Biblio

Found 2688 results

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2017-12-04
Farinholt, B., Rezaeirad, M., Pearce, P., Dharmdasani, H., Yin, H., Blond, S. L., McCoy, D., Levchenko, K..  2017.  To Catch a Ratter: Monitoring the Behavior of Amateur DarkComet RAT Operators in the Wild. 2017 IEEE Symposium on Security and Privacy (SP). :770–787.

Remote Access Trojans (RATs) give remote attackers interactive control over a compromised machine. Unlike large-scale malware such as botnets, a RAT is controlled individually by a human operator interacting with the compromised machine remotely. The versatility of RATs makes them attractive to actors of all levels of sophistication: they've been used for espionage, information theft, voyeurism and extortion. Despite their increasing use, there are still major gaps in our understanding of RATs and their operators, including motives, intentions, procedures, and weak points where defenses might be most effective. In this work we study the use of DarkComet, a popular commercial RAT. We collected 19,109 samples of DarkComet malware found in the wild, and in the course of two, several-week-long experiments, ran as many samples as possible in our honeypot environment. By monitoring a sample's behavior in our system, we are able to reconstruct the sequence of operator actions, giving us a unique view into operator behavior. We report on the results of 2,747 interactive sessions captured in the course of the experiment. During these sessions operators frequently attempted to interact with victims via remote desktop, to capture video, audio, and keystrokes, and to exfiltrate files and credentials. To our knowledge, we are the first large-scale systematic study of RAT use.

2018-10-26
Vorobiev, E. G., Petrenko, S. A., Kovaleva, I. V., Abrosimov, I. K..  2017.  Analysis of computer security incidents using fuzzy logic. 2017 XX IEEE International Conference on Soft Computing and Measurements (SCM). :369–371.

The work proposes and justifies a processing algorithm of computer security incidents based on the author's signatures of cyberattacks. Attention is also paid to the design pattern SOPKA based on the Russian ViPNet technology. Recommendations are made regarding the establishment of the corporate segment SOPKA, which meets the requirements of Presidential Decree of January 15, 2013 number 31c “On the establishment of the state system of detection, prevention and elimination of the consequences of cyber-attacks on information resources of the Russian Federation” and “Concept of the state system of detection, prevention and elimination of the consequences of cyber-attacks on information resources of the Russian Federation” approved by the President of the Russian Federation on December 12, 2014, No K 1274.

2018-02-14
Huang, K., Zhou, C., Tian, Y. C., Tu, W., Peng, Y..  2017.  Application of Bayesian network to data-driven cyber-security risk assessment in SCADA networks. 2017 27th International Telecommunication Networks and Applications Conference (ITNAC). :1–6.

Supervisory control and data acquisition (SCADA) systems are the key driver for critical infrastructures and industrial facilities. Cyber-attacks to SCADA networks may cause equipment damage or even fatalities. Identifying risks in SCADA networks is critical to ensuring the normal operation of these industrial systems. In this paper we propose a Bayesian network-based cyber-security risk assessment model to dynamically and quantitatively assess the security risk level in SCADA networks. The major distinction of our work is that the proposed risk assessment method can learn model parameters from historical data and then improve assessment accuracy by incrementally learning from online observations. Furthermore, our method is able to assess the risk caused by unknown attacks. The simulation results demonstrate that the proposed approach is effective for SCADA security risk assessment.

2018-03-05
Tselios, C., Politis, I., Kotsopoulos, S..  2017.  Enhancing SDN Security for IoT-Related Deployments through Blockchain. 2017 IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN). :303–308.

