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Explainable AI provides insights to users into the why for model predictions, offering potential for users to better understand and trust a model, and to recognize and correct AI predictions that are incorrect. Prior research on human and explainable AI interactions has focused on measures such as interpretability, trust, and usability of the explanation. There are mixed findings whether explainable AI can improve actual human decision-making and the ability to identify the problems with the underlying model. Using real datasets, we compare objective human decision accuracy without AI (control), with an AI prediction (no explanation), and AI prediction with explanation. We find providing any kind of AI prediction tends to improve user decision accuracy, but no conclusive evidence that explainable AI has a meaningful impact. Moreover, we observed the strongest predictor for human decision accuracy was AI accuracy and that users were somewhat able to detect when the AI was correct vs. incorrect, but this was not significantly affected by including an explanation. Our results indicate that, at least in some situations, the why information provided in explainable AI may not enhance user decision-making, and further research may be needed to understand how to integrate explainable AI into real systems.

Events such as Facebook-Cambridge Analytica scandal and data aggregation efforts by technology providers have illustrated how fragile modern society is to privacy violations. Internationally recognized entities such as the National Science Foundation (NSF) have indicated that Artificial Intelligence (AI)-enabled models, artifacts, and systems can efficiently and effectively sift through large quantities of data from legal documents, social media, Dark Web sites, and other sources to curb privacy violations. Yet considerable efforts are still required for understanding prevailing data sources, systematically developing AI-enabled privacy analytics to tackle emerging challenges, and deploying systems to address critical privacy needs. To this end, we provide an overview of prevailing data sources that can support AI-enabled privacy analytics; a multi-disciplinary research framework that connects data, algorithms, and systems to tackle emerging AI-enabled privacy analytics challenges such as entity resolution, privacy assistance systems, privacy risk modeling, and more; a summary of selected funding sources to support high-impact privacy analytics research; and an overview of prevailing conference and journal venues that can be leveraged to share and archive privacy analytics research. We conclude this paper with an introduction of the papers included in this special issue.

In recent years, as online social networks continue to grow in size, estimating node features, such as sociodemographics, preferences and health status, in a scalable and reliable way has become a primary research direction in social network mining. Although many techniques have been developed for estimating various node features, quantifying uncertainty in such estimations has received little attention. Furthermore, most existing methods study networks parametrically, which limits insights about necessary quantity of queried data, reliable feature estimation, and estimator uncertainty. Uncertainty quantification is critical for answering key questions, such as, given a limited availability of social network data, how much data should be queried from the network?, and which node features can be learned reliably? More importantly, how can we evaluate uncertainty of our estimators? Uncertainty quantification is not equivalent to network sampling but constitutes a key complementary concept to sampling and the associated reliability analysis. To our knowledge, this paper is the first work that sheds light on uncertainty quantification and uncertainty propagation in social network feature mining. We propose a novel non-parametric bootstrap method for uncertainty analysis of node features in social network mining, derive its asymptotic properties, and demonstrate its effectiveness with extensive experiments. Furthermore, we develop a new metric based on dispersion of estimations, enabling analysts to assess how much more information is needed for increasing prediction reliability based on the estimated uncertainty. We demonstrate the effectiveness of our new uncertainty quantification methodology with extensive experiments on real life social networks, and a case study of mental health on Twitter.

Cybersecurity has rapidly emerged as a grand societal challenge of the 21st century. Innovative solutions to proactively tackle emerging cybersecurity challenges are essential to ensuring a safe and secure society. Artificial Intelligence (AI) has rapidly emerged as a viable approach for sifting through terabytes of heterogeneous cybersecurity data to execute fundamental cybersecurity tasks, such as asset prioritization, control allocation, vulnerability management, and threat detection, with unprecedented efficiency and effectiveness. Despite its initial promise, AI and cybersecurity have been traditionally siloed disciplines that relied on disparate knowledge and methodologies. Consequently, the AI for Cybersecurity discipline is in its nascency. In this article, we aim to provide an important step to progress the AI for Cybersecurity discipline. We first provide an overview of prevailing cybersecurity data, summarize extant AI for Cybersecurity application areas, and identify key limitations in the prevailing landscape. Based on these key issues, we offer a multi-disciplinary AI for Cybersecurity roadmap that centers on major themes such as cybersecurity applications and data, advanced AI methodologies for cybersecurity, and AI-enabled decision making. To help scholars and practitioners make significant headway in tackling these grand AI for Cybersecurity issues, we summarize promising funding mechanisms from the National Science Foundation (NSF) that can support long-term, systematic research programs. We conclude this article with an introduction of the articles included in this special issue.

Private record linkage protocols allow multiple parties to exchange matching records, which refer to the same entities or have similar values, while keeping the non-matching ones secret. Conventional protocols are based on computationally expensive cryptographic primitives and therefore do not scale. To address these scalability issues, hybrid protocols have been proposed that combine differential privacy techniques with secure multiparty computation techniques. However, a drawback of such protocols is that they disclose to the parties both the matching records and the differentially private synopses of the datasets involved in the linkage. Consequently, differential privacy is no longer always satisfied. To address this issue, we propose a novel framework that separates the private synopses from the matching records. The two parties do not access the synopses directly, but still use them to efficiently link records. We theoretically prove the security of our framework under the state-of-the-art privacy notion of differential privacy for record linkage (DPRL). In addition, we develop a simple but effective strategy for releasing private synopses. Extensive experimental results show that our framework is superior to the existing methods in terms of efficiency.

