Visible to the public Biblio

Found 1171 results

Filters: First Letter Of Title is P  [Clear All Filters]
2018-01-23
Zhu, Ruiyu, Huang, Yan, Cassel, Darion.  2017.  Pool: Scalable On-Demand Secure Computation Service Against Malicious Adversaries. Proceedings of the 2017 ACM SIGSAC Conference on Computer and Communications Security. :245–257.

This paper considers the problem of running a long-term on-demand service for executing actively-secure computations. We examined state-of-the-art tools and implementations for actively-secure computation and identified a set of key features indispensable to offer meaningful service like this. Since no satisfactory tools exist for the purpose, we developed Pool, a new tool for building and executing actively-secure computation protocols at extreme scales with nearly zero offline delay. With Pool, we are able to obliviously execute, for the first time, reactive computations like ORAM in the malicious threat model. Many technical benefits of Pool can be attributed to the concept of pool-based cut-and-choose. We show with experiments that this idea has significantly improved the scalability and usability of JIMU, a state-of-the-art LEGO protocol.

Moghaddam, F. F., Wieder, P., Yahyapour, R..  2017.  A policy-based identity management schema for managing accesses in clouds. 2017 8th International Conference on the Network of the Future (NOF). :91–98.

Security challenges are the most important obstacles for the advancement of IT-based on-demand services and cloud computing as an emerging technology. Lack of coincidence in identity management models based on defined policies and various security levels in different cloud servers is one of the most challenging issues in clouds. In this paper, a policy- based user authentication model has been presented to provide a reliable and scalable identity management and to map cloud users' access requests with defined polices of cloud servers. In the proposed schema several components are provided to define access policies by cloud servers, to apply policies based on a structural and reliable ontology, to manage user identities and to semantically map access requests by cloud users with defined polices. Finally, the reliability and efficiency of this policy-based authentication schema have been evaluated by scientific performance, security and competitive analysis. Overall, the results show that this model has met defined demands of the research to enhance the reliability and efficiency of identity management in cloud computing environments.

Yasin, Muhammad, Sengupta, Abhrajit, Nabeel, Mohammed Thari, Ashraf, Mohammed, Rajendran, Jeyavijayan(JV), Sinanoglu, Ozgur.  2017.  Provably-Secure Logic Locking: From Theory To Practice. Proceedings of the 2017 ACM SIGSAC Conference on Computer and Communications Security. :1601–1618.

Logic locking has been conceived as a promising proactive defense strategy against intellectual property (IP) piracy, counterfeiting, hardware Trojans, reverse engineering, and overbuilding attacks. Yet, various attacks that use a working chip as an oracle have been launched on logic locking to successfully retrieve its secret key, undermining the defense of all existing locking techniques. In this paper, we propose stripped-functionality logic locking (SFLL), which strips some of the functionality of the design and hides it in the form of a secret key(s), thereby rendering on-chip implementation functionally different from the original one. When loaded onto an on-chip memory, the secret keys restore the original functionality of the design. Through security-aware synthesis that creates a controllable mismatch between the reverse-engineered netlist and original design, SFLL provides a quantifiable and provable resilience trade-off between all known and anticipated attacks. We demonstrate the application of SFLL to large designs (textgreater100K gates) using a computer-aided design (CAD) framework that ensures attaining the desired security level at minimal implementation cost, 8%, 5%, and 0.5% for area, power, and delay, respectively. In addition to theoretical proofs and simulation confirmation of SFLL's security, we also report results from the silicon implementation of SFLL on an ARM Cortex-M0 microprocessor in 65nm technology.

Abtioglu, E., Yeniçeri, R., Gövem, B., Göncü, E., Yalçin, M. E., Saldamli, G..  2017.  Partially Reconfigurable IP Protection System with Ring Oscillator Based Physically Unclonable Functions. 2017 New Generation of CAS (NGCAS). :65–68.

The size of counterfeiting activities is increasing day by day. These activities are encountered especially in electronics market. In this paper, a countermeasure against counterfeiting on intellectual properties (IP) on Field-Programmable Gate Arrays (FPGA) is proposed. FPGA vendors provide bitstream ciphering as an IP security solution such as battery-backed or non-volatile FPGAs. However, these solutions are secure as long as they can keep decryption key away from third parties. Key storage and key transfer over unsecure channels expose risks for these solutions. In this work, physical unclonable functions (PUFs) have been used for key generation. Generating a key from a circuit in the device solves key transfer problem. Proposed system goes through different phases when it operates. Therefore, partial reconfiguration feature of FPGAs is essential for feasibility of proposed system.

