Visible to the public Biblio

Found 1515 results

Filters: First Letter Of Title is S  [Clear All Filters]
A B C D E F G H I J K L M N O P Q R [S] T U V W X Y Z   [Show ALL]
S
Wu, Xingbo, Ni, Fan, Jiang, Song.  2017.  Search Lookaside Buffer: Efficient Caching for Index Data Structures. Proceedings of the 2017 Symposium on Cloud Computing. :27–39.
With the ever increasing DRAM capacity in commodity computers, applications tend to store large amount of data in main memory for fast access. Accordingly, efficient traversal of index structures to locate requested data becomes crucial to their performance. The index data structures grow so large that only a fraction of them can be cached in the CPU cache. The CPU cache can leverage access locality to keep the most frequently used part of an index in it for fast access. However, the traversal on the index to a target data during a search for a data item can result in significant false temporal and spatial localities, which make CPU cache space substantially underutilized. In this paper we show that even for highly skewed accesses the index traversal incurs excessive cache misses leading to suboptimal data access performance. To address the issue, we introduce Search Lookaside Buffer (SLB) to selectively cache only the search results, instead of the index itself. SLB can be easily integrated with any index data structure to increase utilization of the limited CPU cache resource and improve throughput of search requests on a large data set. We integrate SLB with various index data structures and applications. Experiments show that SLB can improve throughput of the index data structures by up to an order of magnitude. Experiments with real-world key-value traces also show up to 73% throughput improvement on a hash table.
Kim, Donghoon, Sample, Luke.  2019.  Search Prevention with Captcha Against Web Indexing: A Proof of Concept. 2019 IEEE International Conference on Computational Science and Engineering (CSE) and IEEE International Conference on Embedded and Ubiquitous Computing (EUC). :219—224.
A website appears in search results based on web indexing conducted by a search engine bot (e.g., a web crawler). Some webpages do not want to be found easily because they include sensitive information. There are several methods to prevent web crawlers from indexing in search engine database. However, such webpages can still be indexed by malicious web crawlers. Through this study, we explore a paradox perspective on a new use of captchas for search prevention. Captchas are used to prevent web crawlers from indexing by converting sensitive words to captchas. We have implemented the web-based captcha conversion tool based on our search prevention algorithm. We also describe our proof of concept with the web-based chat application modified to utilize our algorithm. We have conducted the experiment to evaluate our idea on Google search engine with two versions of webpages, one containing plain text and another containing sensitive words converted to captchas. The experiment results show that the sensitive words on the captcha version of the webpages are unable to be found by Google's search engine, while the plain text versions are.
Rahman, Mizanur, Hernandez, Nestor, Carbunar, Bogdan, Chau, Duen Horng.  2018.  Search Rank Fraud De-Anonymization in Online Systems. Proceedings of the 29th on Hypertext and Social Media. :174–182.

We introduce the fraud de-anonymization problem, that goes beyond fraud detection, to unmask the human masterminds responsible for posting search rank fraud in online systems. We collect and study search rank fraud data from Upwork, and survey the capabilities and behaviors of 58 search rank fraudsters recruited from 6 crowdsourcing sites. We propose Dolos, a fraud de-anonymization system that leverages traits and behaviors extracted from these studies, to attribute detected fraud to crowdsourcing site fraudsters, thus to real identities and bank accounts. We introduce MCDense, a min-cut dense component detection algorithm to uncover groups of user accounts controlled by different fraudsters, and leverage stylometry and deep learning to attribute them to crowdsourcing site profiles. Dolos correctly identified the owners of 95% of fraudster-controlled communities, and uncovered fraudsters who promoted as many as 97.5% of fraud apps we collected from Google Play. When evaluated on 13,087 apps (820,760 reviews), which we monitored over more than 6 months, Dolos identified 1,056 apps with suspicious reviewer groups. We report orthogonal evidence of their fraud, including fraud duplicates and fraud re-posts.