Blockchain technology garners an ever-increasing interest of researchers in various domains that benefit from scalable cooperation among trust-less parties. As blockchains and their applications proliferate, so do the complexity and volume of data stored by Blockchains. Analyzing this data has emerged as an important research topic, already leading to methodological advancements in information sciences. In this tutorial, we offer a holistic view of applied Data Science on Blockchains. Starting with the core components of Blockchain, we will detail the state of art in Blockchain data analytics for graph, security, and finance domains. Our examples will answer questions, such as, how to parse, extract and clean the data stored in blockchains?, how to store and query Blockchain data? and what features we could compute from blockchains? We will share tutorial notes, collected meta-information, and further reading pointers on our tutorial website at https://blockchaintutorial.github.io/

Core decomposition in networks has proven useful for evaluating the importance of nodes and communities in a variety of application domains, ranging from biology to social networks and finance. However, existing core decomposition algorithms have limitations in simultaneously handling multiple node and edge attributes. We propose a novel unsupervised core decomposition method that can be easily applied to directed and weighted networks. Our algorithm, AlphaCore, allows us to systematically and mathematically rigorously combine multiple node properties by using the notion of data depth. In addition, it can be used as a mixture of centrality measure and core decomposition. Compared to existing approaches, AlphaCore avoids the need to specify numerous thresholds or coefficients and yields meaningful quantitative and qualitative insights into the network structural organization. We evaluate AlphaCore's performance with a focus on financial, blockchain-based token networks, the social network Reddit and a transportation network of international flight routes. We compare our results with existing core decomposition and centrality algorithms. Using ground truth about node importance, we show that AlphaCore yields the best precision and recall results among core decomposition methods using the same input features. An implementation is available at https://github.com/friedhelmvictor/alphacore.

The growing adoption of IoT devices in our daily life is engendering a data deluge, mostly private information that needs careful maintenance and secure storage system to ensure data integrity and protection. Also, the prodigious IoT ecosystem has provided users with opportunities to automate systems by interconnecting their devices and other services with rule-based programs. The cloud services that are used to store and process sensitive IoT data turn out to be vulnerable to outside threats. Hence, sensitive IoT data and rule-based programs need to be protected against cyberattacks. To address this important challenge, in this paper, we propose a framework to maintain confidentiality and integrity of IoT data and rule-based program execution. We design the framework to preserve data privacy utilizing Trusted Execution Environment (TEE) such as Intel SGX, and end-to-end data encryption mechanism. We evaluate the framework by executing rule-based programs in the SGX securely with both simulated and real IoT device data.

Background Blockchain has emerged as a decentralized and distributed framework that enables tamper-resilience and, thus, practical immutability for stored data. This immutability property is important in scenarios where auditability is desired, such as in maintaining access logs for sensitive healthcare and biomedical data. However, the underlying data structure of blockchain, by default, does not provide capabilities to efficiently query the stored data. In this investigation, we show that it is possible to efficiently run complex audit queries over the access log data stored on blockchains by using additional key-value stores. This paper specifically reports on the approach we designed for the blockchain track of iDASH Privacy & Security Workshop 2018 competition. In this track, participants were asked to devise an efficient way to run conjunctive equality and range queries on a genomic dataset access log trail after storing it in a permissioned blockchain network consisting of 4 identical nodes, each representing a different site, created with the Multichain platform. Methods Multichain duplicates and indexes blockchain data locally at each node in a key-value store to support retrieval requests at a later point in time. To efficiently leverage the key-value storage mechanism, we applied various techniques and optimizations, such as bucketization, simple data duplication and batch loading by accounting for the required query types of the competition and the interface provided by Multichain. Particularly, we implemented our solution and compared its loading and query-response performance with SQLite, a commonly used relational database, using the data provided by the iDASH 2018 organizers. Results Depending on the query type and the data size, the run time difference between blockchain based query-response and SQLite based query-response ranged from 0.2 seconds to 6 seconds. A deeper inspection revealed that range queries were the bottleneck of our solution which, nevertheless, scales up linearly. Conclusions This investigation demonstrates that blockchain-based systems can provide reasonable query-response times to complex queries even if they only use simple key-value stores to manage their data. Consequently, we show that blockchains may be useful for maintaining data with auditability and immutability requirements across multiple sites.

Part 6: Secure Outsourcing and Privacy; International audience; To preserve the security and the privacy of the data need for cloud applications, encrypting the data before outsourcing has emerged as an important tool. Furthermore, to enable efficient processing over the encrypted data stored in the cloud, utilizing efficient searchable symmetric encryption (SSE) schemes became popular. Usually, SSE schemes require an encrypted index to be built for efficient query processing. If the data owner has limited power, building this encrypted index before data is outsourced to the cloud could become a computational bottleneck. At the same time, secure outsourcing of encrypted index building using techniques such as homomorphic encryption is too costly for large data. Instead, in this work, we use a trusted processor, e.g, Intel Software Guard eXtension (SGX), to build a secure information retrieval system that provides better security guarantee and performance improvements. Unlike other related works, we focus on securely building the encrypted index in the cloud computing environment using the SGX, and show that the encrypted index could be used for executing keyword queries over text documents and face recognition detection in image documents. Finally, we show the effectiveness of our system via extensive empirical evaluation.