Groß, Tobias, Müller, Tilo.  2017.  Protecting JavaScript Apps from Code Analysis. Proceedings of the 4th Workshop on Security in Highly Connected IT Systems. :1–6.
Apps written in JavaScript are an easy target for reverse engineering attacks, e.g. to steal the intellectual property or to create a clone of an app. Unprotected JavaScript apps even contain high level information such as developer comments, if those were not explicitly stripped. This fact becomes more and more important with the increasing popularity of JavaScript as language of choice for both web development and hybrid mobile apps. In this paper, we present a novel JavaScript obfuscator based on the Google Closure Compiler, which transforms readable JavaScript source code into a representation much harder to analyze for adversaries. We evaluate this obfuscator regarding its performance impact and its semantics-preserving property.
Huber, Manuel, Horsch, Julian, Wessel, Sascha.  2017.  Protecting Suspended Devices from Memory Attacks. Proceedings of the 10th European Workshop on Systems Security. :10:1–10:6.

Today's computing devices keep considerable amounts of sensitive data unencrypted in RAM. When stolen, lost or simply unattended, attackers are capable of accessing the data in RAM with ease. Valuable and possibly classified data falling into the wrongs hands can lead to severe consequences, for instance when disclosed or reused to log in to accounts or to make transactions. We present a lightweight and hardware-independent mechanism to protect confidential data on suspended Linux devices against physical attackers. Our mechanism rapidly encrypts the contents of RAM during suspension and thereby prevents attackers from retrieving confidential data from the device. Existing systems can easily be extended with our mechanism while fully preserving the usability for end users.

Keni, H., Earle, M., Min, M..  2017.  Product authentication using hash chains and printed QR codes. 2017 14th IEEE Annual Consumer Communications Networking Conference (CCNC). :319–324.

In this paper, we explore the usage of printed tags to authenticate products. Printed tags are a cheap alternative to RFID and other tag based systems and do not require specialized equipment. Due to the simplistic nature of such printed codes, many security issues like tag impersonation, server impersonation, reader impersonation, replay attacks and denial of service present in RFID based solutions need to be handled differently. We propose a cost-efficient scheme based on static tag based hash chains to address these security threats. We analyze the security characteristics of this scheme and compare it to other product authentication schemes that use RFID tags. Finally, we show that our proposed statically printed QR codes can be at least as secure as RFID tags.

Wang, B., Song, W., Lou, W., Hou, Y. T..  2017.  Privacy-preserving pattern matching over encrypted genetic data in cloud computing. IEEE INFOCOM 2017 - IEEE Conference on Computer Communications. :1–9.

Personalized medicine performs diagnoses and treatments according to the DNA information of the patients. The new paradigm will change the health care model in the future. A doctor will perform the DNA sequence matching instead of the regular clinical laboratory tests to diagnose and medicate the diseases. Additionally, with the help of the affordable personal genomics services such as 23andMe, personalized medicine will be applied to a great population. Cloud computing will be the perfect computing model as the volume of the DNA data and the computation over it are often immense. However, due to the sensitivity, the DNA data should be encrypted before being outsourced into the cloud. In this paper, we start from a practical system model of the personalize medicine and present a solution for the secure DNA sequence matching problem in cloud computing. Comparing with the existing solutions, our scheme protects the DNA data privacy as well as the search pattern to provide a better privacy guarantee. We have proved that our scheme is secure under the well-defined cryptographic assumption, i.e., the sub-group decision assumption over a bilinear group. Unlike the existing interactive schemes, our scheme requires only one round of communication, which is critical in practical application scenarios. We also carry out a simulation study using the real-world DNA data to evaluate the performance of our scheme. The simulation results show that the computation overhead for real world problems is practical, and the communication cost is small. Furthermore, our scheme is not limited to the genome matching problem but it applies to general privacy preserving pattern matching problems which is widely used in real world.

2018-01-16
Alanwar, A., Shoukry, Y., Chakraborty, S., Martin, P., Tabuada, P., Srivastava, M..  2017.  PrOLoc: Resilient Localization with Private Observers Using Partial Homomorphic Encryption. 2017 16th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN). :41–52.

This article presents PrOLoc, a localization system that combines partially homomorphic encryption with a new way of structuring the localization problem to enable emcient and accurate computation of a target's location while preserving the privacy of the observers.

