Actual Instantiation Research Articles

CTET+: A Beyond-Birthday-Bound Secure Tweakable Enciphering Scheme Using a Single Pseudorandom Permutation

In this work, we propose a construction of 2-round tweakable substitutionpermutation networks using a single secret S-box. This construction is based on non-linear permutation layers using independent round keys, and achieves security beyond the birthday bound in the random permutation model. When instantiated with an n-bit block cipher with ωn-bit keys, the resulting tweakable block cipher, dubbed CTET+, can be viewed as a tweakable enciphering scheme that encrypts ωκ-bit messages for any integer ω ≥ 2 using 5n + κ-bit keys and n-bit tweaks, providing 2n/3-bit security.Compared to the 2-round non-linear SPN analyzed in [CDK+18], we both minimize it by requiring a single permutation, and weaken the requirements on the middle linear layer, allowing better performance. As a result, CTET+ becomes the first tweakable enciphering scheme that provides beyond-birthday-bound security using a single permutation, while its efficiency is still comparable to existing schemes including AES-XTS, EME, XCB and TET. Furthermore, we propose a new tweakable enciphering scheme, dubbed AES6-CTET+, which is an actual instantiation of CTET+ using a reduced round AES block cipher as the underlying secret S-box. Extensivecryptanalysis of this algorithm allows us to claim 127 bits of security.Such tweakable enciphering schemes with huge block sizes become desirable in the context of disk encryption, since processing a whole sector as a single block significantly worsens the granularity for attackers when compared to, for example, AES-XTS, which treats every 16-byte block on the disk independently. Besides, as a huge amount of data is being stored and encrypted at rest under many different keys in clouds, beyond-birthday-bound security will most likely become necessary in the short term.

AuCPace: Efficient verifier-based PAKE protocol tailored for the IIoT

Increasingly connectivity becomes integrated in products and devices that previously operated in a stand-alone setting. This observation holds for many consumer applications in the so-called "Internet of Things" (IoT) as well as for corresponding industry applications (IIoT), such as industrial process sensors. Often the only practicable means for authentication of human users is a password. The security of password-based authentication schemes frequently forms the weakest point of the security infrastructure. In this paper we first explain why a tailored protocol designed for the IIoT use case is considered necessary. The differences between IIoT and the conventional Internet use-cases result in largely modified threats and require special procedures for allowing both, convenient and secure use in the highly constrained industrial setting. Specifically the use of a verifier-based password-authenticated key-exchange (V-PAKE) protocol as a hedge against public-key-infrastructure (PKI) failures is considered important. Availability concerns for the case of failures of (part of) the communication infrastructure makes local storage of access credentials mandatory. The larger threat of physical attacks makes it important to use memory-hard password hashing. This paper presents a corresponding tailored protocol, AuCPace, together with a security proof within the Universal Composability (UC) framework considering fully adaptive adversaries. We also introduce a new security notion of partially augmented PAKE that provides specific performance advantages and makes them suitable for a larger set of IIoT applications. We also present an actual instantiation of our protocol, AuCPace25519, and present performance results on ARM Cortex-M0 and Cortex-M4 microcontrollers. Our implementation realizes new speed-records for PAKE and X25519 Diffie-Hellman for the ARM Cortex M4 architecture.

Georgia’s frosts: ethnopolitical conflict as assemblage

This article is a reinterpretation of ‘frozen conflicts’ as assemblages binding together and strategically orienting a variety of components from both human and nonhuman estates at various scales in order to make a move toward ‘unfreezing’ their research. It then demonstrates how this perspective may be employed in the case of the ethnopolitical conflict in Georgia. The resulting analysis points to several important processes that animate the constant pulsation of the conflict field even when arms are calm and contribute to the dynamic and becoming nature of the conflict and its dynamic (re-)assembling. It illuminates how the visibility function of the assemblage operates and endows with meaning the structure of relations in the conflict field. It traces how the bricolage of Georgian social association transformed over time, notably under Saakashvili, and how it has also been a key element of statebuilding practice in the separatist entities. The analysis moreover demonstrates how the actual instantiations of collective violence form but a fraction of that which takes place in the conflict field, from other forms of political and criminal violence to regime change, state (un-)making through processes of contraction or extension of heterogenous, ‘hybrid’ governscapes including some distinctly virtual ones but betraying real political effects. Finally, it expounds how the ethnopolitical conflict assemblage affixes together a variety of agency from human agents to institutions from local to state governments or the international conflict resolution apparatus in addition to the material (nonhuman) actants enrolled in the translation networks populating the conflict field.