The majority of business activity of our integrated and connected world takes place in networks based on cloud computing infrastructure that cross national, geographic and jurisdictional boundaries. Such an efficient entity interconnection is made possible through an emerging networking paradigm, Software Defined Networking (SDN) that intends to vastly simplify policy enforcement and network reconfiguration in a dynamic manner. However, despite the obvious advantages this novel networking paradigm introduces, its increased attack surface compared to traditional networking deployments proved to be a thorny issue that creates skepticism when safety-critical applications are considered. Especially when SDN is used to support Internet-of-Things (IoT)-related networking elements, additional security concerns rise, due to the elevated vulnerability of such deployments to specific types of attacks and the necessity of inter-cloud communication any IoT application would require. The overall number of connected nodes makes the efficient monitoring of all entities a real challenge, that must be tackled to prevent system degradation and service outage. This position paper provides an overview of common security issues of SDN when linked to IoT clouds, describes the design principals of the recently introduced Blockchain paradigm and advocates the reasons that render Blockchain as a significant security factor for solutions where SDN and IoT are involved.

Tselios, C., Politis, I., Kotsopoulos, S..  2017.  Enhancing SDN Security for IoT-Related Deployments through Blockchain. 2017 IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN). :303–308.

The majority of business activity of our integrated and connected world takes place in networks based on cloud computing infrastructure that cross national, geographic and jurisdictional boundaries. Such an efficient entity interconnection is made possible through an emerging networking paradigm, Software Defined Networking (SDN) that intends to vastly simplify policy enforcement and network reconfiguration in a dynamic manner. However, despite the obvious advantages this novel networking paradigm introduces, its increased attack surface compared to traditional networking deployments proved to be a thorny issue that creates skepticism when safety-critical applications are considered. Especially when SDN is used to support Internet-of-Things (IoT)-related networking elements, additional security concerns rise, due to the elevated vulnerability of such deployments to specific types of attacks and the necessity of inter-cloud communication any IoT application would require. The overall number of connected nodes makes the efficient monitoring of all entities a real challenge, that must be tackled to prevent system degradation and service outage. This position paper provides an overview of common security issues of SDN when linked to IoT clouds, describes the design principals of the recently introduced Blockchain paradigm and advocates the reasons that render Blockchain as a significant security factor for solutions where SDN and IoT are involved.

2018-03-19
Ditzler, G., Prater, A..  2017.  Fine Tuning Lasso in an Adversarial Environment against Gradient Attacks. 2017 IEEE Symposium Series on Computational Intelligence (SSCI). :1–7.

Machine learning and data mining algorithms typically assume that the training and testing data are sampled from the same fixed probability distribution; however, this violation is often violated in practice. The field of domain adaptation addresses the situation where this assumption of a fixed probability between the two domains is violated; however, the difference between the two domains (training/source and testing/target) may not be known a priori. There has been a recent thrust in addressing the problem of learning in the presence of an adversary, which we formulate as a problem of domain adaption to build a more robust classifier. This is because the overall security of classifiers and their preprocessing stages have been called into question with the recent findings of adversaries in a learning setting. Adversarial training (and testing) data pose a serious threat to scenarios where an attacker has the opportunity to ``poison'' the training or ``evade'' on the testing data set(s) in order to achieve something that is not in the best interest of the classifier. Recent work has begun to show the impact of adversarial data on several classifiers; however, the impact of the adversary on aspects related to preprocessing of data (i.e., dimensionality reduction or feature selection) has widely been ignored in the revamp of adversarial learning research. Furthermore, variable selection, which is a vital component to any data analysis, has been shown to be particularly susceptible under an attacker that has knowledge of the task. In this work, we explore avenues for learning resilient classification models in the adversarial learning setting by considering the effects of adversarial data and how to mitigate its effects through optimization. Our model forms a single convex optimization problem that uses the labeled training data from the source domain and known- weaknesses of the model for an adversarial component. We benchmark the proposed approach on synthetic data and show the trade-off between classification accuracy and skew-insensitive statistics.

2018-05-30
Pal, S., Poornachandran, P., Krishnan, M. R., Au, P. S., Sasikala, P..  2017.  Malsign: Threat Analysis of Signed and Implicitly Trusted Malicious Code. 2017 International Conference on Public Key Infrastructure and Its Applications (PKIA). :23–27.