Zeng, Ming, Zhang, Kai, Qian, Haifeng, Chen, Xiaofeng, Chen, Jie, Mu, Yi.  2019.  A Searchable Asymmetric Encryption Scheme with Support for Boolean Queries for Cloud Applications. The Computer Journal. 62:563–578.
Cloud computing is a new promising technology paradigm that can provide clients from the whole network with scalable storage resources and on-demand high-quality services. However, security concerns are raised when sensitive data are outsourced. Searchable encryption is a kind of cryptographic primitive that enables clients to selectively retrieve encrypted data, the existing schemes that support for sub-linear boolean queries are only considered in symmetric key setting, which makes a limitation for being widely deployed in many cloud applications. In order to address this issue, we propose a novel searchable asymmetric encryption scheme to support for sub-linear boolean query over encrypted data in a multi-client model that is extracted from an important observation that the outsourced database in cloud is continuously contributed and searched by multiple clients. For the purpose of introducing the scheme, we combine both the ideas of symmetric searchable encryption and public key searchable encryption and then design a novel secure inverted index. Furthermore, a detailed security analysis for our scheme is given under the simulation-based security definition. Finally, we conduct experiments for our construction on a real dataset (Enron) along with a performance analysis to show its practicality.
Zhao, Zhiyuan, Sun, Lei, Li, Zuohui, Liu, Ying.  2018.  Searchable Ciphertext-Policy Attribute-Based Encryption with Multi-Keywords for Secure Cloud Storage. Proceedings of the 2018 International Conference on Computing and Pattern Recognition. :35–41.
Searchable encryption is one of the most important techniques for the sensitive data outsourced to cloud server, and has been widely used in cloud storage which brings huge convenience and saves bandwidth and computing resources. A novel searchable cryptographic scheme is proposed by which data owner can control the search and use of the outsourced encrypted data according to its access control policy. The scheme is called searchable ciphertext-policy attribute-based encryption with multikeywords (CPABMKS). In the scheme, CP-ABE and keywords are combined together through the way that the keywords are regarded as the file attributes. To overcome the previous problems in cloud storage, access structures are hidden so that receivers cannot extract sensitive information from the ciphertext. At the same time, this scheme supports the multi-keywords search, and the data owner can outsource the encryption operations to the private cloud that can reduce the data owner' calculation. The security of this scheme is proved based on the DBDH assumption. Finally, scheme evaluation shows that the CPABMKS scheme is practical
Cao, L., Kang, Y., Wu, Q., Wu, R., Guo, X., Feng, T..  2020.  Searchable encryption cloud storage with dynamic data update to support efficient policy hiding. China Communications. 17:153–163.
Ciphertext policy attribute based encryption (CP-ABE) can provide high finegrained access control for cloud storage. However, it needs to solve problems such as property privacy protection, ciphertext search and data update in the application process. Therefore, based on CP-ABE scheme, this paper proposes a dynamically updatable searchable encryption cloud storage (DUSECS) scheme. Using the characteristics of homomorphic encryption, the encrypted data is compared to achieve efficient hiding policy. Meanwhile, adopting linked list structure, the DUSECS scheme realizes the dynamic data update and integrity detection, and the search encryption against keyword guessing attacks is achieved by combining homomorphic encryption with aggregation algorithm. The analysis of security and performance shows that the scheme is secure and efficient.
Mohd Kamal, Ahmad Akmal Aminuddin, Iwamura, Keiichi.  2019.  Searchable Encryption Using Secret-Sharing Scheme for Multiple Keyword Search Using Conjunctive and Disjunctive Searching. 2019 IEEE Intl Conf on Dependable, Autonomic and Secure Computing, Intl Conf on Pervasive Intelligence and Computing, Intl Conf on Cloud and Big Data Computing, Intl Conf on Cyber Science and Technology Congress (DASC/PiCom/CBDCom/CyberSciTech). :149–156.
The main searching functions realized by searchable encryption can be divided into searching using one query and searching using multiple queries. Searchable encryption using one query has been widely studied and researched; however, few methods of searchable encryption can accommodate search using multiple queries. In addition, most of the method proposed thus far utilize the concept of index search. Therefore, a new problem exists, in which an additional process of updating or deleting an index when new documents are added or removed is required. Hence, the overall computation cost increases. Another problem is that a document that is not registered in the index cannot be searched. Therefore, herein, using a secret-sharing scheme that is known to offer a low computational cost, we propose a method that can realize both logical conjunctive (AND) and logical disjunctive (OR) search over multiple conditions, without the construction of any index. Hence, we can realize direct searching over sentences, thus achieving a more efficient search method.
Poh, Geong Sen, Chin, Ji-Jian, Yau, Wei-Chuen, Choo, Kim-Kwang Raymond, Mohamad, Moesfa Soeheila.  2017.  Searchable Symmetric Encryption: Designs and Challenges. ACM Comput. Surv.. 50:40:1–40:37.
Searchable Symmetric Encryption (SSE) when deployed in the cloud allows one to query encrypted data without the risk of data leakage. Despite the widespread interest, existing surveys do not examine in detail how SSE’s underlying structures are designed and how these result in the many properties of a SSE scheme. This is the gap we seek to address, as well as presenting recent state-of-the-art advances on SSE. Specifically, we present a general framework and believe the discussions may lead to insights for potential new designs. We draw a few observations. First, most schemes use index table, where optimal index size and sublinear search can be achieved using an inverted index. Straightforward updating can only be achieved using direct index, but search time would be linear. A recent trend is the combinations of index table, and tree, deployed for efficient updating and storage. Secondly, mechanisms from related fields such as Oblivious RAM (ORAM) have been integrated to reduce leakages. However, using these mechanisms to minimise leakages in schemes with richer functionalities (e.g., ranked, range) is relatively unexplored. Thirdly, a new approach (e.g., multiple servers) is required to mitigate new and emerging attacks on leakage. Lastly, we observe that a proposed index may not be practically efficient when implemented, where I/O access must be taken into consideration.
Asharov, Gilad, Naor, Moni, Segev, Gil, Shahaf, Ido.  2016.  Searchable Symmetric Encryption: Optimal Locality in Linear Space via Two-dimensional Balanced Allocations. Proceedings of the Forty-eighth Annual ACM Symposium on Theory of Computing. :1101–1114.