Spatio-temporal convolution kernels

Trajectory data of simultaneously moving objects is being recorded in many different domains and applications. However, existing techniques that utilise such data often fail to capture characteristic traits or lack theoretical guarantees. We propose a novel class of spatio-temporal convolution kernels to capture similarities in multi-object scenarios. The abstract kernel is a composition of a temporal and a spatial kernel and its actual instantiations depend on the application at hand. Empirically, we compare our kernels and efficient approximations thereof to baseline techniques for clustering tasks using artificial and real world data from team sports.

The effects of augmented virtual science laboratories on middle school students' understanding of gas properties

The Next Generation Science Standards (NGSS) emphasize authentic scientific practices such as developing models and constructing explanations of phenomena. However, research documents how students struggle to explain observable phenomena with molecular-level behaviors with current classroom experiences. For example, physical laboratory experiences in science enable students to interact with observable scientific phenomena, but students often fail to make connections to underlying molecular-level behaviors. Virtual laboratory experiences and computer-based visualizations enable students to interact with unobservable scientific concepts, but students can have difficulties connecting to actual instantiations of the observed phenomenon. This paper investigates how combining physical and virtual experiences into augmented virtual science laboratories can help students build upon intuitive ideas and develop molecular-level explanations of macroscopic phenomena. Specifically, this study uses the Frame, a sensor-augmented virtual lab that uses sensors as physical inputs to control scientific simulations. Eighth-grade students (N = 45) engaged in a Frame lab focused on the properties of gas. Results demonstrate that students using the Frame lab made progress developing molecular-level explanations of gas behavior and refining alternative and partial ideas into normative ideas about gases. This study offers insights for how augmented virtual labs can be designed to enhance science learning and encourage scientific practices as called for in the NGSS.

Signaling Schemes for Revenue Maximization

Signaling is an important topic in the study of asymmetric information in economic settings. In particular, the transparency of information available to a seller in an auction setting is a question of major interest. We introduce the study of signaling when conducting a second price auction of a probabilistic good whose actual instantiation is known to the auctioneer but not to the bidders. This framework can be used to model impressions selling in display advertising. We establish several results within this framework. First, we study the problem of computing a signaling scheme that maximizes the auctioneer’s revenue in a Bayesian setting. We show that this problem is polynomially solvable for some interesting special cases, but computationally hard in general. Second, we establish a tight bound on the minimum number of signals required to implement an optimal signaling scheme. Finally, we show that at least half of the maximum social welfare can be preserved within such a scheme.

Oscar Wilde et le portrait surréel d’un désir invisible

Oscar Wilde’s only novel, The Picture of Dorian Gray, is an intriguing piece of writing for which the concept of the virtual may usefully serve as a paradigm. Apparently, this novel seems to be just another, albeit brilliant, reinterpretation of the Faustian trade-off between eternal youth and a license to indulge in a potlatch of sinful excesses. Dorian Gray’s beauty is depicted as absolute and it is its absoluteness that both defies description in writing and calls for a picture – a masterpiece of course – the splendour of which may be conveyed only in writing. Art and nature meet only in the absolute and the reader’s imagination does the work of showing something which any actual instantiation would prove inevitably disappointing. This article investigates the various and interconnected statuses given by Wilde to virtual images (paintings and photographs as they exist as hallucinations prompted by the text into the readers’ imagination) and to the metaphysical ideal of physical beauty in mystical overtones and entangled articulations to evil, shame, violence and destiny.

Approaches to Deponency

AbstractThe aim of this article is to give an overview of theoretical approaches to (generalized) deponency, i.e., morpho‐syntactic phenomena in the world's languages that resemble deponent verbs in Latin (where passive morphology accompanies active syntax) in that a ‘wrong form’ is apparently used. The paper has three parts. First, the concept of deponency is introduced. Second, a new taxonomy of approaches is developed that extends Stump's original classification by adding two further groups: (i) form deponency, (ii) property deponency, (iii) spurious morpho‐syntactic deponency, and (iv) spurious morphomic deponency. The discussion yields interesting results concerning preferred choices among (i)–(iv) in the literature (with (i) emerging as surprisingly rare and (iv) as surprisingly widespread), and concerning potential correlations between analysis type and overall grammatical framework (there aren't any). In the third part, I sketch a version of what is arguably a fairly straightforward approach to deponency (even though an actual instantiation so far appears to be outstanding): an optimality‐theoretic analysis that takes the hypothesis that deponency involves ‘wrong forms’ literally.