Cryptographic API misuses seriously threatens software security. Automatic screening of cryptographic misuse vulnerabilities has been a popular and important line of research over the years. However, the vision of producing a scalable detection tool that developers can routinely use to screen millions of line of code has not been achieved yet. Our main technical goal is to attain a high precision and high throughput approach based on specialized program analysis. Specifically, we design inter-procedural program slicing on top of a new on-demand flow-, context- and field- sensitive data flow analysis. Our current prototype named CryptoGuard can detect a wide range of Java cryptographic API misuses with a precision of 98.61%, when evaluated on 46 complex Apache Software Foundation projects (including, Spark, Ranger, and Ofbiz). Our evaluation on 6,181 Android apps also generated many security insights. We created a comprehensive benchmark named CryptoApi-Bench with 40-unit basic cases and 131-unit advanced cases for in-depth comparison with leading solutions (e.g., SpotBugs, CrySL, Coverity). To make CryptoGuard widely accessible, we are in the process of integrating CryptoGuard with the Software Assurance Marketplace (SWAMP). SWAMP is a popular no-cost service for continuous software assurance and static code analysis.

With a spatial statistical database covering a large region, how to publish differential privacy protected information is a challenge. In previous works, information was published using large fixed spatial cells. In this paper, we develop novel flexible methods to publish the spatial information, which allows the users to freely move around the large region, zoom in and zoom out at arbitrary locations, and obtain information over spatial areas both large and small. We develop two methods to publish the spatial information protected under differential privacy. First the region is divided into the smallest spatial cells, where each cell does not observe an event happening more than once. Given repeated measurements, such as multiple day data, the noise added Bernoulli probabilities are computed for all the smallest spatial cells. For larger spatial cells of high interests to users, the noisy Bernoulli probabilities are combined into noisy Poisson-Binomial distributions which also satisfy differential privacy requirement. We use the New York Taxi data in the experiments to demonstrate how our methods work. We show that both of our methods are accurate, while the noisy count probabilities directly obtained from fixed large spatial cells often generate the spatial counts much smaller than the true values.

Inference problem has always been an important and challenging topic of data privacy in databases. In relational databases, the traditional solution to this problem was to define views on relational schemas to restrict the subset of attributes and operations available to the users in order to prevent unwanted inferences. This method is a form of decomposition strategy, which mainly concentrates on the granularity of the accessible fields to the users, to prevent sensitive information inference. Nowadays, due to increasing data sharing among parties, the possibility of constructing complex indirect methods to obtain sensitive data has also increased. Therefore, we need to not only consider security threats due to direct access to sensitive data but also address indirect inference channels using functional and probabilistic dependencies (e.g., deducing gender of an individual from his/her name) while creating security views. In this paper, we propose a proactive and decomposition based inference control strategy for relational databases to prevent direct or indirect inference of private data. We introduce a new kind of context dependent attribute policy rule, which is named as security dependent set, as a set of attributes whose association should not be inferred. Then, we define a logical schema decomposition algorithm that prevents inference among attributes in security dependent set. The decomposition algorithm takes both functional and probabilistic dependencies into consideration in order to prevent all kinds of known inferences of relations among the attributes of security dependent sets. We prove that our proposed decomposition algorithm generates a secure logical schema that complies with the given security dependent set constraints. Since our proposed technique is purely proactive, it does not require any prior knowledge about executed queries and do not need to modify any submitted queries. It can also be embedded into any relational database management system without changing anything in the underlying system. We empirically compare our proposed method with the state of art reactive methods. Our extensive experimental analysis, conducted using TPC-H 1 benchmark scheme, shows the effectives our proposed approach.

The following is a survey on surveys and may help the interested reader to find a way through the jungle of literature on the security and CPS topics out there already. In order to ease the search, the authors have provided a classification in CPS Domains, Attacks, Defenses, Research-trends, Network-security, Security level implementation, and Computational Strategies which makes this survey a unique and I believe very helpful article. —Jorg Henkel, Karlsruhe Institute of Technology

As machine learning (ML) techniques are becoming widely used, awareness of the harmful effect of automation is growing. Especially, in problem domains where critical decisions are made, machine learning-based applications may raise ethical issues with respect to fairness and privacy. Existing research on fairness and privacy in the ML community mainly focuses on providing remedies during the ML model training phase. Unfortunately, such remedies may not be voluntarily adopted by the industry that is concerned about the profits. In this paper, we propose to apply, from the user’s end, a fair and legitimate technique to “game” the ML system to ameliorate its social accountability issues. We show that although adversarial attacks can be exploited to tamper with ML systems, they can also be used for social good. We demonstrate the effectiveness of our proposed technique on real world image and credit data.

Federated Learning (FL) is a distributed, and decentralized machine learning protocol. By executing FL, a set of agents can jointly train a model without sharing their datasets with each other, or a third-party. This makes FL particularly suitable for settings where data privacy is desired. At the same time, concealing training data gives attackers an opportunity to inject backdoors into the trained model. It has been shown that an attacker can inject backdoors to the trained model during FL, and then can leverage the backdoor to make the model misclassify later. Several works tried to alleviate this threat by designing robust aggregation functions. However, given more sophisticated attacks are developed over time, which by-pass the existing defenses, we approach this problem from a complementary angle in this work. Particularly, we aim to discourage backdoor attacks by detecting, and punishing the attackers, possibly after the end of training phase. To this end, we develop a hybrid blockchain-based FL framework that uses smart contracts to automatically detect, and punish the attackers via monetary penalties. Our framework is general in the sense that, any aggregation function, and any attacker detection algorithm can be plugged into it. We conduct experiments to demonstrate that our framework preserves the communication-efficient nature of FL, and provide empirical results to illustrate that it can successfully penalize attackers by leveraging our novel attacker detection algorithm.