Ding, Y., Li, X..  2017.  Policy Based on Homomorphic Encryption and Retrieval Scheme in Cloud Computing. 2017 IEEE International Conference on Computational Science and Engineering (CSE) and IEEE International Conference on Embedded and Ubiquitous Computing (EUC). 1:568–571.

Homomorphic encryption technology can settle a dispute of data privacy security in cloud environment, but there are many problems in the process of access the data which is encrypted by a homomorphic algorithm in the cloud. In this paper, on the premise of attribute encryption, we propose a fully homomorphic encrypt scheme which based on attribute encryption with LSSS matrix. This scheme supports fine-grained cum flexible access control along with "Query-Response" mechanism to enable users to efficiently retrieve desired data from cloud servers. In addition, the scheme should support considerable flexibility to revoke system privileges from users without updating the key client, it reduces the pressure of the client greatly. Finally, security analysis illustrates that the scheme can resist collusion attack. A comparison of the performance from existing CP-ABE scheme, indicates that our scheme reduces the computation cost greatly for users.

Ugwuoke, C., Erkin, Z., Lagendijk, R. L..  2017.  Privacy-safe linkage analysis with homomorphic encryption. 2017 25th European Signal Processing Conference (EUSIPCO). :961–965.

Genetic data are important dataset utilised in genetic epidemiology to investigate biologically coded information within the human genome. Enormous research has been delved into in recent years in order to fully sequence and understand the genome. Personalised medicine, patient response to treatments and relationships between specific genes and certain characteristics such as phenotypes and diseases, are positive impacts of studying the genome, just to mention a few. The sensitivity, longevity and non-modifiable nature of genetic data make it even more interesting, consequently, the security and privacy for the storage and processing of genomic data beg for attention. A common activity carried out by geneticists is the association analysis between allele-allele, or even a genetic locus and a disease. We demonstrate the use of cryptographic techniques such as homomorphic encryption schemes and multiparty computations, how such analysis can be carried out in a privacy friendly manner. We compute a 3 × 3 contingency table, and then, genome analyses algorithms such as linkage disequilibrium (LD) measures, all on the encrypted domain. Our computation guarantees privacy of the genome data under our security settings, and provides up to 98.4% improvement, compared to an existing solution.

Nasser, R., Renes, J. M..  2017.  Polar codes for arbitrary classical-quantum channels and arbitrary cq-MACs. 2017 IEEE International Symposium on Information Theory (ISIT). :281–285.

We prove polarization theorems for arbitrary classical-quantum (cq) channels. The input alphabet is endowed with an arbitrary Abelian group operation and an Arikan-style transformation is applied using this operation. It is shown that as the number of polarization steps becomes large, the synthetic cq-channels polarize to deterministic homomorphism channels that project their input to a quotient group of the input alphabet. This result is used to construct polar codes for arbitrary cq-channels and arbitrary classical-quantum multiple access channels (cq-MAC). The encoder can be implemented in O(N log N) operations, where N is the blocklength of the code. A quantum successive cancellation decoder for the constructed codes is proposed. It is shown that the probability of error of this decoder decays faster than 2-Nβ for any β textless; ½.

Zouari, J., Hamdi, M., Kim, T. H..  2017.  A privacy-preserving homomorphic encryption scheme for the Internet of Things. 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC). :1939–1944.

The Internet of Things is a disruptive paradigm based on the cooperation of a plethora of heterogeneous smart things to collect, transmit, and analyze data from the ambient environment. To this end, many monitored variables are combined by a data analysis module in order to implement efficient context-aware decision mechanisms. To ensure resource efficiency, aggregation is a long established solution, however it is applicable only in the case of one sensed variable. We extend the use of aggregation to the complex context of IoT by proposing a novel approach for secure cooperation of smart things while granting confidentiality and integrity. Traditional solutions for data concealment in resource constrained devices rely on hop-by-hop or end-to-end encryption, which are shown to be inefficient in our context. We use a more sophisticated scheme relying on homomorphic encryption which is not compromise resilient. We combine fully additive encryption with fully additive secret sharing to fulfill the required properties. Thorough security analysis and performance evaluation show a viable tradeoff between security and efficiency for our scheme.

Hesamifard, Ehsan, Takabi, Hassan, Ghasemi, Mehdi, Jones, Catherine.  2017.  Privacy-preserving Machine Learning in Cloud. Proceedings of the 2017 on Cloud Computing Security Workshop. :39–43.

