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Garbled Circuit (GC) is the main practical 2PC technique, yet despite great interest in its performance, GC notoriously resists improvement. Essentially, we only know how to evaluate GC functions gate-by-gate using encrypted truth tables; given input labels, the GC evaluator decrypts the corresponding output label. Interactive protocols enjoy more sophisticated techniques. For example, we can expose to a party a (masked) private value. The party can then perform useful local computation and feed the resulting cleartext value back into the MPC. Such techniques are not known to work for GC. We show that it is, in fact, possible to improve GC efficiency, while keeping its round complexity, by exposing masked private values to the evaluator. %without introducing rounds of communication. Our improvements use garbled one-hot encodings of values. By using this encoding we improve a number of interesting functions, e.g., matrix multiplication, integer multiplication, field element multiplication, field inverses and AES S-Boxes, integer exponents, and more. We systematize our approach by providing a framework for designing such GC modules. Our constructions are concretely efficient. E.g., we improve binary matrix multiplication inside GC by more than 6x in terms of communication and by more than 4x in terms of WAN wall-clock time. Our improvement circumvents an important GC lower bound and may open GC to further improvement.

Relational properties describe relationships that hold over multiple executions of one or more programs, such as functional equivalence. Conventional approaches for automatically verifying such properties typically rely on syntax-based, heuristic strategies for finding synchronization points among the input programs. These synchronization points are then annotated with appropriate relational invariants to complete the proof. However, when suboptimal synchronization points are chosen the required invariants can be complicated or even inexpressible in the target theory. In this work, we propose a novel approach to verifying relational properties. This approach searches for synchronization points and synthesizes relational invariants simultaneously. Specifically, the approach uses synthesized invariants as a guide for finding proper synchronization points that lead to a complete proof. We implemented our approach as a tool named PEQUOD, which targets Java Virtual Machine (JVM) bytecode. We evaluated PEQUOD by using it to solve verification challenges drawn from the from the research literature and by verifying properties of student-submitted solutions to online challenge problems. The results show that PEQUOD solve verification problems that cannot be addressed by current techniques., In Proceedings HCVS/PERR 2019, arXiv:1907.03523

We build a complete and efficient ZK toolchain that handles proof statements encoded as arbitrary ANSI C programs.Zero-Knowledge (ZK) proofs are foundational in cryptography. Recent ZK research has focused intensely on non-interactive proofs of small statements, useful in blockchain scenarios. We instead target large statements that are useful, e.g., in proving properties of programs.Recent work (Heath and Kolesnikov, CCS 2020 [HK20a]) designed an efficient proof-of-concept ZK machine (ZKM). Their machine executes arbitrary programs over a minimal instruction set, authenticating in ZK the program execution. In this work, we significantly extend this research thrust, both in terms of efficiency and generality. Our contributions include:• A rich and performance-oriented architecture for representing arbitrary ZK proofs as programs.• A complete compiler toolchain providing full support for ANSI C95 programs. We ran off-the-shelf buggy versions of the Linux programs sed and gzip, proving in ZK that each program has a bug. To our knowledge, this is the first ZK system capable of executing standard Linux programs.• Improved ZK oblivious RAM (ORAM). [HK20a] introduced an efficient ZK-specific ORAM BubbleRAM that consumes O(log2 n) communication per access. We extend BubbleRAM with multi-level caching, decreasing communication to O(log n) per access. This introduces the possibility of a cache miss, which we handle cheaply. Our experiments show that cache misses are rare; in isolation, i.e., ignoring other processor costs, BubbleCache improves communication over BubbleRAM by more than 8×. Using BubbleCache improves our processor’s total communication (including costs of cache misses) by ≈ 25-30%.• Numerous low-level optimizations, resulting in a CPU that is both more expressive and ≈ 5.5× faster than [HK20a]’s.• Attention to user experience. Our engineer-facing ZK instrumentation and extensions are minimal and easy to use.Put together, our system is efficient and general, and can run many standard Linux programs. The resultant machine runs at up to 11KHz on a 1Gbps LAN and supports MBs of RAM.