Cryptographic API misuses, such as exposed secrets, predictable random numbers, and vulnerable certificate verification, seriously threaten software security. The vision of automatically screening cryptographic API calls in massive-sized (e.g., millions of LoC) programs is not new. However, hindered by the practical difficulty of reducing false positives without compromising analysis quality, this goal has not been accomplished. CryptoGuard is a set of detection algorithms that refine program slices by identifying language-specific irrelevant elements. The refinements reduce false alerts by 76% to 80% in our experiments. Running our tool, CryptoGuard, on 46 high-impact large-scale Apache projects and 6,181 Android apps generated many security insights. Our findings helped multiple popular Apache projects to harden their code, including Spark, Ranger, and Ofbiz. We also have made progress towards the science of analysis in this space, including manually analyzing 1,295 Apache alerts, confirming 1,277 true positives (98.61% precision), and in-depth comparison with leading solutions including CrySL, SpotBugs, and Coverity.

Cryptographic API misuses seriously threaten software security. Automatic screening of cryptographic misuse vulnerabilities has been a popular and important line of research over the years. However, the vision of producing a scalable detection tool that developers can routinely use to screen millions of line of code has not been achieved yet. Our main technical goal is to attain a high precision and high throughput approach based on specialized program analysis. Specifically, we design inter-procedural program slicing on top of a new on-demand flow-, context- and field- sensitive data flow analysis. Our current prototype named CryptoGuard can detect a wide range of Java cryptographic API misuses with a precision of 98.61%,, when evaluated on 46 complex Apache Software Foundation projects (including, Spark, Ranger, and Ofbiz). Our evaluation on 6,181 Android apps also generated many security insights. We created a comprehensive benchmark named CryptoAPI-Bench with 40-unit basic cases and 131-unit advanced cases for in-depth comparison with leading solutions (e.g., SpotBugs, CrySL, Coverity). To make CryptoGuard widely accessible, we are in the process of integrating CryptoGuard with the Software Assurance Marketplace (SWAMP). SWAMP is a popular no-cost service for continuous software assurance and static code analysis.

With emergence of blockchain technologies and the associated cryptocurrencies, such as Bitcoin, understanding network dynamics behind Blockchain graphs has become a rapidly evolving research direction. Unlike other financial networks, such as stock and currency trading, blockchain based cryptocurrencies have the entire transaction graph accessible to the public (i.e., all transactions can be downloaded and analyzed). A natural question is then to ask whether the dynamics of the transaction graph impacts the price of the underlying cryptocurrency. We show that standard graph features such as degree distribution of the transaction graph may not be sufficient to capture network dynamics and its potential impact on fluctuations of Bitcoin price. In contrast, the new graph associated topological features computed using the tools of persistent homology, are found to exhibit a high utility for predicting Bitcoin price dynamics. %explain higher order interactions among the nodes in Blockchain graphs and can be used to build much more accurate price prediction models. Using the proposed persistent homology-based techniques, we offer a new elegant, easily extendable and computationally light approach for graph representation learning on Blockchain., To Appear in the 2019 IEEE International Conference on Data Mining (ICDM)

We present a robust active learning technique for situations where there are weak and adversarial oracles. Our work falls under the general umbrella of active learning in which training data is insufficient and oracles are queried to supply labels for the most informative samples to expand the training set. On top of that, we consider problems where a large percentage of oracles may be strategically lying, as in adversarial settings. We present an adversarial active learning technique that explores the duality between oracle modeling and data modeling. We demonstrate on real datasets that our adversarial active learning technique is superior to not only the heuristic majority-voting technique but one of the state-of-the-art adversarial crowdsourcing technique—Generative model of Labels, Abilities, and Difficulties (GLAD), when genuine oracles are outnumbered by weak oracles and malicious oracles, and even in the extreme cases where all the oracles are either weak or malicious. To put our technique under more rigorous tests, we compare our adversarial active learner to the ideal active learner that always receives correct labels. We demonstrate that our technique is as effective as the ideal active learner when only one third of the oracles are genuine.

Record linkage is the process of integrating information from the same underlying entity across disparate data sets. This process, which is increasingly utilized to build accurate representations of individuals and organizations for a variety of applications, ranging from credit worthiness assessments to continuity of medical care, can be computationally intensive because it requires comparing large quantities of records over a range of attributes. To reduce the amount of computation in record linkage in big data settings, blocking methods, which are designed to limit the number of record pair comparisons that needs to be performed, are critical for scaling up the record linkage process. These methods group together potential matches into blocks, often using a subset of attributes before a final comparator function predicts which record pairs within the blocks correspond to matches. Yet data corruption and missing values adversely influence the performance of blocking methods (e.g., it may cause some matching records not to be placed in the same block). While there has been some investigation into the impact of missing values on general record linkage techniques (e.g., the comparator function), no study has addressed the impact of the missing values on blocking methods. To address this issue, in this work, we systematically perform a detailed empirical analysis of the individual and joint impact of missing values and data corruption on different blocking methods using realistic data sets. Our results show that blocking approaches that do not depend on one type of blocking attributes are more robust against missing values. In addition, our results indicate that blocking parameters must be chosen carefully for different blocking techniques.

