic strength under a novel technique we developed, called Differential Sequence Attack (DSA), and present the first cryptanalytic result on this cipher. In particular, our full attack can be divided into two phases: preparation phase and key recovery phase. During the key recovery phase, we exploit the fact that the differential sequence for the last round of Hummingbird-2 can be retrieved by querying the full cipher, due to which, the search space of the secret key can be significantly reduced. Thus, by attacking the encryption (decryption resp.) of Hummingbird-2, our algorithm recovers 36-bit (another 28-bit resp.) out of 128-bit key with $2^{68}$ ($2^{60}$ resp.) time complexity if particular differential conditions of the internal states and of the keys at one round can be imposed. Additionally, the rest 64-bit of the key can be exhaustively searched and the overall time complexity is dominated by $2^{68}$. During the preparation phase, by investing $2^{81}$ effort in time, the adversary is able to create the differential conditions required in the key recovery phase with at least 0.5 probability. As an additional effort, we examine the cryptanalytic strength of another lightweight candidate known as A2U2, which is the most lightweight cryptographic primitive proposed so far for low-cost tags. Our chosen-plaintext-attack fully breaks this cipher by recovering its secret key with only querying the encryption twice on the victim tag and solving 32 sparse systems of linear equations (where each system has 56 unknowns and around 28 unknowns can be directly obtained without computation) in the worst case, which takes around 0.16 second on a Thinkpad T410 laptop

A study of Robert Schumann's Impromptus, Op. 5 : its sources and a critical analysis of its revisions

Like a number of early compositions by Schumann, the Impromptus, Op. 5, was considerably revised in later years. It is one of only several works whose early and later versions are both included in the complete edition of his works published by Breitkopf and Hartel. Brahms, co-editor with Clara Schumann of this edition, was probably responsible for the inclusion of the two separate versions, recognizing the distinct virtues of the first, possibly even its superiority to the second. [TRUNCATED

Levinas, Messianism and parody

Levinas has come to be seen as one of the principle representatives in contemporary thought of a certain philosophically articulated concept of 'messianism'. On the one hand, the appeal by philosophy to messianism is conceived by many as a 'turn' within postmodern thought broadly conceived towards a theology and ethics. On the other hand, there is the closely related consensus that Levinas‘ messianism is an expression of a certain 'correlation' between 'philosophy' and 'Judaism', a correlation in which Judaism becomes the suppressed voice of conscience of the latter. We revisit some of the consensuses upon which these related understandings are based. Firstly, we consider whether the heterogeneity of Levinas‘ different articulations of the messianic dimension should be emphasized, a heterogeneity which defies simple classification. Secondly, we consider whether Levinas‘ thought can properly be called messianic as such: we emphasize the functional character of messianism in Levinas, and how messianism is structurally re-ordered according to the function it takes on. We explore namely the manner in which messianic discourse in Levinas is implicated in the construction of a certain humanism, and how it is called upon to negotiate the obstacles which such a construction faces. Re-ordered according to this regime, we consider whether what unites the various expressions of messianism in Levinas is not the articulation of a discourse which progressively realizes its non-eschatological status. We frame this thesis in terms of what we call the 'parody' of messianism, a notion we derive from Nietzsche. This complicates any notion of a 'turn' within postmodernism; and yet it can be shown to be an intensification of a certain tendency at work already within normative Judaism

Irony and ambiguity in Beethoven's string quartets

This thesis explores the view that many of the difficulties and apparent eccentricities of Beethoven's Late Quartets (particularly Op. 130, 132, 133 and 135) may be understood in terms of irony, in the sense that it appears in the philosophical and aesthetic writings of the early German Romantics. A chain of influence is demonstrated between Beethoven and Friedrich Schlegel's philosophy of Romantic irony, through significant inter -personal relationships as well as through Beethoven's exposure to Schlegel's written works. This connection provides a firm hermeneutic basis for considering the composer's work in terms of irony.The A minor Quartet Op. 132 is given as an example of Beethoven's Romantic irony, and considered in terms of the constitutive elements of Schlegel's Romantic irony - Paradox, Parabasis and Self -consciousness. However, this thesis also demonstrates that the irony within the Late Quartets goes beyond the confines of Romantic irony. The paradoxical structures of the Cavatina and Grosse Fuge are considered as examples of "general" or "existential" irony -a form closely related to Schlegelian irony. Moreover, the replacement finale of the Op. 130 quartet is shown to constitute a striking instance of satire: a bitter ironic comment upon the musical conservatism of Beethoven's critics.This thesis therefore explores the philosophical background and the nature of irony itself, relating all of its forms to one underlying structure and to one fundamental process. This process - "objectification" - is derived from the work of Mikhail Bakhtin, and forms the theoretical basis for the structural approach of the analyses of irony within the thesis. The thesis also considers the relationship between irony and related phenomena such as wit and humour. It suggests that the differences between these concepts correspond to those between Beethoven's Romantic irony and the wit and humour of his predecessors.Finally, the relationship between irony and ambiguity is also considered. Ambiguity is frequently elided with irony within theoretical writing on irony; indeed the terms "irony" and "ambiguity" are often used synonymously. Since ambiguity is a significant element of the harmonic and formal practices within the Quartets this elision is important: if ambiguity and irony are elided then each instance of ambiguity may be considered ironic - a reductio ad absurdum. This work distinguishes ambiguity and irony as separate phenomena, approaching this division through the semiotic concepts of "immanence" and "manifestation ". I argue that ambiguity occurs as a particular effect of the immanent level of discourse, whilst irony occurs entirely within the manifest level. In addition to this difference in function, different structures are demonstrated for these phenomena. This distinction is applied to the third movement of the Op. 130 Quartet, which is considered as a confrontation of Classical aesthetics with the equivocal and ambiguou