Code signing which at present is the only methodology of trusting a code that is distributed to others. It heavily relies on the security of the software providers private key. Attackers employ targeted attacks on the code signing infrastructure for stealing the signing keys which are used later for distributing malware in disguise of genuine software. Differentiating a malware from a benign software becomes extremely difficult once it gets signed by a trusted software providers private key as the operating systems implicitly trusts this signed code. In this paper, we analyze the growing menace of signed malware by examining several real world incidents and present a threat model for the current code signing infrastructure. We also propose a novel solution that prevents this issue of malicious code signing by requiring additional verification of the executable. We also present the serious threat it poses and it consequences. To our knowledge this is the first time this specific issue of Malicious code signing has been thoroughly studied and an implementable solution is proposed.

2018-06-20
Petersen, E., To, M. A., Maag, S..  2017.  A novel online CEP learning engine for MANET IDS. 2017 IEEE 9th Latin-American Conference on Communications (LATINCOM). :1–6.

In recent years the use of wireless ad hoc networks has seen an increase of applications. A big part of the research has focused on Mobile Ad Hoc Networks (MAnETs), due to its implementations in vehicular networks, battlefield communications, among others. These peer-to-peer networks usually test novel communications protocols, but leave out the network security part. A wide range of attacks can happen as in wired networks, some of them being more damaging in MANETs. Because of the characteristics of these networks, conventional methods for detection of attack traffic are ineffective. Intrusion Detection Systems (IDSs) are constructed on various detection techniques, but one of the most important is anomaly detection. IDSs based only in past attacks signatures are less effective, even more if these IDSs are centralized. Our work focuses on adding a novel Machine Learning technique to the detection engine, which recognizes attack traffic in an online way (not to store and analyze after), re-writing IDS rules on the fly. Experiments were done using the Dockemu emulation tool with Linux Containers, IPv6 and OLSR as routing protocol, leading to promising results.

2018-05-27
Jun Han, Shijia Pan, Manal Kumar Sinha, Hae Young Noh, Pei Zhang, Patrick Tague.  2017.  SenseTribute: Smart Home Occupant Identification via Fusion Across On-Object Sensing Devices. 4th ACM International Conference on Systems for Energy-Efficient Built Environments (BuildSys).

to appear

2017-12-20
Nguyen, C. T., Hoang, T. T., Phan, V. X..  2017.  A simple method for anonymous tag cardinality estimation in RFID systems with false detection. 2017 4th NAFOSTED Conference on Information and Computer Science. :101–104.

This work investigates the anonymous tag cardinality estimation problem in radio frequency identification systems with frame slotted aloha-based protocol. Each tag, instead of sending its identity upon receiving the reader's request, randomly responds by only one bit in one of the time slots of the frame due to privacy and security. As a result, each slot with no response is observed as in an empty state, while the others are non-empty. Those information can be used for the tag cardinality estimation. Nevertheless, under effects of fading and noise, time slots with tags' response might be observed as empty, while those with no response might be detected as non-empty, which is known as a false detection phenomenon. The performance of conventional estimation methods is, thus, degraded because of inaccurate observations. In order to cope with this issue, we propose a new estimation algorithm using expectation-maximization method. Both the tag cardinality and a probability of false detection are iteratively estimated to maximize a likelihood function. Computer simulations will be provided to show the merit of the proposed method.

2020-07-20
Masood, Raziqa, Pandey, Nitin, Rana, Q. P..  2017.  An approach of dredging the interconnected nodes and repudiating attacks in cloud network. 2017 4th IEEE Uttar Pradesh Section International Conference on Electrical, Computer and Electronics (UPCON). :49–53.
In cloud computing environment, there are malignant nodes which create a huge problem to transfer data in communication. As there are so many models to prevent the data over the network, here we try to prevent or make secure to the network by avoiding mallicious nodes in between the communication. So the probabiliostic approach what we use here is a coherent tool to supervise the security challenges in the cloud environment. The matter of security for cloud computing is a superficial quality of service from cloud service providers. Even, cloud computing dealing everyday with new challenges, which is in process to well investigate. This research work draws the light on aspect regarding with the cloud data transmission and security by identifying the malignanat nodes in between the communication. Cloud computing network shared the common pool of resources like hardware, framework, platforms and security mechanisms. therefore Cloud Computing cache the information and deliver the secure transaction of data, so privacy and security has become the bone of contention which hampers the process to execute safely. To ensure the security of data in cloud environment, we proposed a method by implementing white box cryptography on RSA algorithm and then we work on the network, and find the malignant nodes which hampering the communication by hitting each other in the network. Several existing security models already have been deployed with security attacks. A probabilistic authentication and authorization approach is introduced to overcome this attack easily. It observes corrupted nodes before hitting with maximum probability. here we use a command table to conquer the malignant nodes. then we do the comparative study and it shows the probabilistic authentication and authorization protocol gives the performance much better than the old ones.
2018-04-02
Kolamunna, H., Chauhan, J., Hu, Y., Thilakarathna, K., Perino, D., Makaroff, D., Seneviratne, A..  2017.  Are Wearables Ready for HTTPS? On the Potential of Direct Secure Communication on Wearables 2017 IEEE 42nd Conference on Local Computer Networks (LCN). :321–329.

