Biblio

In a secret sharing scheme a dealer shares a secret s among n parties such that an adversary corrupting up to t parties does not learn s, while any t+1 parties can efficiently recover s. Over a long period of time all parties may be corrupted thus violating the threshold, which is accounted for in Proactive Secret Sharing (PSS). PSS schemes periodically rerandomize (refresh) the shares of the secret and invalidate old ones. PSS retains confidentiality even when all parties are corrupted over the lifetime of the secret, but no more than t during a certain window of time, called the refresh period. Existing PSS schemes only guarantee secrecy in the presence of an honest majority with less than n2 total corruptions during a refresh period; an adversary corrupting a single additional party, even if only passively, obtains the secret. This work is the first feasibility result demonstrating PSS tolerating a dishonest majority, it introduces the first PSS scheme secure against t passive adversaries without recovery of lost shares, it can also recover from honest faulty parties losing their shares, and when tolerating e faults the scheme tolerates t passive corruptions. A non-robust version of the scheme can tolerate t active adversaries, and mixed adversaries that control a combination of passively and actively corrupted parties that are a majority, but where less than n/2-e of such corruptions are active. We achieve these high thresholds with O(n4) communication when sharing a single secret, and O(n3) communication when sharing multiple secrets in batches.

With the use of external cloud services such as Google Docs or Evernote in an enterprise setting, the loss of control over sensitive data becomes a major concern for organisations. It is typical for regular users to violate data disclosure policies accidentally, e.g. when sharing text between documents in browser tabs. Our goal is to help such users comply with data disclosure policies: we want to alert them about potentially unauthorised data disclosure from trusted to untrusted cloud services. This is particularly challenging when users can modify data in arbitrary ways, they employ multiple cloud services, and cloud services cannot be changed. To track the propagation of text data robustly across cloud services, we introduce imprecise data flow tracking, which identifies data flows implicitly by detecting and quantifying the similarity between text fragments. To reason about violations of data disclosure policies, we describe a new text disclosure model that, based on similarity, associates text fragments in web browsers with security tags and identifies unauthorised data flows to untrusted services. We demonstrate the applicability of imprecise data tracking through BrowserFlow, a browser-based middleware that alerts users when they expose potentially sensitive text to an untrusted cloud service. Our experiments show that BrowserFlow can robustly track data flows and manage security tags for documents with no noticeable performance impact.

Modern distributed key-value stores are offering superior performance, incremental scalability, and fine availability for data-intensive computing and cloud-based applications. Among those distributed data stores, the designs that ensure the confidentiality of sensitive data, however, have not been fully explored yet. In this paper, we focus on designing and implementing an encrypted, distributed, and searchable key-value store. It achieves strong protection on data privacy while preserving all the above prominent features of plaintext systems. We first design a secure data partition algorithm that distributes encrypted data evenly across a cluster of nodes. Based on this algorithm, we propose a secure transformation layer that supports multiple data models in a privacy-preserving way, and implement two basic APIs for the proposed encrypted key-value store. To enable secure search queries for secondary attributes of data, we leverage searchable symmetric encryption to design the encrypted secondary indexes which consider security, efficiency, and data locality simultaneously, and further enable secure query processing in parallel. For completeness, we present formal security analysis to demonstrate the strong security strength of the proposed designs. We implement the system prototype and deploy it to a cluster at Microsoft Azure. Comprehensive performance evaluation is conducted in terms of Put/Get throughput, Put/Get latency under different workloads, system scaling cost, and secure query performance. The comparison with Redis shows that our prototype can function in a practical manner.

Five core primitives belonging to most distributed systems are presented. These primitives apply well to systems with large amounts of data, scalability concerns, heterogeneity concerns, temporal concerns, and elements of unknown pedigree with possible nefarious intent. These primitives form the basic building blocks for a Network of 'Things' (NoT), including the Internet of Things (IoT). This talk discusses the underlying and foundational science of IoT. To our knowledge, the ideas and the manner in which the science underlying IoT is presented here is unique.
 