Over the last couple of years, Bitcoin cryptocurrency and the Blockchain technology that forms the basis of Bitcoin have witnessed an unprecedented attention. Designed to facilitate a secure distributed platform without central regulation, Blockchain is heralded as a novel paradigm that will be as powerful as Big Data, Cloud Computing, and Machine Learning. The Blockchain technology garners an ever increasing interest of researchers in various domains that benefit from scalable cooperation among trust-less parties. As Blockchain data analytics further proliferates, a need to glean successful approaches and to disseminate them among a diverse body of data scientists became a critical task. As an inter-disciplinary team of researchers, our aim is to fill this vital role. In this tutorial, we offer a holistic view on Blockchain Data Analytics. Starting with the core components of Blockchain, we will discuss the state of art in Blockchain data analytics for privacy, security, finance, and management domains. We will share tutorial notes and further reading pointers on the tutorial website blockchaintutorial.github.io.

We introduce attacklets, a novel approach to model the high dimensional interactions in cyberattacks. Attacklets are implemented using a real-world dataset of cyberattacks from the Verizon Data Breach Investigation Report. Whereas the commonly used attack graphs model the action sequences of attackers for specific exploits, attacklets model general attributes and states of each attack separately. Attacklets may inform the number and types of attributes across a wide range of cyberattacks. These structural properties can then be used in machine learning models to classify and predict future cyberattacks.

As more and more data is collected for various reasons, the sharing of such data becomes paramount to increasing its value. Many applications ranging from smart cities to personalized health care require individuals and organizations to share data at an unprecedented scale. Data sharing is crucial in today's world, but due to privacy reasons, security concerns and regulation issues, the conditions under which the sharing occurs needs to be carefully specified. Currently, this process is done by lawyers and requires the costly signing of legal agreements. In many cases, these data sharing agreements are hard to track, manage or enforce. In this work, we propose a novel alternative for tracking, managing and especially adjudicating such data sharing agreements using smart contracts and blockchain technology. We design a framework that generates smart contracts from parameters based on legal data sharing agreements. The terms in these agreements are automatically adjudicating by the system. Monetary punishment can be employed using secure voting by external auditors to hold the violators accountable. Our experimental evaluation shows that our proposed framework is efficient and low-cost.

Massive amounts of data are being collected, stored, and analyzed for various business and marketing purposes. While such data analysis is critical for many applications, it could also violate the privacy of individuals. This paper describes the issues involved in designing a privacy aware data management framework for collecting, storing, and analyzing the data. We also discuss behavioral aspects of data sharing as well as aspects of a formal framework based on rewriting rules that encompasses the privacy aware data management framework.

Cyber security and data science are two of the fastest growing fields in Computer Science and more recently they are being integrated for various applications. This position paper will review the developments in applying Data science for cyber security and cyber security for data science and then discuss the applications in Social Media.

Crowdsourcing has raised several security concerns. One of the concerns is how to assign sensitive tasks in the crowdsourcing market, especially when there are colluding participants in crowdsourcing. In this paper, we consider adversarial colluding participants who intend to extract sensitive data by exchanging information. We design a 3-step sensitive task assignment method: (1) the collusion estimation step that quantifies the workers' pairwise collusion probability by estimating answer truth based on their responses; (2) the worker selection step that executes a heuristic sampling-based approach to select the fewest workers whose collusion probability satisfies the given security requirement; and (3) the task partitioning step that splits the sensitive information among the selected workers. We perform an extensive set of experiments on both real-world and synthetic datasets. The results demonstrate the accuracy and efficiency of our method.

Blockchain technology has evolved from being an immutable ledger of transactions for cryptocurrencies to a programmable interactive environment for building distributed reliable applications. Although the blockchain technology has been used to address various challenges, to our knowledge none of the previous work focused on using Blockchain to develop a secure and immutable scientific data provenance management framework that automatically verifies the provenance records. In this work, we leverage Blockchain as a platform to facilitate trustworthy data provenance collection, verification, and management. The developed system utilizes smart contracts and open provenance model (OPM) to record immutable data trails. We show that our proposed framework can securely capture and validate provenance data that prevents any malicious modification to the captured data as long as the majority of the participants are honest.

Display Omitted We present a privacy-preserving protocol to detect concurrent trial participants.We present a name representation scheme resilient to frequency attacks.The accuracy of the protocol is similar to standard non-secure methods.For a database size of 20,000, the private query time is under 40s on 32 cores. ObjectiveSome phase 1 clinical trials offer strong financial incentives for healthy individuals to participate in their studies. There is evidence that some individuals enroll in multiple trials concurrently. This creates safety risks and introduces data quality problems into the trials. Our objective was to construct a privacy preserving protocol to track phase 1 participants to detect concurrent enrollment. DesignA protocol using secure probabilistic querying against a database of trial participants that allows for screening during telephone interviews and on-site enrollment was developed. The match variables consisted of demographic information. MeasurementThe accuracy (sensitivity, precision, and negative predictive value) of the matching and its computational performance in seconds were measured under simulated environments. Accuracy was also compared to non-secure matching methods. ResultsThe protocol performance scales linearly with the database size. At the largest database size of 20,000 participants, a query takes under 20s on a 64 cores machine. Sensitivity, precision, and negative predictive value of the queries were consistently at or above 0.9, and were very similar to non-secure versions of the protocol. ConclusionThe protocol provides a reasonable solution to the concurrent enrollment problems in phase 1 clinical trials, and is able to ensure that personal information about participants is kept secure.

In this paper, we investigate whether decision trees can be used to interpret a black-box classifier without knowing the learning algorithm and the training data. Decision trees are known for their transparency and high expressivity. However, they are also notorious for their instability and tendency to grow excessively large. We present a classifier reverse engineering model that outputs a decision tree to interpret the black-box classifier. There are two major challenges. One is to build such a decision tree with controlled stability and size, and the other is that probing the black-box classifier is limited for security and economic reasons. Our model addresses the two issues by simultaneously minimizing sampling cost and classifier complexity. We present our empirical results on four real datasets, and demonstrate that our reverse engineering learning model can effectively approximate and simplify the black box classifier.

