Biblio

Developers often wonder how to implement a certain functionality (e.g., how to parse XML files) using APIs. Obtaining an API usage sequence based on an API-related natural language query is very helpful in this regard. Given a query, existing approaches utilize information retrieval models to search for matching API sequences. These approaches treat queries and APIs as bags-of-words and lack a deep understanding of the semantics of the query. We propose DeepAPI, a deep learning based approach to generate API usage sequences for a given natural language query. Instead of a bag-of-words assumption, it learns the sequence of words in a query and the sequence of associated APIs. DeepAPI adapts a neural language model named RNN Encoder-Decoder. It encodes a word sequence (user query) into a fixed-length context vector, and generates an API sequence based on the context vector. We also augment the RNN Encoder-Decoder by considering the importance of individual APIs. We empirically evaluate our approach with more than 7 million annotated code snippets collected from GitHub. The results show that our approach generates largely accurate API sequences and outperforms the related approaches.

Heterogeneous Chip Multiprocessors have been shown to provide significant performance and energy efficiency gains over homogeneous designs. Recent research has expanded the dimensions of heterogeneity to include diverse Instruction Set Architectures, called Heterogeneous-ISA Chip Multiprocessors. This work leverages such an architecture to realize substantial new security benefits, and in particular, to thwart Return-Oriented Programming. This paper proposes a novel security defense called HIPStR – Heterogeneous-ISA Program State Relocation – that performs dynamic randomization of run-time program state, both within and across ISAs. This technique outperforms the state-of-the-art just-in-time code reuse (JIT-ROP) defense by an average of 15.6%, while simultaneously providing greater security guarantees against classic return-into-libc, ROP, JOP, brute force, JIT-ROP, and several evasive variants.

The Internet of Things (IoT) is a design implementation of embedded system design that connects a variety of devices, sensors, and physical objects to a larger connected network (e.g. the Internet) which requires human-to-human or human-to-computer interaction. While the IoT is expected to expand the user's connectivity and everyday convenience, there are serious security considerations that come into account when using the IoT for distributed authentication. Furthermore the incorporation of biometrics to IoT design brings about concerns of cost and implementing a 'user-friendly' design. In this paper, we focus on the use of electrocardiogram (ECG) signals to implement distributed biometrics authentication within an IoT system model. Our observations show that ECG biometrics are highly reliable, more secure, and easier to implement than other biometrics.

Due to the evolution of LED lighting and information technology, the application of media facades has expanded rapidly. Despite the positive aspects of media facades, the growth of them can cause light pollution and add to the confusion of the city. This study analyzes the Seoul case which implements citywide management with a master plan for media facades. Through this, the study aims to investigate the meaning of citywide management of media facades installed on individual buildings. Firstly, it investigates the conditions of media facades in Seoul City. The identified problems prove the necessity of the citywide management for media facades. Secondly, it analyzed the progress of media facades regulation of Seoul City. Management target has changed from the indiscreet installation for the individual media facades to further inducing the attractive media facade for overall Seoul City. For this, the 'Seoul Media Facade Management MasterPlan' was drafted to establish citywide management by the Seoul government. Thirdly, it analyzed the MasterPlan. The management tools in the MasterPlan are classified into regional management, elemental management, and specialization plans, each having detailed approaches. Finally, the study discussed the meaning of citywide management in the aspect that media facades are the cultural asset to the city, that the regional differentiation is adopted, and that the continuous maintenance for both of the hardware and content) is important. Media facades utilizing the facade of buildings are recognized as an element of urban landscapes securing the publicness, contributing to the vitalization of the area, and finally providing pleasure to the citizens.

