Biblio

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2015-04-30
Miller, Andrew, Hicks, Michael, Katz, Jonathan, Shi, Elaine.  2014.  Authenticated Data Structures, Generically. SIGPLAN Not.. 49:411–423.

An authenticated data structure (ADS) is a data structure whose operations can be carried out by an untrusted prover, the results of which a verifier can efficiently check as authentic. This is done by having the prover produce a compact proof that the verifier can check along with each operation's result. ADSs thus support outsourcing data maintenance and processing tasks to untrusted servers without loss of integrity. Past work on ADSs has focused on particular data structures (or limited classes of data structures), one at a time, often with support only for particular operations.

This paper presents a generic method, using a simple extension to a ML-like functional programming language we call λ• (lambda-auth), with which one can program authenticated operations over any data structure defined by standard type constructors, including recursive types, sums, and products. The programmer writes the data structure largely as usual and it is compiled to code to be run by the prover and verifier. Using a formalization of λ• we prove that all well-typed λ• programs result in code that is secure under the standard cryptographic assumption of collision-resistant hash functions. We have implemented λ• as an extension to the OCaml compiler, and have used it to produce authenticated versions of many interesting data structures including binary search trees, red-black+ trees, skip lists, and more. Performance experiments show that our approach is efficient, giving up little compared to the hand-optimized data structures developed previously.

Girma, Anteneh, Garuba, Moses, Goel, Rojini.  2014.  Cloud Computing Vulnerability: DDoS As Its Main Security Threat, and Analysis of IDS As a Solution Model. Proceedings of the 2014 11th International Conference on Information Technology: New Generations. :307–312.

Cloud computing has emerged as an increasingly popular means of delivering IT-enabled business services and a potential technology resource choice for many private and government organizations in today's rapidly changing computing environment. Consequently, as cloud computing technology, functionality and usability expands unique security vulnerabilities and treats requiring timely attention arise continuously. The primary challenge being providing continuous service availability. This paper will address cloud security vulnerability issues, the threats propagated by a distributed denial of service (DDOS) attack on cloud computing infrastructure and also discuss the means and techniques that could detect and prevent the attacks.

2015-05-01
Dua, Akshay, Bulusu, Nirupama, Feng, Wu-Chang, Hu, Wen.  2014.  Combating Software and Sybil Attacks to Data Integrity in Crowd-Sourced Embedded Systems. ACM Trans. Embed. Comput. Syst.. 13:154:1–154:19.

Crowd-sourced mobile embedded systems allow people to contribute sensor data, for critical applications, including transportation, emergency response and eHealth. Data integrity becomes imperative as malicious participants can launch software and Sybil attacks modifying the sensing platform and data. To address these attacks, we develop (1) a Trusted Sensing Peripheral (TSP) enabling collection of high-integrity raw or aggregated data, and participation in applications requiring additional modalities; and (2) a Secure Tasking and Aggregation Protocol (STAP) enabling aggregation of TSP trusted readings by untrusted intermediaries, while efficiently detecting fabricators. Evaluations demonstrate that TSP and STAP are practical and energy-efficient.

2015-05-06
Ceccarelli, A., Montecchi, L., Brancati, F., Lollini, P., Marguglio, A., Bondavalli, A..  2014.  Continuous and Transparent User Identity Verification for Secure Internet Services. Dependable and Secure Computing, IEEE Transactions on. PP:1-1.

Session management in distributed Internet services is traditionally based on username and password, explicit logouts and mechanisms of user session expiration using classic timeouts. Emerging biometric solutions allow substituting username and password with biometric data during session establishment, but in such an approach still a single verification is deemed sufficient, and the identity of a user is considered immutable during the entire session. Additionally, the length of the session timeout may impact on the usability of the service and consequent client satisfaction. This paper explores promising alternatives offered by applying biometrics in the management of sessions. A secure protocol is defined for perpetual authentication through continuous user verification. The protocol determines adaptive timeouts based on the quality, frequency and type of biometric data transparently acquired from the user. The functional behavior of the protocol is illustrated through Matlab simulations, while model-based quantitative analysis is carried out to assess the ability of the protocol to contrast security attacks exercised by different kinds of attackers. Finally, the current prototype for PCs and Android smartphones is discussed.
 

Salah, Khaled.  2014.  Harnessing the Cloud for Teaching Cybersecurity. Proceedings of the 45th ACM Technical Symposium on Computer Science Education. :529–534.