Over the last couple of years, Bitcoin cryptocurrency and the Blockchain technology that forms the basis of Bitcoin have witnessed a flood of attention. In contrast to fiat currencies used worldwide, the Bitcoin distributed ledger is publicly available by design. This facilitates observing all financial interactions on the network, and analyzing how the network evolves in time. We introduce a novel concept of chainlets, or Bitcoin subgraphs, which allows us to evaluate the local topological structure of the Bitcoin graph over time. Furthermore, we assess the role of chainlets on Bitcoin price formation and dynamics. We investigate the predictive Granger causality of chainlets and identify certain types of chainlets that exhibit the highest predictive influence on Bitcoin price and investment risk.

A wide variety of personal data is routinely collected by numerous organizations that, in turn, share and sell their collections for analytic investigations (e.g., market research). To preserve privacy, certain identifiers are often redacted, perturbed or even removed. A substantial number of attacks have shown that, if care is not taken, such data can be linked to external resources to determine the explicit identifiers (e.g., personal names) or infer sensitive attributes (e.g., income) for the individuals from whom the data was collected. As such, organizations increasingly rely upon record linkage methods to assess the risk such attacks pose and adopt countermeasures accordingly. Traditional linkage methods assume only two datasets would be linked (e.g., linking de-identified hospital discharge to identified voter registration lists), but with the advent of a multi-billion dollar data broker industry, modern adversaries have access to a massive data stash of multiple datasets that can be leveraged. Still, realistic adversaries have budget constraints that prevent them from obtaining and integrating all relevant datasets. Thus, in this work, we investigate a novel privacy risk assessment framework, based on adversaries who plan an integration of datasets for the most accurate estimate of targeted sensitive attributes under a certain budget. To solve this problem, we introduce a graph-based formulation of the problem and predictive modeling methods to prioritize data resources for linkage. We perform an empirical analysis using real world voter registration data from two different U.S. states and show that the methods can be used efficiently to accurately estimate potentially sensitive information disclosure risks even under a non-trivial amount of noise.

Recently, using secure processors for trusted computing in cloud has attracted a lot of attention. Over the past few years, efficient and secure data analytic tools (e.g., map-reduce framework, machine learning models, and SQL querying) that can be executed over encrypted data using the trusted hardware have been developed. However, these prior efforts do not provide a simple, secure and high level language based framework that is suitable for enabling generic data analytics for non-security experts who do not have concepts such as "oblivious execution". In this paper, we thus provide such a framework that allows data scientists to perform the data analytic tasks with secure processors using a Python/Matlab-like high level language. Our framework automatically compiles programs written in our language to optimal execution code by managing issues such as optimal data block sizes for I/O, vectorized computations to simplify much of the data processing, and optimal ordering of operations for certain tasks. Furthermore, many language constructs such as if-statements are removed so that a non-expert user is less likely to create a piece of code that may reveal sensitive information while allowing oblivious data processing (i.e., hiding access patterns). Using these design choices, we provide guarantees for efficient and secure data analytics. We show that our framework can be used to run the existing big data benchmark queries over encrypted data using the Intel SGX efficiently. Our empirical results indicate that our proposed framework is orders of magnitude faster than the general oblivious execution alternatives.

The desire of moving from data to intelligence has become a trend that pushes the world we live in today fast forward. Machine learning and data mining techniques are being used as important tools to unlock the wealth of voluminous amounts of data owned by organizations. Despite the existing effort of explaining their underlying machinery in layman's terms, data mining models and their output remain as esoteric, discipline-based black boxes-viable only to experts with years of training and development experiences. As data mining techniques gain growing popularity in the real world, the ability to understand their intelligent decision-making artifacts has become increasingly important and critical, especially in areas such as criminal justice and law enforcement where transparency of decision-making is vital for ensuring fairness, justice, and equality. In this paper, we present a transparency model to help unmask the incomprehensible reasoning many data mining techniques are deservedly taking the blame for. Our transparency model substitutes a comprehensible, rule-based counterpart for the complex, black-box output of any data mining technique using a novel rule selection technique. The rule-based substitute explains the decision made for each instance with a tiny set of rules, resulting in a significant reduction in model complexity. Besides model simplicity and comprehensibility, we also assess the quality of our rule set by measuring its similarity to the output of the original data mining algorithm. Furthermore, we compute its accuracy on unseen test data as a complementary assessment criteria. We empirically demonstrate the effectiveness of our transparency model by experimenting on eight real datasets that deal with predicting important personal attributes ranging from credit worthiness to criminal recidivism. Our transparency model demonstrates a high degree of consistency with the original data mining algorithms in nearly all cases. We also compare our results to one of the state-of-the-art transparency models-LIME, and show that our transparency model outperforms LIME 84% of the time.

This paper focuses on cyber infrastructures composed on sensor networks and conventional host-based systems and applications. In such an infrastructure, assuring data trustworthiness is critical and requires the acquisition and recording of provenance information. This paper discusses research directions to be addressed towards the development of effective provenance management systems. Directions that are discussed include: services for provenance queries, provenance compression and encryption in sensor-based networks, and provenance interoperability and security in host-based systems.