Searchable symmetric encryption (SSE) enables a client to store a database on an untrusted server while supporting keyword search in a secure manner. Despite the rapidly increasing interest in SSE technology, experiments indicate that the performance of the known schemes scales badly to large databases. Somewhat surprisingly, this is not due to their usage of cryptographic tools, but rather due to their poor locality (where locality is defined as the number of non-contiguous memory locations the server accesses with each query). The only known schemes that do not suffer from poor locality suffer either from an impractical space overhead or from an impractical read efficiency (where read efficiency is defined as the ratio between the number of bits the server reads with each query and the actual size of the answer). We construct the first SSE schemes that simultaneously enjoy optimal locality, optimal space overhead, and nearly-optimal read efficiency. Specifically, for a database of size N, under the modest assumption that no keyword appears in more than N1 − 1/loglogN documents, we construct a scheme with read efficiency Õ(loglogN). This essentially matches the lower bound of Cash and Tessaro (EUROCRYPT ’14) showing that any SSE scheme must be sub-optimal in either its locality, its space overhead, or its read efficiency. In addition, even without making any assumptions on the structure of the database, we construct a scheme with read efficiency Õ(logN). Our schemes are obtained via a two-dimensional generalization of the classic balanced allocations (“balls and bins”) problem that we put forward. We construct nearly-optimal two-dimensional balanced allocation schemes, and then combine their algorithmic structure with subtle cryptographic techniques.

