Biblio
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Towards Reliable Spatial Memory Safety for Embedded Software by Combining Checked C with Concolic Testing. 2021 58th ACM/IEEE Design Automation Conference (DAC). :667—672.
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2021. In this paper we propose to combine the safe C dialect Checked C with concolic testing to obtain an effective methodology for attaining safer C code. Checked C is a modern and backward compatible extension to the C programming language which provides facilities for writing memory-safe C code. We utilize incremental conversions of unsafe C software to Checked C. After each increment, we leverage concolic testing, an effective test generation technique, to support the conversion process by searching for newly introduced and existing bugs.Our RISC-V experiments using the RIOT Operating System (OS) demonstrate the effectiveness of our approach. We uncovered 4 previously unknown bugs and 3 bugs accidentally introduced through our conversion process.
NoVT: Eliminating C++ Virtual Calls to Mitigate Vtable Hijacking. 2021 IEEE European Symposium on Security and Privacy (EuroS P). :650—666.
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2021. The vast majority of nowadays remote code execution attacks target virtual function tables (vtables). Attackers hijack vtable pointers to change the control flow of a vulnerable program to their will, resulting in full control over the underlying system. In this paper, we present NoVT, a compiler-based defense against vtable hijacking. Instead of protecting vtables for virtual dispatch, our solution replaces them with switch-case constructs that are inherently control-flow safe, thus preserving control flow integrity of C++ virtual dispatch. NoVT extends Clang to perform a class hierarchy analysis on C++ source code. Instead of a vtable, each class gets unique identifier numbers which are used to dispatch the correct method implementation. Thereby, NoVT inherently protects all usages of a vtable, not just virtual dispatch. We evaluate NoVT on common benchmark applications and real-world programs including Chromium. Despite its strong security guarantees, NoVT improves runtime performance of most programs (mean overhead −0.5%, −3.7% min, 2% max). In addition, protected binaries are slightly smaller than unprotected ones. NoVT works on different CPU architectures and protects complex C++ programs against strong attacks like COOP and ShrinkWrap.
Research on Embedded Startup Method of Trusted Module. 2021 IEEE 5th Information Technology,Networking,Electronic and Automation Control Conference (ITNEC). 5:953—957.
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2021. In order to meet the requirements of secure start-up of embedded devices, this paper designs a secure and trusted circuit to realize the secure and trusted start-up of the system. This paper analyzes the principle and method of the circuit design, and verifies the preset information of the embedded device before the start of the embedded device, so as to ensure that the start process of the embedded device is carried out according to the predetermined way, and then uses the security module to measure the integrity of the data in the start process, so as to realize a trusted embedded system. The experimental results show that the security module has stronger security features and low latency. The integrity measurement is implemented in the trusted embedded system to realize the safe startup of embedded devices.
An Exploration of Microprocessor Self-Test Optimisation Based On Safe Faults. 2021 IEEE International Symposium on Defect and Fault Tolerance in VLSI and Nanotechnology Systems (DFT). :1—6.
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2021. Microprocessor software test libraries (STLs) must provide maximum fault coverage with minimum overhead. Pruning safe faults, which cannot cause errors in the output of the processor, from the fault list can increase fault coverage without adding test overhead. Applying more application-specific constraints can lead to the identification of more safe faults, and some such constraints are yet to be explored. This work explores the use of signal combination-based constraints alongside well-known constant signal-based constraints for identifying safe faults. Also, for the first time, information on safe faults is utilised during test compaction in order to further minimise test overhead. Results for an OpenRISC processor design show up to 2.33% improvement in fault coverage with the use of the proposed constraints. In one test program, a code segment contributing only to the coverage of safe faults is identified, with its removal providing a 1.09 % code size reduction on top of existing compaction techniques. The results may vary for a larger and more complex commercial design with greater scope for redundant logic. This work explores the use of signal combination-based constraints alongside well-known constant signal-based constraints for identifying safe faults. Also, for the first time, information on safe faults is utilised during test compaction in order to further minimise test overhead. Results for an OpenRISC processor design show up to 2.33% improvement in fault coverage with the use of the proposed constraints. In one test program, a code segment contributing only to the coverage of safe faults is identified, with its removal providing a 1.09 % code size reduction on top of existing compaction techniques. The results may vary for a larger and more complex commercial design with greater scope for redundant logic.
Source Code Analysis for Mobile Applications for Privacy Leaks. 2021 IEEE Madras Section Conference (MASCON). :1—6.