The Cultural Contradictions of Cryptography

This dissertation examines the origins of political and scientific commitments that currently frame cryptography, the study of secret codes, arguing that these commitments took shape over the course of the twentieth century. Looking back to the nineteenth century, cryptography was rarely practiced systematically, let alone scientifically, nor was it the contentious political subject it has become in the digital age. Beginning with the rise of computational cryptography in the first half of the twentieth century, this history identifies a quarter-century gap beginning in the late 1940s, when cryptography research was classified and tightly controlled in the US. Observing the reemergence of open research in cryptography in the early 1970s, a course of events that was directly opposed by many members of the US intelligence community, a wave of political scandals unrelated to cryptography during the Nixon years also made the secrecy surrounding cryptography appear untenable, weakening the official capacity to enforce this classification. Today, the subject of cryptography remains highly political and adversarial, with many proponents gripped by the conviction that widespread access to strong cryptography is necessary for a free society in the digital age, while opponents contend that strong cryptography in fact presents a danger to society and the rule of law. I argue that cryptography would not have become invested with these deep political commitments if it had not been suppressed in research and the media during the postwar years. The greater the force exerted to dissuade writers and scientists from studying cryptography, the more the subject became wrapped in an aura of civil disobedience and public need. These positive political investments in cryptography have since become widely accepted among many civil libertarians, transparency activists, journalists, and computer scientists who treat cryptography as an essential instrument for maintaining a free and open society in the digital age. Likewise, even as opponents of widespread access to strong cryptography have conceded considerable ground in recent decades, their opposition is grounded in many of the same principles that defined their stance during cryptography’s public reemergence in the 1970s. Studying this critical historical moment reveals not only the origins of cryptography’s current politics, but also the political origins of modern cryptography

Representations of Mind

After defending the view that we can read off the metaphysics of the things we talk about from the form and interpretation of the language we use to talk about things, I develop and defend an account of the form and interpretation of propositional attitude reports (and some closely related constructions) and then read off the metaphysics of propositional attitudes. Views on the metaphysics of speech acts, propositions, and propositionally articulated thoughts also fall out of the account. The result is a tightly knit sets of views which I think together solve a number of outstanding philosophical problems. Given the centrality and importance of the attitudes and reports thereof to our making sense of ourselves and others as minded beings, not to mention their centrality to many domains of philosophy, the hope is that this makes a contribution to our self-understanding. It should also be a contribution to cognitive science

"Constructive destruction" as response to suffering. Prolegomena to a "concept" of salutary disaster on the crossroad of philosophy, philosophy of religion and literature

The following thesis develops the idea of 'constructive destruction' in close readings of selected texts by Soren Kierkegaard, Theodor W. Adorno, Franz Kafka, Gershom Scholem and Philip Roth. 1. The focus on the study is on 'suffering' and 'constructive destruction' in the 'modern' period, which means that 'suffering' is being understood primarily as internal (respectively)- existential suffering. 2. Kierkegaard's "The Sickness unto Death" is a typical example of this very kind of suffering. Kierkegaard's theoretical treatise of suffering in this writing is problematic, though I argue that a close inspection of his literary strategy of pseudonymity allows for a more positive evaluation of his contribution. 3. The reading of Adorno's reading of Kierkegaard introduces the idea of constructive destruction, for Adorno has attempted to wring the positive out of the collapse of Kierkegaard's 'system'. 4. Kafka's aphorisms are the source of the term 'constructive destruction'. They were written in a time of severe crisis, and they develop this idea particularly in reflections about the im/possibility of dying. Kafka's work was related to philosophical and religious ideas of constructive destruction by Maurice Blanchot and, more extensively, by Gershom Scholem: Scholem sees Kafka's work as a (in his times) contemporary form of heretical Kabbalah, for which Sabbatianisms is a prime example; Sabbatianism, again, enacts constructive destruction. 5. Philip Roth's novel "Sabbath's Theatre" may or may not play with the name of founder of this Jewish sect. Either way it can be read as a contemporary reflection of the logic of constructive destruction as response to suffering. 6. My selection of texts and my method of reading are unconventional but not random. The method is located at the crossroad of philosophy of religion and literature and inspired by what I call differential analogy. The result of my reading is not a recipe for the overcoming of suffering; rather, I provide models for meaningful responses to suffering that can inspire our perceptions of the conflicts that we may (quite likely) face in one way or another