The majority of available wearable computing devices require communication with Internet servers for data analysis and storage, and rely on a paired smartphone to enable secure communication. However, many wearables are equipped with WiFi network interfaces, enabling direct communication with the Internet. Secure communication protocols could then run on these wearables themselves, yet it is not clear if they can be efficiently supported.,,,,In this paper, we show that wearables are ready for direct and secure Internet communication by means of experiments with both controlled local web servers and Internet servers. We observe that the overall energy consumption and communication delay can be reduced with direct Internet connection via WiFi from wearables compared to using smartphones as relays via Bluetooth. We also show that the additional HTTPS cost caused by TLS handshake and encryption is closely related to the number of parallel connections, and has the same relative impact on wearables and smartphones.

2018-02-21
Purnomo, M. F. E., Kitagawa, A..  2017.  Developing basic configuration of triangle array antenna for circularly polarized-Synthetic Aperture Radar sensor application. 2017 International Conference on Radar, Antenna, Microwave, Electronics, and Telecommunications (ICRAMET). :112–117.

The development of radar technology, Synthetic Aperture Radar (SAR) and Unmanned Aerial Vehicle (UAV) requires the communication facilities and infrastructures that have variety of platforms and high quality of image. In this paper, we obtain the basic configuration of triangle array antenna using corporate feeding-line for Circularly Polarized- Synthetic Aperture Radar (CP-SAR) sensor embedded on small UAV or drone airspace with compact, small, and simple configuration. The Method of Moments (MoM) is chosen in the numerical analysis for fast calculation of the unknown current on the patch antenna. The developing of triangle array antenna is consist of four patches of simple equilateral triangle patch with adding truncated corner of each patch and resonant frequency at f = 1.25 GHz. Proximity couple, perturbation segment, single feeding method are applied to generate the circular polarization wave from radiating patch. The corporate feeding-line design is implemented by combining some T-junctions to distribute the current from input port to radiating patch and to reach 2×2 patches. The performance results of this antenna, especially for gain and axial ratio (Ar) at the resonant frequency are 11.02 dBic and 2.47 dB, respectively. Furthermore, the two-beams appeared at boresight in elevation plane have similar values each other i.e. for average beamwidth of 10 dBic-gain and the 3 dB-Ar are about 20° and 70°, respectively.

2018-02-06
Shi, Y., Piao, C., Zheng, L..  2017.  Differential-Privacy-Based Correlation Analysis in Railway Freight Service Applications. 2017 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery (CyberC). :35–39.

With the development of modern logistics industry railway freight enterprises as the main traditional logistics enterprises, the service mode is facing many problems. In the era of big data, for railway freight enterprises, coordinated development and sharing of information resources have become the requirements of the times, while how to protect the privacy of citizens has become one of the focus issues of the public. To prevent the disclosure or abuse of the citizens' privacy information, the citizens' privacy needs to be preserved in the process of information opening and sharing. However, most of the existing privacy preserving models cannot to be used to resist attacks with continuously growing background knowledge. This paper presents the method of applying differential privacy to protect associated data, which can be shared in railway freight service association information. First, the original service data need to slice by optimal shard length, then differential method and apriori algorithm is used to add Laplace noise in the Candidate sets. Thus the citizen's privacy information can be protected even if the attacker gets strong background knowledge. Last, sharing associated data to railway information resource partners. The steps and usefulness of the discussed privacy preservation method is illustrated by an example.