Today's mobile app economy has greatly expanded the types of "things" people can share –- spanning from new types of digital content like physiological data (e.g., workouts) to physical things like apartments and work tools ("sharing economy"). To understand whether mobile platforms provide adequate support for such novel sharing services, we surveyed 200 participants about their experiences with six types of emergent sharing services. For each domain we elicited device usage practices and identified corresponding device selection criteria. Our analysis suggests that, despite contemporary mobile first design efforts, desktop interfaces of emergent content sharing services are often considered more efficient and easier to use –- both for sharing and access control tasks (i.e., privacy). Based on our findings, we outline device-related design and research opportunities in this space.

Black-holes, gray-holes and, wormholes, are devastating to the correct operation of any network. These attacks (among others) are based on the premise that packets will travel through compromised nodes, and methods exist to coax routing into these traps. Detection of these attacks are mainly centered around finding the subversion in action. In networks, bottleneck nodes -- those that sit on many potential routes between sender and receiver -- are an optimal location for compromise. Finding naturally occurring path bottlenecks, however, does not entitle network subversion, and as such are more difficult to detect. The dynamic nature of mobile ad-hoc networks (manets) causes ubiquitous routing algorithms to be even more susceptible to this class of attacks. Finding perceived bottlenecks in an olsr based manet, is able to capture between 50%-75% of data. In this paper we propose a method of subtly expanding perceived bottlenecks into complete bottlenecks, raising capture rate up to 99%; albeit, at high cost. We further tune the method to reduce cost, and measure the corresponding capture rate.

Insider threats remain a significant problem within organizations, especially as industries that rely on technology continue to grow. Traditionally, research has been focused on the malicious insider; someone that intentionally seeks to perform a malicious act against the organization that trusts him or her. While this research is important, more commonly organizations are the victims of non-malicious insiders. These are trusted employees that are not seeking to cause harm to their employer; rather, they misuse systems-either intentional or unintentionally-that results in some harm to the organization. In this paper, we look at both by developing and validating instruments to measure the behavior and circumstances of a malicious insider versus a non-malicious insider. We found that in many respects their psychological profiles are very similar. The results are also consistent with other research on the malicious insider from a personality standpoint. We expand this and also find that trait negative affect, both its higher order dimension and the lower order dimensions, are highly correlated with insider threat behavior and circumstances. This paper makes four significant contributions: 1) Development and validation of survey instruments designed to measure the insider threat; 2) Comparison of the malicious insider with the non-malicious insider; 3) Inclusion of trait affect as part of the psychological profile of an insider; 4) Inclusion of a measure for financial well-being, and 5) The successful use of survey research to examine the insider threat problem.

Even though some seem to think privacy is dead, we are all still wearing clothes, as Bruce Schneier observed at a recent conference on surveillance[1]. Yet big data and big data analytics are leaving some of us feeling a bit more naked than before. This talk will provide some personal observations on privacy today and then outline some research areas where progress is needed to enable society to gain the benefits of analyzing large datasets without giving up more privacy than necessary. Not since the early 1970s, when computing pioneer Willis Ware chaired the committee that produced the initial Fair Information Practice Principles [2] has privacy been so much in the U.S. public eye. Snowden's revelations, as well as a growing awareness that merely living our lives seems to generate an expanding "digital exhaust." Have triggered many workshops and meetings. A national strategy for privacy research is in preparation by a Federal interagency group. The ability to analyze large datasets rapidly and to extract commercially useful insights from them is spawning new industries. Must this industrial growth come at the cost of substantial privacy intrusions?

Crowdsourcing is an unique and practical approach to obtain personalized data and content. Its impact is especially significant in providing commentary, reviews and metadata, on a variety of location based services. In this study, we examine reliability of the Waze mapping service, and its vulnerability to a variety of location-based attacks. Our goals are to understand the severity of the problem, shed light on the general problem of location and device authentication, and explore the efficacy of potential defenses. Our preliminary results already show that a single attacker with limited resources can cause havoc on Waze, producing ``virtual'' congestion and accidents, automatically re-routing user traffic, and compromising user privacy by tracking users' precise movements via software while staying undetected. To defend against these attacks, we propose a proximity-based Sybil detection method to filter out malicious devices.