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2021. Intelligent gadgets for example smartphones, tablet phones, and personal digital assistants play an increasingly important part in our lives and have become indispensable in our everyday routines. As a result, the market for mobile apps tends to grow at a rapid rate, and mobile app utilization has long eclipsed that of desktop software. The applications based on these smartphones are becoming vulnerable due to the use of open-source operating systems in these smart devices. These applications are vulnerable to smartphones because of memory leaks; they can steal personal data, hack our smartphones, and monitor our private activity, giving anyone significant financial loss. Because of these issues, smartphone security plays a vital role in our daily lives. The Play Store contains unrated applications which any unprofessional developer can develop, and these applications do not pass through the rigorous process of testing and analysis of code leaks. The existing developed system does not include a stringent procedure to examine and investigate source code to detect such vulnerabilities among mobile applications. This paper presented a dynamic analysis-based robust system for Source Code Analysis of Mobile Applications for Privacy Leaks using a machine learning algorithm. Furthermore, our framework is called Source Code Analysis of Mobile Applications (SCA-MA), which combines DynaLog and our machine learning-based classifier for Source Code Analysis of Mobile Applications. Our dataset will contain around 20000 applications to test and analyze vulnerabilities. We will perform dynamic analysis and separate the classification of vulnerable applications and safe applications. Our results show that we can detect vulnerabilities through our proposed system while reviewing code and provide better results than other existing frameworks. We have evaluated our large dataset with the pervasive way so we can detect even small privacy leak which can harm our app. Finally, we have compared results with existing methods, and framework performance is better than other methods.
Vulnerability Exploiting SMS Push Notifications. 2021 16th Asia Joint Conference on Information Security (AsiaJCIS). :23—30.
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2021. SMS (Short Message Service)-based authentication is widely used as a simple and secure multi-factor authentication, where OTP (One Time Password) is sent to user’s mobile phone via SMS. However, SMS authentication is vulnerable to Password Reset Man in the Middle Attack (PRMitM). In this attack, the attacker makes a victim perform password reset OTP for sign-up verification OTP. If the victim enters OTP to a malicious man-in-the-middle site, the attacker can overtake the victim’s account.We find new smartphone useful functions may increase PR-MitM attack risks. SMS push notification informs us an arrival of message by showing only beginning of the message. Hence, those who received SMS OTP do not notice the cautionary notes and the name of the sender that are supposed to show below the code, which may lead to be compromised. Auto-fill function, which allow us to input authentication code with one touch, is also vulnerable for the same reason.In this study, we conduct a user study to investigate the effect of new smartphone functions incurring PRMitM attack.
Analysis of Innovative Rank of Batched Network Codes for Wireless Relay Networks. 2021 IEEE Information Theory Workshop (ITW). :1–6.
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2021. Wireless relay network is a solution for transmitting information from a source node to a sink node far away by installing a relay in between. The broadcasting nature of wireless communication allows the sink node to receive part of the data sent by the source node. In this way, the relay does not need to receive the whole piece of data from the source node and it does not need to forward everything it received. In this paper, we consider the application of batched network coding, a practical form of random linear network coding, for a better utilization of such a network. The amount of innovative information at the relay which is not yet received by the sink node, called the innovative rank, plays a crucial role in various applications including the design of the transmission scheme and the analysis of the throughput. We present a visualization of the innovative rank which allows us to understand and derive formulae related to the innovative rank with ease.
Towards Visual Analytics Dashboards for Provenance-driven Static Application Security Testing. 2021 IEEE Symposium on Visualization for Cyber Security (VizSec). :42–46.
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2021. The use of static code analysis tools for security audits can be time consuming, as the many existing tools focus on different aspects and therefore development teams often use several of these tools to keep code quality high and prevent security issues. Displaying the results of multiple tools, such as code smells and security warnings, in a unified interface can help developers get a better overview and prioritize upcoming work. We present visualizations and a dashboard that interactively display results from static code analysis for “interesting” commits during development. With this, we aim to provide an effective visual analytics tool for code security analysis results.
Investigating the Changes in Software Metrics after Vulnerability Is Fixed. 2021 IEEE International Conference on Big Data (Big Data). :5658–5663.