Secure two party computation (2PC) of arbitrary programs can be efficiently achieved using garbled circuits (GC). Until recently, it was widely believed that a GC proportional to the entire program, including parts of the program that are entirely discarded due to conditional branching, must be transmitted over a network. Recent work shows that this belief is false, and that communication proportional only to the longest program execution path suffices (Heath and Kolesnikov, CRYPTO 20, [HK20a]). Although this recent work reduces needed communication, it increases computation. For a conditional with b branches, the players use \(O(b^2)\) computation (traditional GC uses only O(b)).

Katz et al., CCS 2018 (KKW) is a popular and efficient MPC-in-the-head non-interactive ZKP (NIZK) scheme, which is the technical core of the post-quantum signature scheme Picnic, currently considered for standardization by NIST. The KKW approach simultaneously is concretely efficient, even on commodity hardware, and does not rely on trusted setup. Importantly, the approach scales linearly in the circuit size with low constants with respect to proof generation time, proof verification time, proof size, and RAM consumption. However, KKW works with Boolean circuits only and hence incurs significant cost for circuits that include arithmetic operations.

Zero-Knowledge (ZK) proofs (ZKP) are foundational in cryptography. Most recent ZK research focuses on non-interactive proofs (NIZK) of small statements, useful in blockchain scenarios. Another line, and our focus, instead targets proofs of large statements that are useful, e.g., in proving properties of programs in ZK. We specify a zero-knowledge processor that executes arbitrary programs written in a simple instruction set, and proves in ZK the correctness of the execution. Such an approach is well-suited for constructing ZK proofs of large statements as it efficiently supports complex programming constructs, such as loops and RAM access. Critically, we propose several novel ZK improvements that make our approach concretely efficient: (1) an efficient arithmetic representation with conversions to/from Boolean, (2) an efficient read-only memory that uses $2log n$ OTs per access, and (3) an efficient read-write memory, ourram, which uses $\frac1 2 log^2 n$ OTs per access. ourram beats linear scan for RAM of size $>3$ elements! Prior ZK systems used generic ORAM costing orders of magnitude more. We cast our system as a garbling scheme that can be plugged into the ZK protocol of [Jawurek et al, CCS'13]. Put together, our system is concretely efficient: for a processor instantiated with $512$KB of main memory, each processor cycle costs $24$KB of communication. We implemented our approach in \textttC++. On a 1Gbps LAN our implementation realizes a $2.1$KHz processor.

Zero-knowledge (ZK) proofs (ZKP) have received wide attention, focusing on non-interactivity, short proof size, and fast verification time. We focus on the fastest total proof time, in particular for large Boolean circuits. Under this metric, Garbled Circuit (GC)-based ZKP (Jawurek et al., [JKO], CCS 2013) remained the state-of-the-art technique due to the low-constant linear scaling of computing the garbling.

The widespread environmental distribution of pharmaceuticals and personal care products (PPCPs) is well-recognized, and the number of recent studies reflects the continuing interest and high level of research activity on the presence of PPCPs in the environment and food. In order to quantify their low environmental levels, sensitive and selective analytical methodologies are required. Recently, significant effort has gone into determining their concentrations in environmental matrices, with special attention to environment-friendly practices and the development of so-called Green Analytical Chemistry (GAC) methods. GAC is one of the most active areas of research and development in Green Chemistry and represents a real challenge for environmental analytical chemists. Its objective is the introduction of new techniques and methodologies able to minimize the environmental and occupational hazards involved in all stages of chemical analysis, allowing faster and more energy-efficient methods without compromising performance criteria. To accomplish the goal of GAC, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method was introduced. As a result of the inherent advantages of the QuEChERS having “Green Chemistry” characteristics, the method has expanded rapidly to include the extraction of different groups of contaminants from various matrices and emerged as a green alternative to traditional sample preparation steps. This chapter deals with the application of the QuEChERS approach as a “green” sample preparation technique for determining PPCPs residues in environmental and food matrices and highlights major trends in its development. A brief explanation of the analytical technique used is provided together with a discussion of the experimental features of the studies reviewed.