Machine learning algorithms based on deep neural networks (NN) have achieved remarkable results and are being extensively used in different domains. On the other hand, with increasing growth of cloud services, several Machine Learning as a Service (MLaaS) are offered where training and deploying machine learning models are performed on cloud providers' infrastructure. However, machine learning algorithms require access to raw data which is often privacy sensitive and can create potential security and privacy risks. To address this issue, we develop new techniques to provide solutions for applying deep neural network algorithms to the encrypted data. In this paper, we show that it is feasible and practical to train neural networks using encrypted data and to make encrypted predictions, and also return the predictions in an encrypted form. We demonstrate applicability of the proposed techniques and evaluate its performance. The empirical results show that it provides accurate privacy-preserving training and classification.

Tang, Qiang, Wang, Husen.  2017.  Privacy-preserving Hybrid Recommender System. Proceedings of the Fifth ACM International Workshop on Security in Cloud Computing. :59–66.

Privacy issues in recommender systems have attracted the attention of researchers for many years. So far, a number of solutions have been proposed. Unfortunately, most of them are far from practical as they either downgrade the utility or are very inefficient. In this paper, we aim at a more practical solution, by proposing a privacy-preserving hybrid recommender system which consists of an incremental matrix factorization (IMF) component and a user-based collaborative filtering (UCF) component. The IMF component provides the fundamental utility while it allows the service provider to efficiently learn feature vectors in plaintext domain, and the UCF component improves the utility while allows users to carry out their computations in an offline manner. Leveraging somewhat homomorphic encryption (SWHE) schemes, we provide privacy-preserving candidate instantiations for both components. Our experiments demonstrate that the hybrid solution is much more efficient than existing solutions.

Huang, C., Hou, C., He, L., Dai, H., Ding, Y..  2017.  Policy-Customized: A New Abstraction for Building Security as a Service. 2017 14th International Symposium on Pervasive Systems, Algorithms and Networks 2017 11th International Conference on Frontier of Computer Science and Technology 2017 Third International Symposium of Creative Computing (ISPAN-FCST-ISCC). :203–210.

Just as cloud customers have different performance requirements, they also have different security requirements for their computations in the cloud. Researchers have suggested a "security on demand" service model for cloud computing, where secure computing environment are dynamically provisioned to cloud customers according to their specific security needs. The availability of secure computing platforms is a necessary but not a sufficient solution to convince cloud customers to move their sensitive data and code to the cloud. Cloud customers need further assurance to convince them that the security measures are indeed deployed, and are working correctly. In this paper, we present Policy-Customized Trusted Cloud Service architecture with a new remote attestation scheme and a virtual machine migration protocol, where cloud customer can custom security policy of computing environment and validate whether the current computing environment meets the security policy in the whole life cycle of the virtual machine. To prove the availability of proposed architecture, we realize a prototype that support customer-customized security policy and a VM migration protocol that support customer-customized migration policy and validation based on open source Xen Hypervisor.

Connell, Warren, Menascé, Daniel A., Albanese, Massimiliano.  2017.  Performance Modeling of Moving Target Defenses. Proceedings of the 2017 Workshop on Moving Target Defense. :53–63.

In recent years, Moving Target Defense (MTD) has emerged as a potential game changer in the security landscape, due to its potential to create asymmetric uncertainty that favors the defender. Many different MTD techniques have then been proposed, each addressing an often very specific set of attack vectors. Despite the huge progress made in this area, there are still some critical gaps with respect to the analysis and quantification of the cost and benefits of deploying MTD techniques. In fact, common metrics to assess the performance of these techniques are still lacking and most of them tend to assess their performance in different and often incompatible ways. This paper addresses these gaps by proposing a quantitative analytic model for assessing the resource availability and performance of MTDs, and a method for the determination of the highest possible reconfiguration rate, and thus smallest probability of attacker's success, that meets performance and stability constraints. Finally, we present an experimental validation of the proposed approach.

Sagisi, J., Tront, J., Bradley, R. M..  2017.  Platform agnostic, scalable, and unobtrusive FPGA network processor design of moving target defense over IPv6 (MT6D) over IEEE 802.3 Ethernet. 2017 IEEE International Symposium on Hardware Oriented Security and Trust (HOST). :165–165.