2018-01-10
Breuer, P. T., Bowen, J. P., Palomar, E., Liu, Z..  2017.  Encrypted computing: Speed, security and provable obfuscation against insiders. 2017 International Carnahan Conference on Security Technology (ICCST). :1–6.

Over the past few years we have articulated theory that describes ‘encrypted computing’, in which data remains in encrypted form while being worked on inside a processor, by virtue of a modified arithmetic. The last two years have seen research and development on a standards-compliant processor that shows that near-conventional speeds are attainable via this approach. Benchmark performance with the US AES-128 flagship encryption and a 1GHz clock is now equivalent to a 433MHz classic Pentium, and most block encryptions fit in AES's place. This summary article details how user data is protected by a system based on the processor from being read or interfered with by the computer operator, for those computing paradigms that entail trust in data-oriented computation in remote locations where it may be accessible to powerful and dishonest insiders. We combine: (i) the processor that runs encrypted; (ii) a slightly modified conventional machine code instruction set architecture with which security is achievable; (iii) an ‘obfuscating’ compiler that takes advantage of its possibilities, forming a three-point system that provably provides cryptographic "semantic security" for user data against the operator and system insiders.

2018-02-14
Zhao, J., Shetty, S., Pan, J. W..  2017.  Feature-based transfer learning for network security. MILCOM 2017 - 2017 IEEE Military Communications Conference (MILCOM). :17–22.

New and unseen network attacks pose a great threat to the signature-based detection systems. Consequently, machine learning-based approaches are designed to detect attacks, which rely on features extracted from network data. The problem is caused by different distribution of features in the training and testing datasets, which affects the performance of the learned models. Moreover, generating labeled datasets is very time-consuming and expensive, which undercuts the effectiveness of supervised learning approaches. In this paper, we propose using transfer learning to detect previously unseen attacks. The main idea is to learn the optimized representation to be invariant to the changes of attack behaviors from labeled training sets and non-labeled testing sets, which contain different types of attacks and feed the representation to a supervised classifier. To the best of our knowledge, this is the first effort to use a feature-based transfer learning technique to detect unseen variants of network attacks. Furthermore, this technique can be used with any common base classifier. We evaluated the technique on publicly available datasets, and the results demonstrate the effectiveness of transfer learning to detect new network attacks.

2018-06-07
Zenger, C. T., Pietersz, M., Rex, A., Brauer, J., Dressler, F. P., Baiker, C., Theis, D., Paar, C..  2017.  Implementing a real-time capable WPLS testbed for independent performance and security analyses. 2017 51st Asilomar Conference on Signals, Systems, and Computers. :9–13.

As demonstrated recently, Wireless Physical Layer Security (WPLS) has the potential to offer substantial advantages for key management for small resource-constrained and, therefore, low-cost IoT-devices, e.g., the widely applied 8-bit MCU 8051. In this paper, we present a WPLS testbed implementation for independent performance and security evaluations. The testbed is based on off-the-shelf hardware and utilizes the IEEE 802.15.4 communication standard for key extraction and secret key rate estimation in real-time. The testbed can include generically multiple transceivers to simulate legitimate parties or eavesdropper. We believe with the testbed we provide a first step to make experimental-based WPLS research results comparable. As an example, we present evaluation results of several test cases we performed, while for further information we refer to https://pls.rub.de.

2018-11-19
Sun, K., Esnaola, I., Perlaza, S. M., Poor, H. V..  2017.  Information-Theoretic Attacks in the Smart Grid. 2017 IEEE International Conference on Smart Grid Communications (SmartGridComm). :455–460.