Five core primitives belonging to most distributed systems are presented. These primitives apply well to systems with large amounts of data, scalability concerns, heterogeneity concerns, temporal concerns, and elements of unknown pedigree with possible nefarious intent. These primitives form the basic building blocks for a Network of 'Things' (NoT), including the Internet of Things (IoT). This talk discusses the underlying and foundational science of IoT. To our knowledge, the ideas and the manner in which the science underlying IoT is presented here is unique.

We develop a novel model-based hardware-in-the-loop (HIL) framework for optimising energy consumption of embedded software controllers. Controller and plant models are specified as networks of parameterised timed input/output automata and translated into executable code. The controller is encoded into the target embedded hardware, which is connected to a power monitor and interacts with the simulation of the plant model. The framework then generates a power consumption model that maps controller transitions to distributions over power measurements, and is used to optimise the timing parameters of the controller, without compromising a given safety requirement. The novelty of our approach is that we measure the real power consumption of the controller and use thus obtained data for energy optimisation. We employ timed Petri nets as an intermediate representation of the executable specification, which facilitates efficient code generation and fast simulations. Our framework uniquely combines the advantages of rigorous specifications with accurate power measurements and methods for online model estimation, thus enabling automated design of correct and energy-efficient controllers.

In the Internet of Things (IoT), Internet-connected things provide an influx of data and resources that offer unlimited possibility for applications and services. Smart City IoT systems refer to the things that are distributed over wide physical areas covering a whole city. While the new breed of data and resources looks promising, building applications in such large scale IoT systems is a difficult task due to the distributed and dynamic natures of entities involved, such as sensing, actuating devices, people and computing resources. In this paper, we explore the process of developing Smart City IoT applications from a coordination-based perspective. We show that a distributed coordination model that oversees such a large group of distributed components is necessary in building Smart City IoT applications. In particular, we propose Adaptive Distributed Dataflow, a novel Dataflow-based programming model that focuses on coordinating city-scale distributed systems that are highly heterogeneous and dynamic.

In this research, we aim to suggest a method for designing trustworthy PRVAs (product recommendation virtual agents). We define an agent's trustworthiness as being operated by user emotion and knowledgeableness perceived by humans. Also, we suggest a user inner state transition model for increasing trust. To increase trust, we aim to cause user emotion to transition to positive by using emotional contagion and to cause user knowledgeableness perceived to become higher by increasing an agent's knowledge. We carried out two experiments to inspect this model. In experiment 1, the PRVAs recommended package tours and became highly knowledgeable in the latter half of ten recommendations. In experiment 2, the PRVAs recommended the same package tours and expressed a positive emotion in the latter half. As a result, participants' inner states transitioned as we expected, and it was proved that this model was valuable for PRVA recommendation.

Lightweight cryptography has been widely utilized in resource constrained embedded devices of Cyber-Physical System (CPS) terminals. The hostile and unattended environment in many scenarios make those endpoints easy to be attacked by hardware based techniques. As a resource-efficient countermeasure against Fault Attacks, parity Concurrent Error Detection (CED) is preferably integrated with security-critical algorithm in CPS terminals. The parity bit changes if an odd number of faults occur during the cipher execution. In this paper, we analyze the effectiveness of fault detection of a parity CED protected cipher (PRESENT) using laser fault injection. The experimental results show that the laser perturbation to encryption can easily flip an even number of data bits, where the faults cannot be detected by parity. Due to the similarity of different parity structures, our attack can bypass almost all parity protections in block ciphers. Some suggestions are given to enhance the security of parity implementations.

Android is the most commonly used mobile device operation system. The core of Android, the System Server (SS), is a multi-threaded process that provides most of the system services. Based on a new understanding of the security risks introduced by the callback mechanism in system services, we have discovered a general type of design flaw. A vulnerability detection tool has been designed and implemented based on static taint analysis. We applied the tool on all the 80 system services in the SS of Android 5.1.0. With its help, we have discovered six previously unknown vulnerabilities, which are further confirmed on Android 2.3.7-6.0.1. According to our analysis, about 97.3% of the entire 1.4 billion real-world Android devices are vulnerable. Our proof-of-concept attack proves that the vulnerabilities can enable a malicious app to freeze critical system functionalities or soft-reboot the system immediately. It is a neat type of denial-of-service at-tack. We also proved that the attacks can be conducted at mission critical moments to achieve meaningful goals, such as anti anti-virus, anti process-killer, hindering app updates or system patching. After being informed, Google confirmed our findings promptly. Several suggestions on how to use callbacks safely are also proposed to Google.