This chapter draws on data collected as part of an Australian Office for Learning and Teaching (OLT) funded project, which explored the use of learning analytics for student retention and success (West et al., 2015). The focus in this chapter is on the critical role of leadership in learning analytics development and the challenges of implementation, especially when it comes to connecting learning analytics to the classroom. The challenges associated with learning analytics implementation are summarised as: 1) complexity of the learning experience; 2) coherence around accountability and role; 3) communication; 4) potential exclusion of teaching staff, and; 5) potential exclusion of the student voice. Strong and effective leadership has the potential to address these challenges to varying degrees. We argue in this chapter that successful development of learning analytics capability and capacity, as well as successful leveraging of such capacity, requires a combination of positional and distributive leadership, and it requires, above all, a coherent and consistent whole-of-institution approach. Most importantly however, applying learning analytics in a meaningful way that is applicable in the classroom requires people with different types of expertise and knowledge to work together, which in turn is significantly aided by strong and effective leadership.

Recursion-free Constrained Horn Clauses (CHCs) are logic-programming problems that can model safety properties of programs with bounded iteration and recursion. In addition, many CHC solvers reduce recursive systems to a series of recursion-free CHC systems that can each be solved efficiently. In this paper, we define a novel class of recursion-free systems, named Clause-Dependence Disjoint (CDD), that generalizes classes defined in previous work. The advantage of this class is that many CDD systems are smaller than systems which express the same constraints but are part of a different class. This advantage in size allows CDD systems to be solved more efficiently than their counterparts in other classes. We implemented a CHC solver named Shara. Shara solves arbitrary CHC systems by reducing the input to a series of CDD systems. Our evaluation indicates that Shara outperforms state-of-the-art implementations in many practical cases., In Proceedings HCVS 2018, arXiv:1809.04554

This paper presents findings from a study of Australian and New Zealand academics (n = 276) that teach tertiary education students. The study aimed to explore participants’ early experiences of learning analytics in a higher education milieu in which data analytics is gaining increasing prominence. Broadly speaking participants were asked about: (1) Their teaching context, (2) Their current student retention activities, (3) Their involvement in, and aspirations for, learning analytics use, (4) Their relationship with their institution around learning analytics. The sampled teaching staff broadly indicated a high level of interest but limited level of substantive involvement in learning analytics projects and capacity building activities. Overall, the intention is to present a critical set of voices that assist in identifying and understanding key issues and draw connections to the broader work being done in the field.

We consider different approaches to the problem of numerically inverting Laplace transforms in finance. In particular, we discuss numerical inversion techniques in the context of Asian option pricing.

Partial Discharge is one of a number of tests defined in IEC61730–2, which specifies properties of photovoltaic modules and components. 3M has used commercially available test equipment from Phenix Technologies to complete a detailed evaluation of noise mitigation techniques for effectively implementing the IEC test standard 60664–1 for Partial Discharge Testing. The PD2U partial discharge detector was designed for quality assurance and quality control tests of high, medium and low voltage insulation in a test laboratory environment. This instrument can be adapted to measure partial discharge inception and extinction voltages per IEC Standard IEC 60664–1 by use of various preamplifier and couplers. The standard set configuration of the PD2U consists of a coupling unit CIL4L, a preamplifier RPA1 and the instrument. The acquisition unit controls the power supply and the Preamplifier unit (RPA1) through a standard coaxial cable which also transmits the partial discharge signal. Compliance with IEC 60664–1 requires background noise levels to remain under 1 pC. Using noise mitigation and noise evaluation diagnostics in a NAVLP certified IEC emissions and immunity compliant testing chamber resulted in continually sustained background noise levels of less than a few hundred fC. The noise mitigation hardware we have evaluated includes noise filters, designated power synthesizers and isolation transformers, and NAVLP certified and FCC approved shielded enclosures. Given our evaluations and insights gained as a result of this study, our 3M laboratory has been able to routinely carry out partial discharge testing for the purpose of advanced materials research and development.