This work presents the proof of concept implementation for the first hardware-based design of Moving Target Defense over IPv6 (MT6D) in full Register Transfer Level (RTL) logic, with future sights on an embedded Application-Specified Integrated Circuit (ASIC) implementation. Contributions are an IEEE 802.3 Ethernet stream-based in-line network packet processor with a specialized Complex Instruction Set Computer (CISC) instruction set architecture, RTL-based Network Time Protocol v4 synchronization, and a modular crypto engine. Traditional static network addressing allows attackers the incredible advantage of taking time to plan and execute attacks against a network. To counter, MT6D provides a network host obfuscation technique that offers network-based keyed access to specific hosts without altering existing network infrastructure and is an excellent technique for protecting the Internet of Things, IPv6 over Low Power Wireless Personal Area Networks, and high value globally routable IPv6 interfaces. This is done by crypto-graphically altering IPv6 network addresses every few seconds in a synchronous manner at all endpoints. A border gateway device can be used to intercept select packets to unobtrusively perform this action. Software driven implementations have posed many challenges, namely, constant code maintenance to remain compliant with all library and kernel dependencies, the need for a host computing platform, and less than optimal throughput. This work seeks to overcome these challenges in a lightweight system to be developed for practical wide deployment.

Kansal, V., Dave, M..  2017.  Proactive DDoS attack detection and isolation. 2017 International Conference on Computer, Communications and Electronics (Comptelix). :334–338.

The increased number of cyber attacks makes the availability of services a major security concern. One common type of cyber threat is distributed denial of service (DDoS). A DDoS attack is aimed at disrupting the legitimate users from accessing the services. It is easier for an insider having legitimate access to the system to deceive any security controls resulting in insider attack. This paper proposes an Early Detection and Isolation Policy (EDIP)to mitigate insider-assisted DDoS attacks. EDIP detects insider among all legitimate clients present in the system at proxy level and isolate it from innocent clients by migrating it to attack proxy. Further an effective algorithm for detection and isolation of insider is developed with the aim of maximizing attack isolation while minimizing disruption to benign clients. In addition, concept of load balancing is used to prevent proxies from getting overloaded.

Gurjar, S. P. S., Pasupuleti, S. K..  2016.  A privacy-preserving multi-keyword ranked search scheme over encrypted cloud data using MIR-tree. 2016 International Conference on Computing, Analytics and Security Trends (CAST). :533–538.

With increasing popularity of cloud computing, the data owners are motivated to outsource their sensitive data to cloud servers for flexibility and reduced cost in data management. However, privacy is a big concern for outsourcing data to the cloud. The data owners typically encrypt documents before outsourcing for privacy-preserving. As the volume of data is increasing at a dramatic rate, it is essential to develop an efficient and reliable ciphertext search techniques, so that data owners can easily access and update cloud data. In this paper, we propose a privacy preserving multi-keyword ranked search scheme over encrypted data in cloud along with data integrity using a new authenticated data structure MIR-tree. The MIR-tree based index with including the combination of widely used vector space model and TF×IDF model in the index construction and query generation. We use inverted file index for storing word-digest, which provides efficient and fast relevance between the query and cloud data. Design an authentication set(AS) for authenticating the queries, for verifying top-k search results. Because of tree based index, our scheme achieves optimal search efficiency and reduces communication overhead for verifying the search results. The analysis shows security and efficiency of our scheme.

Ghutugade, K. B., Patil, G. A..  2016.  Privacy preserving auditing for shared data in cloud. 2016 International Conference on Computing, Analytics and Security Trends (CAST). :300–305.

Cloud computing, often referred to as simply “the cloud,” is the delivery of on-demand computing resources; everything from applications to data centers over the Internet. Cloud is used not only for storing data, but also the stored data can be shared by multiple users. Due to this, the integrity of cloud data is subject to doubt. Every time it is not possible for user to download all data and verify integrity, so proposed system contain Third Party Auditor (TPA) to verify the integrity of shared data. During auditing, the shared data is kept private from public verifiers, who are able to verify shared data integrity without downloading or retrieving the entire data file. Group signature is used to preserve identity privacy of group members from third party auditor. Privacy preserving is done to ensure that the TPA cannot derive user's data content from the information collected during the auditing process.