The ability to identify mobile apps in network traffic has significant implications in many domains, including traffic management, malware detection, and maintaining user privacy. App identification methods in the literature typically use deep packet inspection (DPI) and analyze HTTP headers to extract app fingerprints. However, these methods cannot be used if HTTP traffic is encrypted. We investigate whether Android apps can be identified from their launch-time network traffic using only TCP/IP headers. We first capture network traffic of 86,109 app launches by repeatedly running 1,595 apps on 4 distinct Android devices. We then use supervised learning methods used previously in the web page identification literature, to identify the apps that generated the traffic. We find that: (i) popular Android apps can be identified with 88% accuracy, by using the packet sizes of the first 64 packets they generate, when the learning methods are trained and tested on the data collected from same device; (ii) when the data from an unseen device (but similar operating system/vendor) is used for testing, the apps can be identified with 67% accuracy; (iii) the app identification accuracy does not drop significantly even if the training data are stale by several days, and (iv) the accuracy does drop quite significantly if the operating system/vendor is very different. We discuss the implications of our findings as well as open issues.

C programming language never performs automatic bounds checking in order to speed up execution. But bounds checking is absolutely necessary in any program. Because if a variable is out-of-bounds, some serious errors may occur during execution, such as endless loop or buffer overflows. When there are arrays used in a program, the index of an array must be within the boundary of the array. But programmers always miss the array bounds checking or do not perform a correct array bounds checking. In this paper, we perform static analysis based on taint analysis and data flow analysis to detect which arrays do not have correct array bounds checking in the program. And we implement an automatic static tool, Carraybound. And the experimental results show that Carraybound can work effectively and efficiently.

In this paper, we propose new types of cascading attacks against smart grid that use control command disaggregation and core smart grid services. Although there have been tremendous research efforts in injection attacks against the smart grid, to our knowledge most studies focus on false meter data injection, and false command and false feedback injection attacks have been scarcely investigated. In addition, control command disaggregation has not been addressed from a security point of view, in spite of the fact that it is becoming one of core concepts in the smart grid and hence analysing its security implications is crucial to the smart grid security. Our cascading attacks use false control command, false feedback or false meter data injection, and cascade the effects of such injections throughout the smart grid subsystems and components. Our analysis and evaluation results show that the proposed attacks can cause serious service disruptions in the smart grid. The evaluation has been performed on a widely used smart grid simulation platform.

Malicious Android applications pose serious threats to mobile security. They threaten the data confidentiality and system integrity on Android devices. Monitoring runtime activities serves as an important technique for analyzing dynamic app behaviors. We design a triggering relation model for dynamically analyzing network traffic on Android devices. Our model enables one to infer the dependency of outbound network requests from the device. We describe a new machine learning approach for discovering the dependency of network requests. These request-level dependence relations are used to detect stealthy malware activities. Malicious requests are identified due to the lack of dependency with legitimate triggers. Our prototype is evaluated on 14GB network traffic data and system logs collected from an Android tablet. Experimental results show that our solution achieves a high accuracy (99.1%) in detecting malicious requests sent from new malicious apps.

SQL injection is one of the major threats to the security of the web applications. Attackers try to gain unauthorized access to the database, which has vital and private information of the users. Many researchers have provided various techniques and practices to protect the web applications from attackers. There is a plethora of techniques available to perform SQL injection and usually not everyone is familiar with every attack. Hence, this kind of attack is still the most prevalent. In this paper, we have presented the types of SQL injections attacks and most dominant ways to prevent them.