Asharov, Gilad, Naor, Moni, Segev, Gil, Shahaf, Ido.  2016.  Searchable Symmetric Encryption: Optimal Locality in Linear Space via Two-dimensional Balanced Allocations. Proceedings of the Forty-eighth Annual ACM Symposium on Theory of Computing. :1101–1114.

Searchable symmetric encryption (SSE) enables a client to store a database on an untrusted server while supporting keyword search in a secure manner. Despite the rapidly increasing interest in SSE technology, experiments indicate that the performance of the known schemes scales badly to large databases. Somewhat surprisingly, this is not due to their usage of cryptographic tools, but rather due to their poor locality (where locality is defined as the number of non-contiguous memory locations the server accesses with each query). The only known schemes that do not suffer from poor locality suffer either from an impractical space overhead or from an impractical read efficiency (where read efficiency is defined as the ratio between the number of bits the server reads with each query and the actual size of the answer). We construct the first SSE schemes that simultaneously enjoy optimal locality, optimal space overhead, and nearly-optimal read efficiency. Specifically, for a database of size N, under the modest assumption that no keyword appears in more than N1 − 1/loglogN documents, we construct a scheme with read efficiency Õ(loglogN). This essentially matches the lower bound of Cash and Tessaro (EUROCRYPT ’14) showing that any SSE scheme must be sub-optimal in either its locality, its space overhead, or its read efficiency. In addition, even without making any assumptions on the structure of the database, we construct a scheme with read efficiency Õ(logN). Our schemes are obtained via a two-dimensional generalization of the classic balanced allocations (“balls and bins”) problem that we put forward. We construct nearly-optimal two-dimensional balanced allocation schemes, and then combine their algorithmic structure with subtle cryptographic techniques.

Arrieta, Aitor, Wang, Shuai, Sagardui, Goiuria, Etxeberria, Leire.  2016.  Search-based Test Case Selection of Cyber-physical System Product Lines for Simulation-based Validation. Proceedings of the 20th International Systems and Software Product Line Conference. :297–306.

Cyber-Physical Systems (CPSs) are often tested at different test levels following "X-in-the-Loop" configurations: Model-, Software- and Hardware-in-the-loop (MiL, SiL and HiL). While MiL and SiL test levels aim at testing functional requirements at the system level, the HiL test level tests functional as well as non-functional requirements by performing a real-time simulation. As testing CPS product line configurations is costly due to the fact that there are many variants to test, test cases are long, the physical layer has to be simulated and co-simulation is often necessary. It is therefore extremely important to select the appropriate test cases that cover the objectives of each level in an allowable amount of time. We propose an efficient test case selection approach adapted to the "X-in-the-Loop" test levels. Search algorithms are employed to reduce the amount of time required to test configurations of CPS product lines while achieving the test objectives of each level. We empirically evaluate three commonly-used search algorithms, i.e., Genetic Algorithm (GA), Alternating Variable Method (AVM) and Greedy (Random Search (RS) is used as a baseline) by employing two case studies with the aim of integrating the best algorithm into our approach. Results suggest that as compared with RS, our approach can reduce the costs of testing CPS product line configurations by approximately 80% while improving the overall test quality.

Wang, Yao, Ferraiuolo, Andrew, Zhang, Danfeng, Myers, Andrew C., Suh, G. Edward.  2016.  SecDCP: Secure Dynamic Cache Partitioning for Efficient Timing Channel Protection. Proceedings of the 53rd Annual Design Automation Conference. :74:1–74:6.

In today's multicore processors, the last-level cache is often shared by multiple concurrently running processes to make efficient use of hardware resources. However, previous studies have shown that a shared cache is vulnerable to timing channel attacks that leak confidential information from one process to another. Static cache partitioning can eliminate the cache timing channels but incurs significant performance overhead. In this paper, we propose Secure Dynamic Cache Partitioning (SecDCP), a partitioning technique that defeats cache timing channel attacks. The SecDCP scheme changes the size of cache partitions at run time for better performance while preventing insecure information leakage between processes. For cache-sensitive multiprogram workloads, our experimental results show that SecDCP improves performance by up to 43% and by an average of 12.5% over static cache partitioning.