Over the years social network data has been mined to predict individuals' traits such as intelligence and sexual orientation. While mining social network data can provide many beneficial services to the user such as personalized experiences, it can also harm the user when used in making critical decisions such as employment. In this work, we investigate the reliability of applying data mining techniques on social network data to predict various individual traits. In spite of the preliminary success of such data mining applications, in this paper, we demonstrate the vulnerabilities of existing state of the art social network data mining techniques when they are facing malicious attacks. Our results indicate that making critical decisions, such as employment or credit approval, based solely on social network data mining results is still premature at this stage. Specifically, we explore Facebook likes data for predicting the traits of a Facebook user, including their political views and sexual orientation. We perform several types of malicious attacks on the predictive models to measure and understand their potential vulnerabilities. We find that existing predictive models built on social network data can be easily manipulated and suggest some countermeasures to prevent some of the proposed attacks.

systems for providing data privacy, there is no general methodology for determining the extent to which these techniques, tools and systems reduce practical privacy risks. We need a comprehensive framework where the privacy and utility of multiple privacy-preserving techniques could be measured. This vision paper provides directions for designing such a framework.

Privacy concerns have increased in the last years due to the unprecedented scale of data collected regarding human activity. Differential privacy has emerged in the last decade as an important mechanism to ensure privacy by adding random noise with a specific distribution to the information being collected (e.g., adding noise to smart meters, and sensor readings). Differential privacy has been mainly used in private databases, but lately it has also been extended to consider applications like estimation, consensus algorithms, and control of dynamical systems.

Cyber-Physical Systems (CPS) have unique properties that can be exploited to design new privacy-enhancing technologies that minimize the negative impact to the utility of CPS. In this paper we show two examples of these properties.The first example looks at how differential privacy degrades CPS performance due to the large noise addition, and we then show how the inherent noise of CPS can be leveraged to reduce the additional noise added by differential privacy algorithms, and therefore, minimize the negative impact on the system utility and safety. In the second example we look at the ability to sample at sensor readings on demand, and how this flexibility can be used to design adaptive sensor sampling algorithms that hide sensitive information without the need to add noise.

This paper explores secure data processing in hybrid clouds wherein local computing capability is exploited alongside public cloud services to deliver an efficient and secure data management solution. Hybrid clouds offer numerous advantages including the ability to selectively outsource data and computations based on sensitivity/confidentiality. Data processing in hybrid clouds must address two interrelated challenges: (i) data distribution: how is data distributed across public and private machines, and (ii) distributed query processing: how are queries executed efficiently without leaking sensitive data to untrusted public machines. This paper addresses these challenges and incorporates the respective solutions into an add-on tool for a Hadoop, Spark, and Hive based cloud computing infrastructure. Our results show performance advantages in using our strategy as compared to other secure alternatives, even when the percentage of sensitive data is as high as 50%.

Protection of data privacy and prevention of unwarranted information disclosure is an enduring challenge in cloud computing when data analytics is performed on an untrusted third-party resource. Recent advances in trusted processor technology, such as Intel SGX, have rejuvenated the efforts of performing data analytics on a shared platform where data security and trustworthiness of computations are ensured by the hardware. However, a powerful adversary may still be able to infer private information in this setting from side channels such as cache access, CPU usage and other timing channels, thereby threatening data and user privacy. Though studies have proposed techniques to hide such information leaks through carefully designed data-independent access paths, such techniques can be prohibitively slow on models with large number of parameters, especially when employed in a real-time analytics application. In this paper, we introduce a defense strategy that can achieve higher computational efficiency with a small trade-off in privacy protection. In particular, we study a strategy that adds noise to traces of memory access observed by an adversary, with the use of dummy data instances. We quantitatively measure privacy guarantee, and empirically demonstrate the effectiveness and limitation of this randomization strategy, using classification and clustering algorithms. Our results show significant reduction in execution time overhead on real-world data sets, when compared to a defense strategy using only data-oblivious mechanisms.

Data mining techniques are playing an increasing role in making crucial decisions in our daily lives ranging from credit card approvals to employment decisions. Typically algorithms used to build decision models remain as a black-box to the end user. Therefore the process of decision making appears to be opaque. At the same time, increasing the transparency of a black-box decision making model allows us to discover hidden discrimination, and hold entities accountable. Although algorithmic transparency with respect to black box classifiers requires addressing many challenges, our main objective in this paper is to investigate whether a black-box classification model is biased against certain subgroups. Specifically, we study the indirect discrimination of hidden protected features. Protected features, such as race, gender, and religious beliefs, are those that are prohibited to be legally used for making decisions. Simply removing the protected features is not enough to eliminate discrimination because there could be strong correlations between protected features and non-protected features, such as race versus zip code. In this paper, we present two techniques to measure discrimination of a black-box model as a result of data bias or algorithmic weakness. Data bias is investigated further by introducing artificial bias to the dataset under consideration. Our experimental results demonstrate the effectiveness of our bias measures where bias comes from different sources.