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2021. Preventing software vulnerabilities while writing code is one of the most effective ways for avoiding cyber attacks on any developed system. Although developers follow some standard guiding principles for ensuring secure code, the code can still have security bottlenecks and be compromised by an attacker. Therefore, assessing software security while developing code can help developers in writing vulnerability free code. Researchers have already focused on metrics-based and text mining based software vulnerability prediction models. The metrics based models showed higher precision in predicting vulnerabilities although the recall rate is low. In addition, current research did not investigate the impact of individual software metric on the occurrences of vulnerabilities. The main objective of this paper is to track the changes in every software metric after the developer fixes a particular vulnerability. The results of our research will potentially motivate further research on building more accurate vulnerability prediction models based on the appropriate software metrics. In particular, we have compared a total of 250 files from Apache Tomcat and Apache CXF. These files were extracted from the Apache database and were chosen because Apache released these files as vulnerable in their publicly available security advisories. Using a static analysis tool, metrics of the targeted vulnerable files and relevant fixed files (files where vulnerable code is removed by the developers) were extracted and compared. We show that eight of the 40 metrics have an average increase of 2% from vulnerable to fixed files. These metrics include CountDeclClass, CountDeclClassMethod, CountDeclClassVariable, CountDeclInstanceVariable, CountDeclMethodDefault, CountLineCode, MaxCyclomaticStrict, MaxNesting. This study will help developers to assess software security through utilizing software metrics in secure coding practices.
Formal Verification of 5G EAP-AKA Protocol. 2021 31st International Telecommunication Networks and Applications Conference (ITNAC). :140–146.
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2021. The advent of 5G, one of the most recent and promising technologies currently under deployment, fulfills the emerging needs of mobile subscribers by introducing several new technological advancements. However, this may lead to numerous attacks in the emerging 5G networks. Thus, to guarantee the secure transmission of user data, 5G Authentication protocols such as Extensible Authentication Protocol - Authenticated Key Agreement Protocol (EAP-AKA) were developed. These protocols play an important role in ensuring security to the users as well as their data. However, there exists no guarantees about the security of the protocols. Thus formal verification is necessary to ensure that the authentication protocols are devoid of vulnerabilities or security loopholes. Towards this goal, we formally verify the security of the 5G EAP-AKA protocol using an automated verification tool called ProVerif. ProVerif identifies traces of attacks and checks for security loopholes that can be accessed by the attackers. In addition, we model the complete architecture of the 5G EAP-AKA protocol using the language called typed pi-calculus and analyze the protocol architecture through symbolic model checking. Our analysis shows that some cryptographic parameters in the architecture can be accessed by the attackers which cause the corresponding security properties to be violated.
VM Migration Scheduling as Moving Target Defense against Memory DoS Attacks: An Empirical Study. 2021 IEEE Symposium on Computers and Communications (ISCC). :1—6.
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2021. Memory Denial of Service (DoS) attacks are easy-to-launch, hard to detect, and significantly impact their targets. In memory DoS, the attacker targets the memory of his Virtual Machine (VM) and, due to hardware isolation issues, the attack affects the co-resident VMs. Theoretically, we can deploy VM migration as Moving Target Defense (MTD) against memory DoS. However, the current literature lacks empirical evidence supporting this hypothesis. Moreover, there is a need to evaluate how the VM migration timing impacts the potential MTD protection. This practical experience report presents an experiment on VM migration-based MTD against memory DoS. We evaluate the impact of memory DoS attacks in the context of two applications running in co-hosted VMs: machine learning and OLTP. The results highlight that the memory DoS attacks lead to more than 70% reduction in the applications' performance. Nevertheless, timely VM migrations can significantly mitigate the attack effects in both considered applications.
Developing Computer Applications without any OS or Kernel in a Multi-core Architecture. 2021 International Symposium on Networks, Computers and Communications (ISNCC). :1—8.
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2021. Over the years, operating systems (OSs) have grown significantly in complexity and size providing attackers with more avenues to compromise their security. By eliminating the OS, it becomes possible to develop general-purpose non-embedded applications that are free of typical OS-related vulnerabilities. Such applications are simpler and smaller in size, making it easier secure the application code. Bare machine computing (BMC) applications run on ordinary desktops and laptops without the support of any operating system or centralized kernel. Many BMC applications have been developed previously for single-core systems. We show how to build BMC applications for multicore systems by presenting the design and implementation of a novel UDP-based bare machine prototype Web server for a multicore architecture. We also include preliminary experimental results from running the server on the Internet. This work provides a foundation for building secure computer applications that run on multicore systems without the need for intermediary software.