Gaussian random attacks that jointly minimize the amount of information obtained by the operator from the grid and the probability of attack detection are presented. The construction of the attack is posed as an optimization problem with a utility function that captures two effects: firstly, minimizing the mutual information between the measurements and the state variables; secondly, minimizing the probability of attack detection via the Kullback-Leibler (KL) divergence between the distribution of the measurements with an attack and the distribution of the measurements without an attack. Additionally, a lower bound on the utility function achieved by the attacks constructed with imperfect knowledge of the second order statistics of the state variables is obtained. The performance of the attack construction using the sample covariance matrix of the state variables is numerically evaluated. The above results are tested in the IEEE 30-Bus test system.

2018-01-16
Ahmed, M. E., Kim, H., Park, M..  2017.  Mitigating DNS query-based DDoS attacks with machine learning on software-defined networking. MILCOM 2017 - 2017 IEEE Military Communications Conference (MILCOM). :11–16.

Securing Internet of Things is a challenge because of its multiple points of vulnerability. In particular, Distributed Denial of Service (DDoS) attacks on IoT devices pose a major security challenge to be addressed. In this paper, we propose a DNS query-based DDoS attack mitigation system using Software-Defined Networking (SDN) to block the network traffic for DDoS attacks. With some features provided by SDN, we can analyze traffic patterns and filter suspicious network flows out. To show the feasibility of the proposed system, we particularly implemented a prototype with Dirichlet process mixture model to distinguish benign traffic from malicious traffic and conducted experiments with the dataset collected from real network traces. We demonstrate the effectiveness of the proposed method by both simulations and experiment data obtained from the real network traffic traces.

2021-05-25
Raj, Rajendra K., Ekstrom, Joseph J., Impagliazzo, John, Lingafelt, Steven, Parrish, Allen, Reif, Harry, Sobiesk, Ed.  2017.  Perspectives on the future of cybersecurity education. 2017 IEEE Frontiers in Education Conference (FIE). :1—2.
As the worldwide demand for cybersecurity-trained professionals continues to grow, the need to understand and define what cybersecurity education really means at the college or university level. Given the relative infancy of these efforts to define undergraduate cybersecurity programs, the panelists will present different perspectives on how such programs can be structured. They will then engage with the audience to explore additional viewpoints on cybersecurity, and work toward a shared understanding of undergraduate cybersecurity programs.
2017-12-20
Zhang, S., Peng, J., Huang, K., Xu, X., Zhong, Z..  2017.  Physical layer security in IoT: A spatial-temporal perspective. 2017 9th International Conference on Wireless Communications and Signal Processing (WCSP). :1–6.
Delay and security are both highly concerned in the Internet of Things (IoT). In this paper, we set up a secure analytical framework for IoT networks to characterize the network delay performance and secrecy performance. Firstly, stochastic geometry and queueing theory are adopted to model the location of IoT devices and the temporal arrival of packets. Based on this model, a low-complexity secure on-off scheme is proposed to improve the network performance. Then, the delay performance and secrecy performance are evaluated in terms of packet delay and packet secrecy outage probability. It is demonstrated that the intensity of IoT devices arouse a tradeoff between the delay and security and the secure on-off scheme can improve the network delay performance and secrecy performance. Moreover, secrecy transmission rate is adopted to reflect the delay-security tradeoff. The analytical and simulation results show the effects of intensity of IoT devices and secure on-off scheme on the network delay performance and secrecy performance.
2018-05-30
Howard, M., Pfeffer, A., Dalai, M., Reposa, M..  2017.  Predicting Signatures of Future Malware Variants. 2017 12th International Conference on Malicious and Unwanted Software (MALWARE). :126–132.
One of the challenges of malware defense is that the attacker has the advantage over the defender. In many cases, an attack is successful and causes damage before the defender can even begin to prepare a defense. The ability to anticipate attacks and prepare defenses before they occur would be a significant scientific and technological development with practical applications in cybersecurity. In this paper, we present a method to augment machine learning-based malware detection systems by predicting signatures of future malware variants and injecting these variants into the defensive system as a vaccine. Our method uses deep learning to learn patterns of malware evolution from family histories. These evolution patterns are then used to predict future family developments. Our experiments show that a detection system augmented with these future malware signatures is able to detect future malware variants that could not be detected by the detection system alone. In particular, it detected 11 new malware variants without increasing false positives, while providing up to 5 months of lead time between prediction and attack.
2018-01-10
Zhang, Jun, Cormode, Graham, Procopiuc, Cecilia M., Srivastava, Divesh, Xiao, Xiaokui.  2017.  PrivBayes: Private Data Release via Bayesian Networks. ACM Trans. Database Syst.. 42:25:1–25:41.
Privacy-preserving data publishing is an important problem that has been the focus of extensive study. The state-of-the-art solution for this problem is differential privacy, which offers a strong degree of privacy protection without making restrictive assumptions about the adversary. Existing techniques using differential privacy, however, cannot effectively handle the publication of high-dimensional data. In particular, when the input dataset contains a large number of attributes, existing methods require injecting a prohibitive amount of noise compared to the signal in the data, which renders the published data next to useless. To address the deficiency of the existing methods, this paper presents PrivBayes, a differentially private method for releasing high-dimensional data. Given a dataset D, PrivBayes first constructs a Bayesian network N, which (i) provides a succinct model of the correlations among the attributes in D and (ii) allows us to approximate the distribution of data in D using a set P of low-dimensional marginals of D. After that, PrivBayes injects noise into each marginal in P to ensure differential privacy and then uses the noisy marginals and the Bayesian network to construct an approximation of the data distribution in D. Finally, PrivBayes samples tuples from the approximate distribution to construct a synthetic dataset, and then releases the synthetic data. Intuitively, PrivBayes circumvents the curse of dimensionality, as it injects noise into the low-dimensional marginals in P instead of the high-dimensional dataset D. Private construction of Bayesian networks turns out to be significantly challenging, and we introduce a novel approach that uses a surrogate function for mutual information to build the model more accurately. We experimentally evaluate PrivBayes on real data and demonstrate that it significantly outperforms existing solutions in terms of accuracy.
2017-12-28
Panetta, J., Filho, P. R. P. S., Laranjeira, L. A. F., Teixeira, C. A..  2017.  Scalability of CPU and GPU Solutions of the Prime Elliptic Curve Discrete Logarithm Problem. 2017 29th International Symposium on Computer Architecture and High Performance Computing (SBAC-PAD). :33–40.