A distributed detection method is proposed to detect single stage multi-point (SSMP) attacks on a Cyber Physical System (CPS). Such attacks aim at compromising two or more sensors or actuators at any one stage of a CPS and could totally compromise a controller and prevent it from detecting the attack. However, as demonstrated in this work, using the flow properties of water from one stage to the other, a neighboring controller was found effective in detecting such attacks. The method is based on physical invariants derived for each stage of the CPS from its design. The attack detection effectiveness of the method was evaluated experimentally against an operational water treatment testbed containing 42 sensors and actuators. Results from the experiments point to high effectiveness of the method in detecting a variety of SSMP attacks but also point to its limitations. Distributing the attack detection code among various controllers adds to the scalability of the proposed method.

Traffic of Industrial Control System (ICS) between the Human Machine Interface (HMI) and the Programmable Logic Controller (PLC) is highly periodic. However, it is sometimes multiplexed, due to multi-threaded scheduling. In previous work we introduced a Statechart model which includes multiple Deterministic Finite Automata (DFA), one per cyclic pattern. We demonstrated that Statechart-based anomaly detection is highly effective on multiplexed cyclic traffic when the individual cyclic patterns are known. The challenge is to construct the Statechart, by unsupervised learning, from a captured trace of the multiplexed traffic, especially when the same symbols (ICS messages) can appear in multiple cycles, or multiple times in a cycle. Previously we suggested a combinatorial approach for the Statechart construction, based on Euler cycles in the Discrete Time Markov Chain (DTMC) graph of the trace. This combinatorial approach worked well in simple scenarios, but produced a false-alarm rate that was excessive on more complex multiplexed traffic. In this paper we suggest a new Statechart construction method, based on spectral analysis. We use the Fourier transform to identify the dominant periods in the trace. Our algorithm then associates a set of symbols with each dominant period, identifies the order of the symbols within each period, and creates the cyclic DFAs and the Statechart. We evaluated our solution on long traces from two production ICS: one using the Siemens S7-0x72 protocol and the other using Modbus. We also stress-tested our algorithms on a collection of synthetically-generated traces that simulate multiplexed ICS traces with varying levels of symbol uniqueness and time overlap. The resulting Statecharts model the traces with an overall median false-alarm rate as low as 0.16% on the synthetic datasets, and with zero false-alarms on production S7-0x72 traffic. Moreover, the spectral analysis Statecharts consistently out-performed the previous combinatorial Statecharts, exhibiting significantly lower false alarm rates and more compact model sizes.

In this paper, we propose a hierarchical monitoring intrusion detection system (HAMIDS) for industrial control systems (ICS). The HAMIDS framework detects the anomalies in both level 0 and level 1 of an industrial control plant. In addition, the framework aggregates the cyber-physical process data in one point for further analysis as part of the intrusion detection process. The novelty of this framework is its ability to detect anomalies that have a distributed impact on the cyber-physical process. The performance of the proposed framework evaluated as part of SWaT security showdown (S3) in which six international teams were invited to test the framework in a real industrial control system. The proposed framework outperformed other proposed academic IDS in term of detection of ICS threats during the S3 event, which was held from July 25-29, 2016 at Singapore University of Technology and Design.

We propose a modification to the framework of Universally Composable (UC) security [3]. Our new notion involves comparing the real protocol execution with an ideal execution involving ideal functionalities (just as in UC-security), but allowing the environment and adversary access to some super-polynomial computational power. We argue the meaningfulness of the new notion, which in particular subsumes many of the traditional notions of security. We generalize the Universal Composition theorem of [3] to the new setting. Then under new computational assumptions, we realize secure multi-party computation (for static adversaries) without a common reference string or any other set-up assumptions, in the new framework. This is known to be impossible under the UC framework.