Cloud computing has become an attractive paradigm for many organizations in government, industry as well as academia. In academia, the cloud can offer instructors and students (whether local or at a distance) on-demand, dedicated, isolated, unlimited, and easily configurable machines. Such an approach has clear advantages over access to machines in a classic lab setting. In this paper, we show how cloud services and infrastructure could be harnessed to facilitate practical experience and training for cybersecurity. We used the popular Amazon Web Services (AWS) cloud; however, the use cases and approaches laid out in this paper are also applicable to other cloud providers.

2014-09-17
Layman, Lucas, Diffo, Sylvain David, Zazworka, Nico.  2014.  Human Factors in Webserver Log File Analysis: A Controlled Experiment on Investigating Malicious Activity. Proceedings of the 2014 Symposium and Bootcamp on the Science of Security. :9:1–9:11.

While automated methods are the first line of defense for detecting attacks on webservers, a human agent is required to understand the attacker's intent and the attack process. The goal of this research is to understand the value of various log fields and the cognitive processes by which log information is grouped, searched, and correlated. Such knowledge will enable the development of human-focused log file investigation technologies. We performed controlled experiments with 65 subjects (IT professionals and novices) who investigated excerpts from six webserver log files. Quantitative and qualitative data were gathered to: 1) analyze subject accuracy in identifying malicious activity; 2) identify the most useful pieces of log file information; and 3) understand the techniques and strategies used by subjects to process the information. Statistically significant effects were observed in the accuracy of identifying attacks and time taken depending on the type of attack. Systematic differences were also observed in the log fields used by high-performing and low-performing groups. The findings include: 1) new insights into how specific log data fields are used to effectively assess potentially malicious activity; 2) obfuscating factors in log data from a human cognitive perspective; and 3) practical implications for tools to support log file investigations.

Rao, Ashwini, Hibshi, Hanan, Breaux, Travis, Lehker, Jean-Michel, Niu, Jianwei.  2014.  Less is More?: Investigating the Role of Examples in Security Studies Using Analogical Transfer Proceedings of the 2014 Symposium and Bootcamp on the Science of Security. :7:1–7:12.

Information system developers and administrators often overlook critical security requirements and best practices. This may be due to lack of tools and techniques that allow practitioners to tailor security knowledge to their particular context. In order to explore the impact of new security methods, we must improve our ability to study the impact of security tools and methods on software and system development. In this paper, we present early findings of an experiment to assess the extent to which the number and type of examples used in security training stimuli can impact security problem solving. To motivate this research, we formulate hypotheses from analogical transfer theory in psychology. The independent variables include number of problem surfaces and schemas, and the dependent variable is the answer accuracy. Our study results do not show a statistically significant difference in performance when the number and types of examples are varied. We discuss the limitations, threats to validity and opportunities for future studies in this area.

Liu, Qian, Bae, Juhee, Watson, Benjamin, McLaughhlin, Anne, Enck, William.  2014.  Modeling and Sensing Risky User Behavior on Mobile Devices. Proceedings of the 2014 Symposium and Bootcamp on the Science of Security. :33:1–33:2.

As mobile technology begins to dominate computing, understanding how their use impacts security becomes increasingly important. Fortunately, this challenge is also an opportunity: the rich set of sensors with which most mobile devices are equipped provide a rich contextual dataset, one that should enable mobile user behavior to be modeled well enough to predict when users are likely to act insecurely, and provide cognitively grounded explanations of those behaviors. We will evaluate this hypothesis with a series of experiments designed first to confirm that mobile sensor data can reliably predict user stress, and that users experiencing such stress are more likely to act insecurely.

2018-05-25
Hei, Xiali, Lin, Shan.  2014.  Multi-part File Encryption for Electronic Health Records Cloud. Proceedings of the 4th ACM MobiHoc Workshop on Pervasive Wireless Healthcare. :31–36.
2014-10-24
Hibshi, Hanan, Slavin, Rocky, Niu, Jianwei, Breaux, Travis D.  2014.  Rethinking Security Requirements in RE Research.