Wang, Qian, Wang, Jingjun, Hu, Shengshan, Zou, Qin, Ren, Kui.  2016.  SecHOG: Privacy-Preserving Outsourcing Computation of Histogram of Oriented Gradients in the Cloud. Proceedings of the 11th ACM on Asia Conference on Computer and Communications Security. :257–268.

Abundant multimedia data generated in our daily life has intrigued a variety of very important and useful real-world applications such as object detection and recognition etc. Accompany with these applications, many popular feature descriptors have been developed, e.g., SIFT, SURF and HOG. Manipulating massive multimedia data locally, however, is a storage and computation intensive task, especially for resource-constrained clients. In this work, we focus on exploring how to securely outsource the famous feature extraction algorithm–Histogram of Oriented Gradients (HOG) to untrusted cloud servers, without revealing the data owner's private information. For the first time, we investigate this secure outsourcing computation problem under two different models and accordingly propose two novel privacy-preserving HOG outsourcing protocols, by efficiently encrypting image data by somewhat homomorphic encryption (SHE) integrated with single-instruction multiple-data (SIMD), designing a new batched secure comparison protocol, and carefully redesigning every step of HOG to adapt it to the ciphertext domain. Explicit Security and effectiveness analysis are presented to show that our protocols are practically-secure and can approximate well the performance of the original HOG executed in the plaintext domain. Our extensive experimental evaluations further demonstrate that our solutions achieve high efficiency and perform comparably to the original HOG when being applied to human detection.

Ghiglieri, Marco, Stopczynski, Martin.  2016.  SecLab: An Innovative Approach to Learn and Understand Current Security and Privacy Issues. Proceedings of the 17th Annual Conference on Information Technology Education. :67–72.

Security and privacy are crucial for all IT systems and services. The diversity of applications places high demands on the knowledge and experience of software developers and IT professionals. Besides programming skills, security and privacy aspects are required as well and must be considered during development. If developers have not been trained in these topics, it is especially difficult for them to prevent problematic security issues such as vulnerabilities. In this work we present an interactive e-learning platform focusing on solving real-world cybersecurity tasks in a sandboxed web environment. With our platform students can learn and understand how security vulnerabilities can be exploited in different scenarios. The platform has been evaluated in four university IT security courses with around 1100 participants over three years.

Wu, Di, Chen, Tianen, Chen, Chienfu, Ahia, Oghenefego, Miguel, Joshua San, Lipasti, Mikko, Kim, Younghyun.  2019.  SECO: A Scalable Accuracy Approximate Exponential Function Via Cross-Layer Optimization. 2019 IEEE/ACM International Symposium on Low Power Electronics and Design (ISLPED). :1–6.

From signal processing to emerging deep neural networks, a range of applications exhibit intrinsic error resilience. For such applications, approximate computing opens up new possibilities for energy-efficient computing by producing slightly inaccurate results using greatly simplified hardware. Adopting this approach, a variety of basic arithmetic units, such as adders and multipliers, have been effectively redesigned to generate approximate results for many error-resilient applications.In this work, we propose SECO, an approximate exponential function unit (EFU). Exponentiation is a key operation in many signal processing applications and more importantly in spiking neuron models, but its energy-efficient implementation has been inadequately explored. We also introduce a cross-layer design method for SECO to optimize the energy-accuracy trade-off. At the algorithm level, SECO offers runtime scaling between energy efficiency and accuracy based on approximate Taylor expansion, where the error is minimized by optimizing parameters using discrete gradient descent at design time. At the circuit level, our error analysis method efficiently explores the design space to select the energy-accuracy-optimal approximate multiplier at design time. In tandem, the cross-layer design and runtime optimization method are able to generate energy-efficient and accurate approximate EFU designs that are up to 99.7% accurate at a power consumption of 3.73 pJ per exponential operation. SECO is also evaluated on the adaptive exponential integrate-and-fire neuron model, yielding only 0.002% timing error and 0.067% value error compared to the precise neuron model.