Performance Portability of an SpMV Kernel Across Scientific Computing and Data Science Applications. 2021 IEEE High Performance Extreme Computing Conference (HPEC). :1—8.
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2021. Both the data science and scientific computing communities are embracing GPU acceleration for their most demanding workloads. For scientific computing applications, the massive volume of code and diversity of hardware platforms at supercomputing centers has motivated a strong effort toward performance portability. This property of a program, denoting its ability to perform well on multiple architectures and varied datasets, is heavily dependent on the choice of parallel programming model and which features of the programming model are used. In this paper, we evaluate performance portability in the context of a data science workload in contrast to a scientific computing workload, evaluating the same sparse matrix kernel on both. Among our implementations of the kernel in different performance-portable programming models, we find that many struggle to consistently achieve performance improvements using the GPU compared to simple one-line OpenMP parallelization on high-end multicore CPUs. We show one that does, and its performance approaches and sometimes even matches that of vendor-provided GPU math libraries.
Twine Stack: A Hybrid Mechanism Achieving Less Cost for Return Address Protection. 2021 IEEE 30th Asian Test Symposium (ATS). :7—12.
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2021. Return-oriented programming(ROP) is a prevalent technique that targets return addresses to hijack control flow. To prevent such attack, researchers mainly focus on either Shadow Stack or MAC-based mechanisms(message code authentication). But Shadow Stack suffers from additional memory overhead and information leakage, while MAC-based mechanisms(e.g. Zipper Stack) impose high runtime overhead for MAC calculations.In this paper, we propose Twine Stack, a hybrid and efficient return address protection mechanism with lightweight hardware extension. It utilizes a tiny hardware shadow stack to realize a new multi-chain Zipper Stack. Specifically, each entry in the shadow stack stores a return address and its MAC in each chain, allowing queueing calculation with just one hash module. At meantime, some return address verifications could be done by comparison with the hardware shadow stack, instead of calculation again. We implemented Twine Stack on RISC-V architecture, and evaluated it on FPGA board. Our experiments show that Twine Stack reduces over 95% hash verifications, and imposes merely 1.38% performance overhead with an area overhead of 974 LUTs and 726 flip flops. The result demonstrates that our hybrid scheme mitigates the drawbacks of each separate scheme.
Incremental code updates exploitation as a basis for return oriented programming attacks on resource-constrained devices. 2021 5th Cyber Security in Networking Conference (CSNet). :55—62.
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2021. Code-reuse attacks pose a threat to embedded devices since they are able to defeat common security defenses such as non-executable stacks. To succeed in his code-reuse attack, the attacker has to gain knowledge of some or all of the instructions of the target firmware/software. In case of a bare-metal firmware that is protected from being dumped out of a device, it is hard to know the running instructions of the target firmware. This consequently makes code-reuse attacks more difficult to achieve. This paper shows how an attacker can gain knowledge of some of these instructions by sniffing the unencrypted incremental updates. These updates exist to reduce the radio reception power for resource-constrained devices. Based on the literature, these updates are checked against authentication and integrity, but they are sometimes sent unencrypted. Therefore, it will be demonstrated how a Return-Oriented Programming (ROP) attack can be accomplished using only the passively sniffed incremental updates. The generated updates of the R3diff and Delta Generator (DG) differencing algorithms will be under assessment. The evaluation reveals that both of them can be exploited by the attacker. It also shows that the DG generated updates leak more information than the R3diff generated updates. To defend against this attack, different countermeasures that consider different power consumption scenarios are proposed, but yet to be evaluated.
Benchmarking Robustness of Deep Learning Classifiers Using Two-Factor Perturbation. 2021 IEEE International Conference on Big Data (Big Data). :5085–5094.
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2021. Deep learning (DL) classifiers are often unstable in that they may change significantly when retested on perturbed images or low quality images. This paper adds to the fundamental body of work on the robustness of DL classifiers. We introduce a new two-dimensional benchmarking matrix to evaluate robustness of DL classifiers, and we also innovate a four-quadrant statistical visualization tool, including minimum accuracy, maximum accuracy, mean accuracy, and coefficient of variation, for benchmarking robustness of DL classifiers. To measure robust DL classifiers, we create comprehensive 69 benchmarking image sets, including a clean set, sets with single factor perturbations, and sets with two-factor perturbation conditions. After collecting experimental results, we first report that using two-factor perturbed images improves both robustness and accuracy of DL classifiers. The two-factor perturbation includes (1) two digital perturbations (salt & pepper noise and Gaussian noise) applied in both sequences, and (2) one digital perturbation (salt & pepper noise) and a geometric perturbation (rotation) applied in both sequences. All source codes, related image sets, and results are shared on the GitHub website at https://github.com/caperock/robustai to support future academic research and industry projects.