A fundamental result of this chapter is that prices can be generally obtained under the benchmark approach in situations where other approaches are not available. This chapter also clarifies relationships between real world pricing under the benchmark approach and the pricing by other means in the areas of finance and insurance. Furthermore, it presents the Girsanov transformation, the change of numeraire technique and the Feynman-Kac formula, which are all highly relevant to derivative pricing.

Stochastic differential equations provide a powerful mathematical framework for the continuous time modeling of asset prices and general financial markets. We consider both scalar and vector stochastic differential equations which allow us to model feedback effects in the market. Explicit solutions will be given in certain cases. Furthermore, questions related to the existence and uniqueness of solutions will be discussed. We also mention stochastic differential equations with jumps which allow us to model event driven uncertainty.

In this chapter the fundamental concept of a stochastic process is introduced. We show how stochastic processes can be applied in the context of asset price modeling. The notions of processes with independent increments, stationary processes and Markov processes are explained. Essentially, stochastic processes provide the mathematical framework that allows us to model financial quantities as families of random variables that evolve over time.

In the previous chapters we have prepared mathematical tools that allow us to model in continuous time the dynamics of financial securities, for instance, stocks. Now, we shall study prices of derived financial securities. A derivative security, for instance an option, is a financial instrument whose value is dependent upon the values of an underlying more fundamental security. In this chapter we give an introduction into derivatives, in particular, European options. For simplicity, we focus our discussion on options under the BS model. Furthermore, we introduce at the end of the chapter important results on squared Bessel processes because these will be crucial for the understanding of the following chapters.

This note compares the performance of a queuing system in which customers can enter service only at multiples of the service time to the ordinary counterpart for both G/D/1 and M/D/1 systems. We show that the two modes of operation differ by at most one customer at any point in time. We give motivation for the use of a limited entry queuing system as a model for use in material handling analysis.

We consider the problem of determining rates for a situation in which services are purchased in bulk but have to be paid for by a large number of small users. The desired rates must be “fair” and they must cover all costs. The problem is formulated as a non-atomic game and solved by using the value of the game. In addition to the general problem, we present a detailed actual case, together with computational methods and results.

Free to read at publisher's site. This paper presents a dialogical tool for the advancement of learning analytics implementation for student retention in Higher Education institutions. The framework was developed as an outcome of a project commissioned and funded by the Australian Government’s Office for Learning and Teaching. The project took a mixed-method approach including a survey at the institutional level (n = 24), a survey of individual teaching staff and other academics with an interest in student retention (n = 353), and a series of interviews (n = 23). Following the collection and analysis of these data an initial version of the framework was developed and presented at a National Forum attended by 148 colleagues from 43 different institutions. Participants at the forum were invited to provide commentary on the usefulness and composition of the framework which was subsequently updated to reflect this feedback. Ultimately, it is envisaged that such a framework might offer institutions an accessible and concise tool to structure and systematize discussion about how learning analytics might be implemented for student retention in their own context. © 2016 Online Learning Consortium. All rights reserved.

Directed motion or ratchet-like behavior in many molecular scale systems is a consequence of diffusion mediated transport. The Brownian motor serves as a paradigm. The Parrondo Paradox is a pair of coin toss games, each of which is fair, or even losing, but become winning with a schedule of playing them in alternation. It has been proposed as a discrete analog of the Brownian motor. We examine the relationship between these two systems. We discover a class of Parrondo games with unusual ratchet-like behavior and for which diffusion plays a fundamentally different role than it does in the Brownian motor. Detailed balance is an important feature in these considerations. The Brownian motor depends on details of the potential landscape in the system but the Parrondo game is decided on the potential difference alone. There are winning Parrondo games whose Brownian motor analogs move in the opposite direction. A general framework is discussed in section 7. The original Parrondo game, here in section 7.2, is completely determined by detailed balance.