Saito, Takumi, Zhao, Qiangfu, Naito, Hiroshi.  2019.  Second Level Steganalysis - Embeding Location Detection Using Machine Learning. 2019 IEEE 10th International Conference on Awareness Science and Technology (iCAST). :1–6.

In recent years, various cloud-based services have been introduced in our daily lives, and information security is now an important topic for protecting the users. In the literature, many technologies have been proposed and incorporated into different services. Data hiding or steganography is a data protection technology, and images are often used as the cover data. On the other hand, steganalysis is an important tool to test the security strength of a steganography technique. So far, steganalysis has been used mainly for detecting the existence of secret data given an image, i.e., to classify if the given image is a normal or a stego image. In this paper, we investigate the possibility of identifying the locations of the embedded data if the a given image is suspected to be a stego image. The purpose is of two folds. First, we would like to confirm the decision made by the first level steganalysis; and the second is to provide a way to guess the size of the embedded data. Our experimental results show that in most cases the embedding positions can be detected. This result can be useful for developing more secure steganography technologies.

Wang, J., Lin, S., Liu, C., Wang, J., Zhu, B., Jiang, Y..  2018.  Secrecy Capacity of Indoor Visible Light Communication Channels. 2018 IEEE International Conference on Communications Workshops (ICC Workshops). :1–6.
In the indoor scenario, visible light communications (VLC) is regarded as one of the most promising candidates for future wireless communications. Recently, the physical layer security for indoor VLC has drawn considerable attention. In this paper, the secrecy capacity of indoor VLC is analyzed. Initially, an VLC system with a transmitter, a legitimate receiver, and an eavesdropper is established. In the system, the nonnegativity, the peak optical intensity constraint and the dimmable average optical intensity constraint are considered. Based on the principle of information theory, the closed-form expressions of the upper and the lower bounds on the secrecy capacity are derived, respectively. Numerical results show that the upper and the lower bounds on secrecy capacity are very tight, which verify the accuracy of the derived closed-form expressions.
Li, C., He, J., Liu, S., Guo, D., Song, L..  2020.  On Secrecy Key of a class of Secure Asymmetric Multilevel Diversity Coding System. 2020 IEEE International Symposium on Information Theory (ISIT). :879—883.
With the explosive development of big data, it is necessary to sort the data according to their importance or priorities. The sources with different importance levels can be modeled by the multilevel diversity coding systems (MDCS). Another trend in future communication networks, say 5G wireless networks and Internet of Things, is that users may obtain their data from all available sources, even from devices belonging to other users. Then, the privacy of data becomes a crucial issue. In a recent work by Li et al., the secure asymmetric MDCS (S-AMDCS) with wiretap channels was investigated, where the wiretapped messages do not leak any information about the sources (i.e. perfect secrecy). It was shown that superposition (source-separate coding) is not optimal for the general S-AMDCS and the exact full secure rate region was proved for a class of S-AMDCS. In addition, a bound on the key size of the secure rate region was provided as well. As a further step on the SAMDCS problem, this paper mainly focuses on the key size characterization. Specifically, the constraints on the key size of superposition secure rate region are proved and a counterexample is found to show that the bound on the key size of the exact secure rate region provided by Li et al. is not tight. In contrast, tight necessary and sufficient constraints on the secrecy key size of the counterexample, which is the four-encoder S-AMDCS, are proved.
Bouabdellah, Mounia, El Bouanani, Faissal, Ben-azza, Hussain.  2018.  Secrecy Outage Performance for Dual-Hop Underlay Cognitive Radio System over Nakagami-m Fading. Proceedings of the 2Nd International Conference on Smart Digital Environment. :70–75.