This paper concerns the role of human errors in the field of Early Risk assessment in Software Project Management. Researchers have recently begun to focus on human errors in early risk assessment in large software projects; statistics show it to be major components of problems in software over 80% of economic losses are attributed to this problem. There has been comparatively diminutive experimental research on the role of human errors in this context, particularly evident at the organizational level, largely because of reluctance to share information and statistics on security issues in online software application. Grounded theory has been employed to investigate the main root of human errors in online security risks as a research methodology. An open-ended question was asked of 103 information security experts around the globe and the responses used to develop a list of human errors causes by open coding. The paper represents a contribution to our understanding of the causes of human errors in information security contexts. It is also one of the first information security research studies of the kind utilizing Strauss and Glaser's grounded theory approaches together, during data collection phases to achieve the required number of participants' responses and is a significant contribution to the field.

This paper concerns the role of human errors in the field of Early Risk assessment in Software Project Management. Researchers have recently begun to focus on human errors in early risk assessment in large software projects; statistics show it to be major components of problems in software over 80% of economic losses are attributed to this problem. There has been comparatively diminutive experimental research on the role of human errors in this context, particularly evident at the organizational level, largely because of reluctance to share information and statistics on security issues in online software application. Grounded theory has been employed to investigate the main root of human errors in online security risks as a research methodology. An open-ended question was asked of 103 information security experts around the globe and the responses used to develop a list of human errors causes by open coding. The paper represents a contribution to our understanding of the causes of human errors in information security contexts. It is also one of the first information security research studies of the kind utilizing Strauss and Glaser's grounded theory approaches together, during data collection phases to achieve the required number of participants' responses and is a significant contribution to the field.

Remote attestation is a crucial security service particularly relevant to increasingly popular IoT (and other embedded) devices. It allows a trusted party (verifier) to learn the state of a remote, and potentially malware-infected, device (prover). Most existing approaches are static in nature and only check whether benign software is initially loaded on the prover. However, they are vulnerable to runtime attacks that hijack the application's control or data flow, e.g., via return-oriented programming or data-oriented exploits. As a concrete step towards more comprehensive runtime remote attestation, we present the design and implementation of Control-FLow ATtestation (C-FLAT) that enables remote attestation of an application's control-flow path, without requiring the source code. We describe a full prototype implementation of C-FLAT on Raspberry Pi using its ARM TrustZone hardware security extensions. We evaluate C-FLAT's performance using a real-world embedded (cyber-physical) application, and demonstrate its efficacy against control-flow hijacking attacks.

Today’s Internet services are often expected to stay available and render high responsiveness even in the face of site crashes and network partitions. Theoretical results state that causal consistency is one of the strongest consistency guarantees that is possible under these requirements, and many practical systems provide causally consistent key-value stores. In this paper, we present a framework called Chapar for modular verification of causal consistency for replicated key-value store implementations and their client programs. Specifically, we formulate separate correctness conditions for key-value store implementations and for their clients. The interface between the two is a novel operational semantics for causal consistency. We have verified the causal consistency of two key-value store implementations from the literature using a novel proof technique. We have also implemented a simple automatic model checker for the correctness of client programs. The two independently verified results for the implementations and clients can be composed to conclude the correctness of any of the programs when executed with any of the implementations. We have developed and checked our framework in Coq, extracted it to OCaml, and built executable stores.

Fixing a non-deadlock concurrency bug is a difficult job that sometimes introduces additional bugs and requires a long time. To overcome this difficulty and efficiently perform fixing jobs, engineers should have broad knowledge of various fix patterns, and the ability to select the most proper one among those patterns based on quantitative data gathered from real-world bug databases. In this paper, we provide a real-world characteristic study on the fixes of non-deadlock concurrency bugs to help engineers responsible for program maintenance. In particular, we examine various fix patterns and the factors that influence the selection of those patterns with respect to the preexistence of locks and failure types. Our results will provide useful information for engineers who write bug patches, and researchers who study efficient testing and fixing techniques.