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.
Alwen, Joel, Blocki, Jeremiah, Harsha, Ben.  2017.  Practical Graphs for Optimal Side-Channel Resistant Memory-Hard Functions. Proceedings of the 2017 ACM SIGSAC Conference on Computer and Communications Security. :1001–1017.
A memory-hard function (MHF) ƒn with parameter n can be computed in sequential time and space n. Simultaneously, a high amortized parallel area-time complexity (aAT) is incurred per evaluation. In practice, MHFs are used to limit the rate at which an adversary (using a custom computational device) can evaluate a security sensitive function that still occasionally needs to be evaluated by honest users (using an off-the-shelf general purpose device). The most prevalent examples of such sensitive functions are Key Derivation Functions (KDFs) and password hashing algorithms where rate limits help mitigate off-line dictionary attacks. As the honest users' inputs to these functions are often (low-entropy) passwords special attention is given to a class of side-channel resistant MHFs called iMHFs. Essentially all iMHFs can be viewed as some mode of operation (making n calls to some round function) given by a directed acyclic graph (DAG) with very low indegree. Recently, a combinatorial property of a DAG has been identified (called "depth-robustness") which results in good provable security for an iMHF based on that DAG. Depth-robust DAGs have also proven useful in other cryptographic applications. Unfortunately, up till now, all known very depth-robust DAGs are impractically complicated and little is known about their exact (i.e. non-asymptotic) depth-robustness both in theory and in practice. In this work we build and analyze (both formally and empirically) several exceedingly simple and efficient to navigate practical DAGs for use in iMHFs and other applications. For each DAG we: Prove that their depth-robustness is asymptotically maximal. Prove bounds of at least 3 orders of magnitude better on their exact depth-robustness compared to known bounds for other practical iMHF. Implement and empirically evaluate their depth-robustness and aAT against a variety of state-of-the art (and several new) depth-reduction and low aAT attacks. We find that, against all attacks, the new DAGs perform significantly better in practice than Argon2i, the most widely deployed iMHF in practice. Along the way we also improve the best known empirical attacks on the aAT of Argon2i by implementing and testing several heuristic versions of a (hitherto purely theoretical) depth-reduction attack. Finally, we demonstrate practicality of our constructions by modifying the Argon2i code base to use one of the new high aAT DAGs. Experimental benchmarks on a standard off-the-shelf CPU show that the new modifications do not adversely affect the impressive throughput of Argon2i (despite seemingly enjoying significantly higher aAT).
Hu, Qinghao, Wu, Jiaxiang, Cheng, Jian, Wu, Lifang, Lu, Hanqing.  2017.  Pseudo Label Based Unsupervised Deep Discriminative Hashing for Image Retrieval. Proceedings of the 2017 ACM on Multimedia Conference. :1584–1590.

Hashing methods play an important role in large scale image retrieval. Traditional hashing methods use hand-crafted features to learn hash functions, which can not capture the high level semantic information. Deep hashing algorithms use deep neural networks to learn feature representation and hash functions simultaneously. Most of these algorithms exploit supervised information to train the deep network. However, supervised information is expensive to obtain. In this paper, we propose a pseudo label based unsupervised deep discriminative hashing algorithm. First, we cluster images via K-means and the cluster labels are treated as pseudo labels. Then we train a deep hashing network with pseudo labels by minimizing the classification loss and quantization loss. Experiments on two datasets demonstrate that our unsupervised deep discriminative hashing method outperforms the state-of-art unsupervised hashing methods.

Zhang, Yuexin, Xiang, Yang, Huang, Xinyi.  2016.  Password-Authenticated Group Key Exchange: A Cross-Layer Design. ACM Trans. Internet Technol.. 16:24:1–24:20.
Two-party password-authenticated key exchange (2PAKE) protocols provide a natural mechanism for secret key establishment in distributed applications, and they have been extensively studied in past decades. However, only a few efforts have been made so far to design password-authenticated group key exchange (GPAKE) protocols. In a 2PAKE or GPAKE protocol, it is assumed that short passwords are preshared among users. This assumption, however, would be impractical in certain applications. Motivated by this observation, this article presents a GPAKE protocol without the password sharing assumption. To obtain the passwords, wireless devices, such as smart phones, tablets, and laptops, are used to extract short secrets at the physical layer. Using the extracted secrets, users in our protocol can establish a group key at higher layers with light computation consumptions. Thus, our GPAKE protocol is a cross-layer design. Additionally, our protocol is a compiler, that is, our protocol can transform any provably secure 2PAKE protocol into a GPAKE protocol with only one more round of communications. Besides, the proposed protocol is proved secure in the standard model.