Einstein on the Beach by Robert Wilson and Philip Glass (review)

Reviewed by: Einstein on the Beach by Robert Wilson and Philip Glass Stephen Bottoms Einstein on the Beach. By Robert Wilson and Philip Glass. Choreographed by Lucinda Childs. Barbican Centre, London. 12 May 2012. “Is that it?” I whispered to my companion at the end of four-and-a-quarter hours of Wilson and Glass’s sensory sumptuousness. There was no disappointment implied in those words, no “what was the big deal?” Einstein on the Beach is still spoken of in legendary terms by those who first witnessed it in 1976, so it might be easy for any actual instantiation of it to fail to live up to heightened expectations. But no, I loved what I had seen in this first-ever UK staging. It was simply that we had been warned that the performance was five hours long, and having mentally braced myself for that time span, this astonishing event felt oddly truncated when it ended “early.” (I had only thirty minutes previously ducked out for my one and only bathroom break, spectators at Einstein being famously permitted to come and go at times of their own choosing.) More importantly, however, since this is a plotless performance that induces in the spectator a sense of perpetual present-ness rather than of temporal progression, any ending is necessarily anticlimactic. As Alain Badiou remarks, with specific reference to Wilson: “the contemplative consistency of pure duration [never] saves theatre from its extended finitude, from its long shortness” (Rhapsody for the Theatre, xiv). The choice of Einstein as iconic subject represents, of course, a decision by the collaborating artists to play with the relativity of time. Fragments of potential narrative appear and recur throughout the performance: a young Einstein on a beach; old Einstein endlessly bowing a violin; an inexorable train journey; a strange court case bisected by a prison cell. The images throb with the potential significance of a vivid dream, but circulate and recur through the various scenes and intersecting “knee plays” without ever offering themselves up to “interpretation.” Certain phrases from Christopher Knowles’s texts acquire a kind of comforting familiarity through their insistent repetition (“it could be very fresh and clean”), while Glass’s lush, maximally minimalist score gradually alters one’s consciousness. My own experience of the piece was that time felt curiously elongated and slowed down through the first thirty to forty minutes, as my habituated urge to seek progression and development was inevitably frustrated. During scene 2 (trial 1) I was fighting to stay awake, a factor that further elongated things (have minutes passed or only seconds since I last nodded out?). But after this point I fell into the flow, and the next three hours or so passed—wide awake—without any particular consciousness of time. Click for larger view View full resolution Helga Davis and Kate Moran in Einstein on the Beach. (Photo: Lucie Jansch.) Admittedly, some elements of the performance appealed to me more than others. I cannot say that I am a particular fan of the twirling Lucinda Childs choreography, but I adored the crisp, quirky, automaton-like performances of Kate Moran and Helga Davis in the twin MC roles. And I was simply in awe of the pop-up choir’s ability to sing up and down number sequences, in perfect unison, at breakneck speed! But that fascination with the live reproduction of music that sounds synthesized or treated (yet is not) led to my one significant frustration with the performance. The musicians were positioned underneath the stage, mostly invisible to the audience except when the choir popped up in a shallow forestage pit area. I found that I wanted to be able to see the score being played, as part of the visual landscape of the piece—a desire that also, perhaps, says something about time. In 1976, with synthesized sound still in its infancy, the fact of the score’s live reproduction was perhaps more of a given than it is today. Glass’s music is composed of analog sounds whose hypnotic repetitiveness anticipates the advent of digital sampling. Today, the ubiquity of looped, digitized music means that, for this viewer at least, there is a curious fascination with...

Synchronous objects with scheduling policies

This paper addresses the problem of designing and implementing complex control systems for real-time embedded software. Typical applications involve different control laws corresponding to different phases or modes , e.g., take-off, full flight and landing in a fly-by-wire control system. On one hand, existing methods such as the combination of Simulink/Stateflow provide powerful but unsafe mechanisms by means of imperative updates of shared variables. On the other hand, synchronous languages and tools such as Esterel or SCADE/Lustre are too restrictive and forbid to fully separate the specification of modes from their actual instantiation with a particular control automaton. In this paper, we introduce a conservative extension of a synchronous data-flow language close to Lustre, in order to be able to define systems with modes in a more modular way, while insuring the absence of data-races. We show that such a system can be viewed as an object where modes are methods acting on a shared memory. The object is associated to a scheduling policy which specifies the ways methods can be called to build a valid synchronous reaction. We show that the verification of the proper use of an object reduces to a type inference problem using row types introduced by Wand, Rémy and Vouillon. We define the semantics of the extended synchronous language and the type system. The proposed extension has been implemented and we illustrate its use through several examples.

The Precautionary Principle and the Regulation of U.S. Food and Drug Safety

This article probes the advisability of regulating U.S. food and drug safety according to the precautionary principle. To do so, a precautionary regulatory regime is formulated on the basis of the beliefs that motivate most proponents of this initiative. That hypothetical regime is critically analyzed on the basis of an actual instantiation of a similarly stylized initiative. It will be argued that the precautionary principle entails regulatory constraints that are apt to violate basis tenets of political legitimacy. The modifications that would change this finding would also change precautionary regulation to the point that it would be indistinguishable from orthodox safety protocols. It is concluded on the basis of its impoverished content that the precautionary principle should not be taken seriously as a formal approach to the regulation of U.S. food and drug safety.