Protocols for authenticated key exchange (AKE) allow parties within an insecure network to establish a common session key which can then be used to secure their future communication. It is fair to say that group AKE is currently less well understood than the case of two-party AKE; in particular, attacks by malicious insiders –- a concern specific to the group setting –- have so far been considered only in a relatively "ad-hoc" fashion. The main contribution of this work is to address this deficiency by providing a formal, comprehensive model and definition of security for group AKE which automatically encompasses insider attacks. We do so by defining an appropriate ideal functionality for group AKE within the universal composability (UC) framework. As a side benefit, any protocol secure with respect to our definition is secure even when run concurrently with other protocols, and the key generated by any such protocol may be used securely in any subsequent application.In addition to proposing this definition, we show that the resulting notion of security is strictly stronger than the one proposed by Bresson, et al. (termed "AKE-security"), and that our definition implies all previously-suggested notions of security against insider attacks. We also show a simple technique for converting any AKE-secure protocol into one secure with respect to our definition.

Syntax extension mechanisms are powerful, but reasoning about syntax extensions can be difficult. Recent work on type-specific languages (TSLs) addressed reasoning about composition, hygiene and typing for extensions introducing new literal forms. We supplement TSLs with typed syntax macros (TSMs), which, unlike TSLs, are explicitly invoked to give meaning to delimited segments of arbitrary syntax. To maintain a typing discipline, we describe two avors of term-level TSMs: synthetic TSMs specify the type of term that they generate, while analytic TSMs can generate terms of arbitrary type, but can only be used in positions where the type is otherwise known. At the level of types, we describe a third avor of TSM that generates a type of a specified kind along with its TSL and show interesting use cases where the two mechanisms operate in concert.

We propose a lightweight RFID authentication protocol that supports forward and backward security. The only cryptographic mechanism that this protocol uses is a pseudorandom number generator (PRNG) that is shared with the backend Server. Authentication is achieved by exchanging a few numbers (3 or 5) drawn from the PRNG. The lookup time is constant, and the protocol can be easily adapted to prevent online man-in-the-middle relay attacks. Security is proven in the UC security framework.

Though anonymity of ring signature schemes has been studied in many literatures for a long time, these papers showed different definitions and there is no consensus. Recently, Bender et al. proposed two new anonymity definitions of ring signature which is stronger than the traditional definition, that are called anonymity against attribution attacks/full key exposure. Also, ring signature schemes have two levels of unforgeability definitions, i.e., existential un-forgeability (eUF) and strong existential unforgeability (sUF). In this paper, we will redefine anonymity and unforgeability definitions from the standpoint of universally composable (UC) security framework. First, we will formulate new ideal functionalities of ring signature schemes for each security levels separately. Next, we will show relations between cryptographic security definitions and our UC definitions. Finally, we will give another proof of the Bender et al.'s ring signature scheme following the UC secure definition by constructing a simulator to an adversary of sUF, which can be adaptable to the case of sUF under the assumption of a standard single sUF signature scheme.

A two-server password-based authentication (2PA) protocol is a special kind of authentication primitive that provides additional protection for the user's password. Through a 2PA protocol, a user can distribute his low-entropy password between two authentication servers in the initialization phase and authenticate himself merely via a matching password in the login phase. No single server can learn any information about the user's password, nor impersonate the legitimate user to authenticate to the honest server. In this paper, we first formulate and realize the security definition of two-server password-based authentication in the well-known universal composability (UC) framework, which thus provides desirable properties such as composable security. We show that our construction is suitable for the asymmetric communication model in which one server acts as the front-end server interacting directly with the user and the other stays backstage. Then, we show that our protocol could be easily extended to more complicate password-based cryptographic protocols such as two-server password-authenticated key exchange (2PAKE) and two-server password-authenticated secret sharing (2PASS), which enjoy stronger security guarantees and better efficiency performances in comparison with the existing schemes.