Elliptic curve asymmetric cryptography has achieved increased popularity due to its capability of providing comparable levels of security as other existing cryptographic systems while requiring less computational work. Pollard Rho and Parallel Collision Search, the fastest known sequential and parallel algorithms for breaking this cryptographic system, have been successfully applied over time to break ever-increasing bit-length system instances using implementations heavily optimized for the available hardware. This work presents portable, general implementations of a Parallel Collision Search based solution for prime elliptic curve asymmetric cryptographic systems that use publicly available big integer libraries and make no assumption on prime curve properties. It investigates which bit-length keys can be broken in reasonable time by a user that has access to a state of the art, public HPC equipment with CPUs and GPUs. The final implementation breaks a 79-bit system in about two hours using 80 GPUs and 94-bits system in about 15 hours using 256 GPUs. Extensive experimentation investigates scalability of CPU, GPU and CPU+GPU runs. The discussed results indicate that speed-up is not a good metric for parallel scalability. This paper proposes and evaluates a new metric that is better suited for this task.

2018-02-15
Wang, C., Lizana, F. R., Li, Z., Peterchev, A. V., Goetz, S. M..  2017.  Submodule short-circuit fault diagnosis based on wavelet transform and support vector machines for modular multilevel converter with series and parallel connectivity. IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society. :3239–3244.

The modular multilevel converter with series and parallel connectivity was shown to provide advantages in several industrial applications. Its reliability largely depends on the absence of failures in the power semiconductors. We propose and analyze a fault-diagnosis technique to identify shorted switches based on features generated through wavelet transform of the converter output and subsequent classification in support vector machines. The multi-class support vector machine is trained with multiple recordings of the output of each fault condition as well as the converter under normal operation. Simulation results reveal that the proposed method has high classification latency and high robustness. Except for the monitoring of the output, which is required for the converter control in any case, this method does not require additional module sensors.