Measuring source code conciseness across programming languages using compression. 2021 IEEE 21st International Working Conference on Source Code Analysis and Manipulation (SCAM). :47–57.
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2021. It is well-known, and often a topic of heated debates, that programs in some programming languages are more concise than in others. This is a relevant factor when comparing or aggregating volume-impacted metrics on source code written in a combination of programming languages. In this paper, we present a model for measuring the conciseness of programming languages in a consistent, objective and evidence-based way. We present the approach, explain how it is founded on information theoretical principles, present detailed analysis steps and show the quantitative results of applying this model to a large benchmark of diverse commercial software applications. We demonstrate that our metric for language conciseness is strongly correlated with both an alternative analytical approach, and with a large scale developer survey, and show how its results can be applied to improve software metrics for multi-language applications.
AngErza: Automated Exploit Generation. 2021 12th International Conference on Computing Communication and Networking Technologies (ICCCNT). :1—6.
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2021. Vulnerability detection and exploitation serves as a milestone for secure development and identifying major threats in software applications. Automated exploit generation helps in easier identification of bugs, the attack vectors and the various possibilities of generation of the exploit payload. Thus, we introduce AngErza which uses dynamic and symbolic execution to identify hot-spots in the code, formulate constraints and generate a payload based on those constraints. Our tool is entirely based on angr which is an open-sourced offensive binary analysis framework. The work around AngErza focuses on exploit and vulnerability detection in CTF-style C binaries compiled on 64-bit Intel architecture for the early-phase of this project.
Structure-Aware Hierarchical Graph Pooling using Information Bottleneck. 2021 International Joint Conference on Neural Networks (IJCNN). :1–8.
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2021. Graph pooling is an essential ingredient of Graph Neural Networks (GNNs) in graph classification and regression tasks. For these tasks, different pooling strategies have been proposed to generate a graph-level representation by downsampling and summarizing nodes' features in a graph. However, most existing pooling methods are unable to capture distinguishable structural information effectively. Besides, they are prone to adversarial attacks. In this work, we propose a novel pooling method named as HIBPool where we leverage the Information Bottleneck (IB) principle that optimally balances the expressiveness and robustness of a model to learn representations of input data. Furthermore, we introduce a novel structure-aware Discriminative Pooling Readout (DiP-Readout) function to capture the informative local subgraph structures in the graph. Finally, our experimental results show that our model significantly outperforms other state-of-art methods on several graph classification benchmarks and more resilient to feature-perturbation attack than existing pooling methods11Source code at: https://github.com/forkkr/HIBPool.
Prevent Data Exfiltration on Smart Phones Using Audio Distortion and Machine Learning. 2021 Moratuwa Engineering Research Conference (MERCon). :345–350.
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2021. Attacks on mobile devices have gained a significant amount of attention lately. This is because more and more individuals are switching to smartphones from traditional non-smartphones. Therefore, attackers or cybercriminals are now getting on the bandwagon to have an opportunity at obtaining information stored on smartphones. In this paper, we present an Android mobile application that will aid to minimize data exfiltration from attacks, such as, Acoustic Side-Channel Attack, Clipboard Jacking, Permission Misuse and Malicious Apps. This paper will commence its inception with an introduction explaining the current issues in general and how attacks such as side-channel attacks and clipboard jacking paved the way for data exfiltration. We will also discuss a few already existing solutions that try to mitigate these problems. Moving on to the methodology we will emphasize how we came about the solution and what methods we followed to achieve the end goal of securing the smartphone. In the final section, we will discuss the outcomes of the project and conclude what needs to be done in the future to enhance this project so that this mobile application will continue to keep the user's data safe from the criminals' grasps.
An Information Theoretic Approach to Assist in Identifying Counterfeit Consumer Goods. 2021 IEEE AFRICON. :1–6.