Compositional theories and technologies facilitate the decomposition of a complex system into components, as well as their integration via interfaces. Component interfaces hide the internal details of the components, thereby reducing integration complexity. A system is said to be composable if the properties established and validated for components in isolation hold once the components are integrated to form the system. This brings us the question: "Is compositionality related to composability?" This paper answers this question in the affirmative; it considers a previously known interface for compositionality and shows that it can be used for composability. It also presents a run-time policing mechanism for this interface.

Computational soundness results show that under certain conditions it is possible to conclude computational security whenever symbolic security holds. Unfortunately, each soundness result is usually established for some set of cryptographic primitives and extending the result to encompass new primitives typically requires redoing most of the work. In this paper we suggest a way of getting around this problem. We propose a notion of computational soundness that we term deduction soundness. As for other soundness notions, our definition captures the idea that a computational adversary does not have any more power than a symbolic adversary. However, a key aspect of deduction soundness is that it considers, intrinsically, the use of the primitives in the presence of functions specified by the adversary. As a consequence, the resulting notion is amenable to modular extensions. We prove that a deduction sound implementation of some arbitrary primitives can be extended to include asymmetric encryption and public data-structures (e.g. pairings or list), without repeating the original proof effort. Furthermore, our notion of soundness concerns cryptographic primitives in a way that is independent of any protocol specification language. Nonetheless, we show that deduction soundness leads to computational soundness for languages (or protocols) that satisfy a so called commutation property.

Many solutions for composability and compositionality rely on specifying the interface for a component using bandwidth. Some previous works specify period (P) and budget (Q) as an interface for a component. Q/P provides us with a bandwidth (the share of a processor that this component may request); P specifies the time-granularity of the allocation of this processing capacity. Other works add another parameter deadline which can help to provide tighter bounds on how this processing capacity is distributed. Yet other works use the parameters α and Δ where α is the bandwidth and Δ specifies how smoothly this bandwidth is distributed. It is known [4] that such bandwidth-like interfaces carry a cost: there are tasksets that could be guaranteed to be schedulable if tasks were scheduled directly on the processor, but with bandwidth-like interfaces, it is impossible to guarantee the taskset to be schedulable. And it is also known that this penalty can be infinite, i.e., the use of bandwidth-like interfaces may require the use of a processor that has a speed that is k times faster, and one can show this for any k. This brings the question: "What is the average-case performance penalty of bandwidth-like interfaces?" This paper addresses this question. We answer the question by randomly generating tasksets and then for each of these tasksets, compute a lower bound on how much faster a processor needs to be when a bandwidth-like scheme is used. We do not consider any specific bandwidth-like scheme; instead, we derive an expression that states a lower bound on how much faster a processor needs to be when a bandwidth-like scheme is used. For the distributions considered in this paper, we find that (i) the experimental results depend on the experimental setup, (ii) this lower bound on the penalty was never larger than 4.0, (iii) for one experimental setup, for each taskset, it was greater than 2.4, (iv) the histogram of this penalty appears to be unimodal, and (v) for implicit-deadline sporadic tasks, this lower bound on the penalty was exactly 1.

This paper introduces typy, a statically typed programming language embedded by reflection into Python. typy features a fragmentary semantics, i.e. it delegates semantic control over each term, drawn from Python's fixed concrete and abstract syntax, to some contextually relevant user-defined semantic fragment. The delegated fragment programmatically 1) typechecks the term (following a bidirectional protocol); and 2) assigns dynamic meaning to the term by computing a translation to Python. We argue that this design is expressive with examples of fragments that express the static and dynamic semantics of 1) functional records; 2) labeled sums (with nested pattern matching a la ML); 3) a variation on JavaScript's prototypal object system; and 4) typed foreign interfaces to Python and OpenCL. These semantic structures are, or would need to be, defined primitively in conventionally structured languages. We further argue that this design is compositionally well-behaved. It avoids the expression problem and the problems of grammar composition because the syntax is fixed. Moreover, programs are semantically stable under fragment composition (i.e. defining a new fragment will not change the meaning of existing program components.)