In this paper, the security performance of a dual-hop underlay cognitive radio (CR) system is investigated. In this system, we consider that the transmitted information by a source node S is forwarded by a multi-antenna relay R to its intended destination D. The relay performs the maximal-ratio combining (MRC) technique to process the multiple copies of the received signal. We also consider the presence of an eavesdropper who is attempting to intercept the transmitted information at both communication links, (i.e, S-R and R-D). In underlay cognitive radio networks (CRN), the source and the relay are required to adjust their transmission power to avoid causing interference to the primary user. Under this constraint, a closed-form expression of the secrecy outage probability is derived subject to Nakagami-m fading model. The derived expression is validated using Monte-Carlo simulation for various values of fading severity parameters as well as the number of MRC branches.

Qiu, Yu, Wang, Jin-Yuan, Lin, Sheng-Hong, Wang, Jun-Bo, Lin, Min.  2019.  Secrecy Outage Probability Analysis for Visible Light Communications with SWIPT and Random Terminals. 2019 11th International Conference on Wireless Communications and Signal Processing (WCSP). :1–6.
This paper investigates the physical-layer data secure transmission for indoor visible light communications (VLC) with simultaneous wireless information and power transfer (SWIPT) and random terminals. A typical indoor VLC system including one transmitter, one desired information receiver and one energy receiver is considered. The two receivers are randomly deployed on the floor, and the random channel characteristics is analyzed. Based on the possibility that the energy receiver is a passive information eavesdropper, the secrecy outage probability (SOP) is employed to evaluate the system performance. A closed-from expression for the lower bound of the SOP is obtained. For the derived lower bound of SOP, the theoretical results match the simulation results very well, which indicates that the derived lower bound can be used to evaluate the secrecy performance. Moreover, the gap between the results of the lower bound and the exact simulation results is also small, which verifies the correctness of the analysis method to obtain the lower bound.
Azaman, M. A. bin, Nguyen, N. P., Ha, D. B., Truong, T. V..  2017.  Secrecy outage probability of full-duplex networks with cognitive radio environment and partial relay selection. 2017 International Conference on Recent Advances in Signal Processing, Telecommunications Computing (SigTelCom). :119–123.

This paper investigates the secrecy performance of full-duplex relay mode in underlay cognitive radio networks using decode-and-forward relay selection. The analytical results prove that full-duplex mode can guarantee security under critical conditions such as the bad residual self-interference and the presence of hi-tech eavesdropper. The secrecy outage probability is derived based on the statistical characteristics of channels in this considered system. The system is examined under five circumferences: 1) Different values of primary network's desired outage probability; 2) Different values of primary transmitter's transmit power; 3) Applying of multiple relays selection; 4) Systems undergo path-loss during the transmission process; 5) Systems undergo self-interference in relays. Simulation results are presented to verify the analysis.