In the past decade, researchers have proposed various cloud storage integrity checking protocols to enable a cloud storage user to validate the integrity of the user's outsourced data. While the proposed solutions can in principle solve the cloud storage integrity checking problem, they are not sufficient for current cloud storage practices. In this position paper, we show the gaps between theoretical and practical cloud storage integrity checking solutions, through a categorization of existing solutions and an analysis of their underlying assumptions. To bridge the gap, we also call for practical cloud storage integrity checking solutions for three scenarios.

Early Internet of Things(IoT) applications have been build around cloud-centric architectures where information generated at the edge by the "things" in conveyed and processed in a cloud infrastructure. These architectures centralise processing and decision on the data-centre assuming sufficient connectivity, bandwidth and latency. As applications of the Internet of Things extend to industrial and more demanding consumer applications, the assumptions underlying cloud-centric architectures start to be violated as for several of these applications connectivity, bandwidth and latency to the data-centre are a challenge. Fog and Mist computing have emerged as forms of "Cloud Computing" closer to the "Edge" and to the "Things" that should alleviate the connectivity, bandwidth and latency challenges faced by Industrial and extremely demanding Consumer Internet of Things Applications. This keynote, will (1) introduce Cloud, Fog and Mist Computing architectures for the Internet of Things, (2) motivate their need and explain their applicability with real-world use cases, and (3) assess their technological maturity and highlight the areas that require further academic and industrial research.

As digital objects become increasingly important in people's lives, people may need to understand the provenance, or lineage and history, of an important digital object, to understand how it was produced. This is particularly important for objects created from large, multi-source collections of personal data. As the metadata describing provenance, Provenance Data, is commonly represented as a labelled directed acyclic graph, the challenge is to create effective interfaces onto such graphs so that people can understand the provenance of key digital objects. This unsolved problem is especially challenging for the case of novice and intermittent users and complex provenance graphs. We tackle this by creating an interface based on a clustering approach. This was designed to enable users to view provenance graphs, and to simplify complex graphs by combining several nodes. Our core contribution is the design of a prototype interface that supports clustering and its analytic evaluation in terms of desirable properties of visualisation interfaces.

Detecting “similar code” is useful for many software engineering tasks. Current tools can help detect code with statically similar syntactic and–or semantic features (code clones) and with dynamically similar functional input/output (simions). Unfortunately, some code fragments that behave similarly at the finer granularity of their execution traces may be ignored. In this paper, we propose the term “code relatives” to refer to code with similar execution behavior. We define code relatives and then present DyCLINK, our approach to detecting code relatives within and across codebases. DyCLINK records instruction-level traces from sample executions, organizes the traces into instruction-level dynamic dependence graphs, and employs our specialized subgraph matching algorithm to efficiently compare the executions of candidate code relatives. In our experiments, DyCLINK analyzed 422+ million prospective subgraph matches in only 43 minutes. We compared DyCLINK to one static code clone detector from the community and to our implementation of a dynamic simion detector. The results show that DyCLINK effectively detects code relatives with a reasonable analysis time.

Keys for symmetric cryptography are usually stored in RAM and therefore susceptible to various attacks, ranging from simple buffer overflows to leaks via cold boot, DMA or side channels. A common approach to mitigate such attacks is to move the keys to an external cryptographic token. For low-throughput applications like asymmetric signature generation, the performance of these tokens is sufficient. For symmetric, data-intensive use cases, like disk encryption on behalf of the host, the connecting interface to the token often is a serious bottleneck. In order to overcome this problem, we present CoKey, a novel concept for partially moving symmetric cryptography out of the host into a trusted detachable token. CoKey combines keys from both entities and securely encrypts initialization vectors on the token which are then used in the cryptographic operations on the host. This forces host and token to cooperate during the whole encryption and decryption process. Our concept strongly and efficiently binds encrypted data on the host to the specific token used for their encryption, while still allowing for fast operation. We implemented the concept using Linux hosts and the USB armory, a USB thumb drive sized ARM computer, as detachable crypto token. Our detailed performance evaluation shows that our prototype is easily fast enough even for data-intensive and performance-critical use cases like full disk encryption, thus effectively improving security for symmetric cryptography in a usable way.