As more and more cyber security incident data ranging from systems logs to vulnerability scan results are collected, manually analyzing these collected data to detect important cyber security events become impossible. Hence, data mining techniques are becoming an essential tool for real-world cyber security applications. For example, a report from Gartner [gartner12] claims that "Information security is becoming a big data analytics problem, where massive amounts of data will be correlated, analyzed and mined for meaningful patterns". Of course, data mining/analytics is a means to an end where the ultimate goal is to provide cyber security analysts with prioritized actionable insights derived from big data. This raises the question, can we directly apply existing techniques to cyber security applications? One of the most important differences between data mining for cyber security and many other data mining applications is the existence of malicious adversaries that continuously adapt their behavior to hide their actions and to make the data mining models ineffective. Unfortunately, traditional data mining techniques are insufficient to handle such adversarial problems directly. The adversaries adapt to the data miner's reactions, and data mining algorithms constructed based on a training dataset degrades quickly. To address these concerns, over the last couple of years new and novel data mining techniques which is more resilient to such adversarial behavior are being developed in machine learning and data mining community. We believe that lessons learned as a part of this research direction would be beneficial for cyber security researchers who are increasingly applying machine learning and data mining techniques in practice. To give an overview of recent developments in adversarial data mining, in this three hour long tutorial, we introduce the foundations, the techniques, and the applications of adversarial data mining to cyber security applications. We first introduce various approaches proposed in the past to defend against active adversaries, such as a minimax approach to minimize the worst case error through a zero-sum game. We then discuss a game theoretic framework to model the sequential actions of the adversary and the data miner, while both parties try to maximize their utilities. We also introduce a modified support vector machine method and a relevance vector machine method to defend against active adversaries. Intrusion detection and malware detection are two important application areas for adversarial data mining models that will be discussed in details during the tutorial. Finally, we discuss some practical guidelines on how to use adversarial data mining ideas in generic cyber security applications and how to leverage existing big data management tools for building data mining algorithms for cyber security.

IEEE Conference on Information Reuse and Integration, This paper describes a data driven approach to studying the science of cyber security (SoS). It argues that science is driven by data. It then describes issues and approaches towards the following three aspects: (i) Data Driven Science for Attack Detection and Mitigation, (ii) Foundations for Data Trustworthiness and Policy-based Sharing, and (iii) A Risk-based Approach to Security Metrics. We believe that the three aspects addressed in this paper will form the basis for studying the Science of Cyber Security.

Many data mining applications, such as spam filtering and intrusion detection, are faced with active adversaries. In all these applications, the future data sets and the training data set are no longer from the same population, due to the transformations employed by the adversaries. Hence a main assumption for the existing classification techniques no longer holds and initially successful classifiers degrade easily. This becomes a game between the adversary and the data miner: The adversary modifies its strategy to avoid being detected by the current classifier; the data miner then updates its classifier based on the new threats. In this paper, we investigate the possibility of an equilibrium in this seemingly never ending game, where neither party has an incentive to change. Modifying the classifier causes too many false positives with too little increase in true positives; changes by the adversary decrease the utility of the false negative items that are not detected. We develop a game theoretic framework where equilibrium behavior of adversarial classification applications can be analyzed, and provide solutions for finding an equilibrium point. A classifier's equilibrium performance indicates its eventual success or failure. The data miner could then select attributes based on their equilibrium performance, and construct an effective classifier. A case study on online lending data demonstrates how to apply the proposed game theoretic framework to a real application.

Exciting advances in big data analysis suggest that sharing personal information, such as health and location data, among multiple other parties could have significant societal benefits. However, privacy issues often hinder data sharing. Recently, differential privacy emerged as an important tool to preserve privacy while sharing privacy-sensitive data. The basic idea is simple. Differential privacy guarantees that results learned from shared data do not change much based on the inclusion or exclusion of any single person’s data. Despite the promise, existing differential privacy techniques addresses specific utility goals and/or query types (e.g., count queries), so it is not clear whether they can preserve utility for arbitrary types of queries. To better understand possible utility and privacy tradeoffs using differential privacy, we examined uses of human mobility data in a real-world competition. Participants were asked to come up with insightful ideas that leveraged a minimally protected published dataset. An obvious question is whether contest submissions could yield the same results if performed on a dataset protected by differential privacy? To answer this question, we studied synthetic dataset generation models for human mobility data using differential privacy. We discuss utility evaluation and the generality of the models extensively. Finally, we analyzed whether the proposed differential privacy models could be used in practice by examining contest submissions. Our results indicate that most of the competition submissions could be replicated using differentially private data with nearly the same utility and with privacy guarantees. Statistical comparisons with the original dataset demonstrate that differentially private synthetic versions of human mobility data can be widely applicable for data analysis.

Over the last few years, data storage in cloud based services has been very popular due to easy management and monetary advantages of cloud computing. Recent developments showed that such data could be leaked due to various attacks. To address some of these attacks, encrypting sensitive data before sending to cloud emerged as an important protection mechanism. If the data is encrypted with traditional techniques, selective retrieval of encrypted data becomes challenging. To address this challenge, efficient searchable encryption schemes have been developed over the years. Almost all of the existing searchable encryption schemes are developed for keyword searches and require running some code on the cloud servers. However, many of the existing cloud storage services (e.g., Dropbox (https://www.dropbox.com), Box (https://www.box.com/), Google Drive (http://drive.google.com/), etc.) only allow simple data object retrieval and do not provide computational support needed to realize most of the searchable encryption schemes.

Many data mining applications potentially operate in an adversarial environment where adversaries adapt their behavior to evade detection. Typically adversaries alter data under their control to cause a large divergence of distribution between training and test data. Existing state-of-the-art adversarial learning techniques try to address this problem in which there is only a single type of adversary. In practice, a learner often has to face multiple types of adversaries that may employ different attack tactics. In this paper, we tackle the challenges of multiple types of adversaries with a nested Stackelberg game framework. We demonstrate the effectiveness of our framework with extensive empirical results on both synthetic and real data sets. Our results demonstrate that the nested game framework offers more reliable defense against multiple types of attackers.