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2021. In an increasingly connected world where products are just a click away, there is a growing need for systems that seek to equip consumers with the necessary tools to identify misrepresented products. Sub-standard ingredients used in the production of sanitary towels can pose a serious health risk to the consumer. Informal retailers or Spaza-shops have been accused of selling counterfeit food products to unsuspecting consumers. In this paper, we propose a system that can be used by consumers to scan a quick response (QR) code printed on the product. Built into an android application, is a system that applies the RSA public key encryption algorithm to secure the data prior to encoding into the QR code. The proposed system is also responsible for updating location data of previous scans on a dedicated cloud database. Upon completion of a field test, having collected months of consumer data, counterfeit prediction can be improved. In addition, a timely warning can be sent to a customer and relevant authorities if a unique product batch number is scanned outside of an expected area.
Performance Analysis of Zero-Trust Multi-Cloud. 2021 IEEE 14th International Conference on Cloud Computing (CLOUD). :730–732.
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2021. Zero Trust security model permits to secure cloud native applications while encrypting all network communication, authenticating, and authorizing every request. The service mesh can enable Zero Trust using a side-car proxy without changes to the application code. To the best of our knowledge, no previous work has provided a performance analysis of Zero Trust in a multi-cloud environment. This paper proposes a multi-cloud framework and a testing workflow to analyse performance of the data plane under load and the impact on the control plane, when Zero Trust is enabled. The results of preliminary tests show that Istio has reduced latency variability in responding to sequential HTTP requests. Results also reveal that the overall CPU and memory usage can increase based on service mesh configuration and the cloud environment.
Adopting Trusted Types in ProductionWeb Frameworks to Prevent DOM-Based Cross-Site Scripting: A Case Study. 2021 IEEE European Symposium on Security and Privacy Workshops (EuroS PW). :60–73.
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2021. Cross-site scripting (XSS) is a common security vulnerability found in web applications. DOM-based XSS, one of the variants, is becoming particularly more prevalent with the boom of single-page applications where most of the UI changes are achieved by modifying the DOM through in-browser scripting. It is very easy for developers to introduce XSS vulnerabilities into web applications since there are many ways for user-controlled, unsanitized input to flow into a Web API and get interpreted as HTML markup and JavaScript code. An emerging Web API proposal called Trusted Types aims to prevent DOM XSS by making Web APIs secure by default. Different from other XSS mitigations that mostly focus on post-development protection, Trusted Types direct developers to write XSS-free code in the first place. A common concern when adopting a new security mechanism is how much effort is required to refactor existing code bases. In this paper, we report a case study on adopting Trusted Types in a well-established web framework. Our experience can help the web community better understand the benefits of making web applications compatible with Trusted Types, while also getting to know the related challenges and resolutions. We focused our work on Angular, which is one of the most popular web development frameworks available on the market.
Identifying Vulnerable IoT Applications Using Deep Learning. 2020 IEEE 27th International Conference on Software Analysis, Evolution and Reengineering (SANER). :582–586.
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2020. This paper presents an approach for the identification of vulnerable IoT applications using deep learning algorithms. The approach focuses on a category of vulnerabilities that leads to sensitive information leakage which can be identified using taint flow analysis. First, we analyze the source code of IoT apps in order to recover tokens along their frequencies and tainted flows. Second, we develop, Token2Vec, which transforms the source code tokens into vectors. We have also developed Flow2Vec, which transforms the identified tainted flows into vectors. Third, we use the recovered vectors to train a deep learning algorithm to build a model for the identification of tainted apps. We have evaluated the approach on two datasets and the experiments show that the proposed approach of combining tainted flows features with the base benchmark that uses token frequencies only, has improved the accuracy of the prediction models from 77.78% to 92.59% for Corpus1 and 61.11% to 87.03% for Corpus2.
Highly Secured all Optical DIM Codes using AND Gate. 2020 Indo – Taiwan 2nd International Conference on Computing, Analytics and Networks (Indo-Taiwan ICAN). :64—68.
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2020. Optical Code Division Multiple Access (OCDMA) is an inevitable innovation to cope up with the impediments of regularly expanding information traffic and numerous user accesses in optical systems. In Spectral Amplitude Coding (SAC)-OCDMA systems cross correlation and Multiple Access Interference (MAI) are utmost concerns. For eliminating the cross correlation, reducing the MAI and to enhance the security, in this work, all optical Diagonal Identity Matrices codes (DIM) with Zero Cross-Correlation (ZCC) and optical gating are presented. Chip rate of the proposed work is 0.03 ns and total 60 users are considered with semiconductor optical amplifier based AND operation. Effects of optical gating are analyzed in the presence/absence of eavesdropper in terms of Q factor and received extinction ratio. Proposed system has advantages for service provider because this is mapping free technique and can be easily designed for large number of users.