Sun, Yu, Zhao, Xiang.  2020.  On the Secrecy Performance of Random Mobile User in Visible Light Communication Systems. 2020 12th International Conference on Communication Software and Networks (ICCSN). :172–177.
For most of the current research on physical-layer security in indoor visible light communication (VLC) systems, a static communication environment was mainly considered, where secure communication about static users was investigated. However, much secure problems remain to be settled about mobile users. To improve the secrecy performance of mobile users, a two-dimensional circular optical atto-cell with security protected zone is considered. The proposed VLC systems include a LED transmitter Alice, a mobile user Bob and a passive eavesdropper Eve. A typical random waypoint model (RWP) being assumed, the secrecy outage probability (SOP) and secrecy throughput (ST) have been investigated for mobile users in VLC systems. The theoretical analysis results have been verified through Monte Carlo simulations. The simulation results show that the secrecy performance of mobile users in VLC can be improved by enlarging the radius of protected zone, and it also depends on the target secrecy rate and the LEDs' configuration.
Ge, Hong, Dai, Jianxin, Huang, Bo, Wang, Jin-Yuan.  2019.  Secrecy Rate Analysis for Visible Light Communications Using Spatial Modulation. 2019 IEEE 21st International Conference on High Performance Computing and Communications; IEEE 17th International Conference on Smart City; IEEE 5th International Conference on Data Science and Systems (HPCC/SmartCity/DSS). :1241–1248.
This paper mainly investigates the physical layer security for visible light communication (VLC) based on spatial modulation (SM). The indoor VLC system includes multiple transmitters, a legitimate receiver and an eavesdropper. In the system, we consider two constraints of the input signal: non-negative and dimmable average optical intensity constraints. According to the principle of information theory and the spatial modulation scheme of uniform selection (US), the upper and the lower bounds on the secrecy rate for SM based VLC are derived, respectively. Numerical results show that the performance gap between the upper and lower bounds of the secrecy rate is small and relatively close, which indicates that the derived secrecy rate bounds can be used to evaluate the system performance. Moreover, when the number of transmitters is set to be one, the spatial modulation disappears, and the secrecy rate bounds in this paper are consistent with the existing results. To further improve the secrecy performance, a channel adaptive selection (CAS) scheme is proposed for selecting the active transmitter. Numerical result indicates that the CAS scheme has better performance than the US scheme.
Pasolini, G., Dardari, D..  2014.  Secret key generation in correlated multi-dimensional Gaussian channels. Communications (ICC), 2014 IEEE International Conference on. :2171-2177.

Wireless channel reciprocity can be successfully exploited as a common source of randomness for the generation of a secret key by two legitimate users willing to achieve confidential communications over a public channel. This paper presents an analytical framework to investigate the theoretical limits of secret-key generation when wireless multi-dimensional Gaussian channels are used as source of randomness. The intrinsic secrecy content of wide-sense stationary wireless channels in frequency, time and spatial domains is derived through asymptotic analysis as the number of observations in a given domain tends to infinity. Some significant case studies are presented where single and multiple antenna eavesdroppers are considered. In the numerical results, the role of signal-to-noise ratio, spatial correlation, frequency and time selectivity is investigated.

Felsch, Dennis, Mainka, Christian, Mladenov, Vladislav, Schwenk, Jörg.  2017.  SECRET: On the Feasibility of a Secure, Efficient, and Collaborative Real-Time Web Editor. Proceedings of the 2017 ACM on Asia Conference on Computer and Communications Security. :835–848.
Real-time editing tools like Google Docs, Microsoft Office Online, or Etherpad have changed the way of collaboration. Many of these tools are based on Operational Transforms (OT), which guarantee that the views of different clients onto a document remain consistent over time. Usually, documents and operations are exposed to the server in plaintext – and thus to administrators, governments, and potentially cyber criminals. Therefore, it is highly desirable to work collaboratively on encrypted documents. Previous implementations do not unleash the full potential of this idea: They either require large storage, network, and computation overhead, are not real-time collaborative, or do not take the structure of the document into account. The latter simplifies the approach since only OT algorithms for byte sequences are required, but the resulting ciphertexts are almost four times the size of the corresponding plaintexts. We present SECRET, the first secure, efficient, and collaborative real-time editor. In contrast to all previous works, SECRET is the first tool that (1.) allows the encryption of whole documents or arbitrary sub-parts thereof, (2.) uses a novel combination of tree-based OT with a structure preserving encryption, and (3.) requires only a modern browser without any extra software installation or browser extension. We evaluate our implementation and show that its encryption overhead is three times smaller in comparison to all previous approaches. SECRET can even be used by multiple users in a low-bandwidth scenario. The source code of SECRET is published on GitHub as an open-source project:https://github.com/RUB-NDS/SECRET/