As information security became an increasing concern for software developers and users, requirements engineering (RE) researchers brought new insight to security requirements. Security requirements aim to address security at the early stages of system design while accommodating the complex needs of different stakeholders. Meanwhile, other research communities, such as usable privacy and security, have also examined these requirements with specialized goal to make security more usable for stakeholders from product owners, to system users and administrators. In this paper we report results from conducting a literature survey to compare security requirements research from RE Conferences with the Symposium on Usable Privacy and Security (SOUPS). We report similarities between the two research areas, such as common goals, technical definitions, research problems, and directions. Further, we clarify the differences between these two communities to understand how they can leverage each other’s insights. From our analysis, we recommend new directions in security requirements research mainly to expand the meaning of security requirements in RE to reflect the technological advancements that the broader field of security is experiencing. These recommendations to encourage cross- collaboration with other communities are not limited to the security requirements area; in fact, we believe they can be generalized to other areas of RE. 

2015-05-06
Odelu, Vanga, Das, Ashok Kumar, Goswami, Adrijit.  2014.  A Secure Effective Key Management Scheme for Dynamic Access Control in a Large Leaf Class Hierarchy. Inf. Sci.. 269:270–285.

Lo et al. (2011) proposed an efficient key assignment scheme for access control in a large leaf class hierarchy where the alternations in leaf classes are more frequent than in non-leaf classes in the hierarchy. Their scheme is based on the public-key cryptosystem and hash function where operations like modular exponentiations are very much costly compared to symmetric-key encryptions and decryptions, and hash computations. Their scheme performs better than the previously proposed schemes. However, in this paper, we show that Lo et al.’s scheme fails to preserve the forward security property where a security class can also derive the secret keys of its successor classes ’s even after deleting the security class  from the hierarchy. We aim to propose a new key management scheme for dynamic access control in a large leaf class hierarchy, which makes use of symmetric-key cryptosystem and one-way hash function. We show that our scheme requires significantly less storage and computational overheads as compared to Lo et al.’s scheme and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against all possible attacks including the forward security. In addition, our scheme supports efficiently dynamic access control problems compared to Lo et al.’s scheme and other related schemes. Thus, higher security along with low storage and computational costs make our scheme more suitable for practical applications compared to other schemes.

2014-09-17
Yu, Xianqing, Ning, Peng, Vouk, Mladen A..  2014.  Securing Hadoop in Cloud. Proceedings of the 2014 Symposium and Bootcamp on the Science of Security. :26:1–26:2.

Hadoop is a map-reduce implementation that rapidly processes data in parallel. Cloud provides reliability, flexibility, scalability, elasticity and cost saving to customers. Moving Hadoop into Cloud can be beneficial to Hadoop users. However, Hadoop has two vulnerabilities that can dramatically impact its security in a Cloud. The vulnerabilities are its overloaded authentication key, and the lack of fine-grained access control at the data access level. We propose and develop a security enhancement for Cloud-based Hadoop.

2020-01-21
Azimi, Mahdi, Sami, Ashkan, Khalili, Abdullah.  2014.  A Security Test-Bed for Industrial Control Systems. Proceedings of the 1st International Workshop on Modern Software Engineering Methods for Industrial Automation. :26–31.

Industrial Control Systems (ICS) such as Supervisory Control And Data Acquisition (SCADA), Distributed Control Systems (DCS) and Distributed Automation Systems (DAS) control and monitor critical infrastructures. In recent years, proliferation of cyber-attacks to ICS revealed that a large number of security vulnerabilities exist in such systems. Excessive security solutions are proposed to remove the vulnerabilities and improve the security of ICS. However, to the best of our knowledge, none of them presented or developed a security test-bed which is vital to evaluate the security of ICS tools and products. In this paper, a test-bed is proposed for evaluating the security of industrial applications by providing different metrics for static testing, dynamic testing and network testing in industrial settings. Using these metrics and results of the three tests, industrial applications can be compared with each other from security point of view. Experimental results on several real world applications indicate that proposed test-bed can be successfully employed to evaluate and compare the security level of industrial applications.

2015-04-30
Chiang, R., Rajasekaran, S., Zhang, N., Huang, H..  2014.  Swiper: Exploiting Virtual Machine Vulnerability in Third-Party Clouds with Competition for I/O Resources. Parallel and Distributed Systems, IEEE Transactions on. PP:1-1.

The emerging paradigm of cloud computing, e.g., Amazon Elastic Compute Cloud (EC2), promises a highly flexible yet robust environment for large-scale applications. Ideally, while multiple virtual machines (VM) share the same physical resources (e.g., CPUs, caches, DRAM, and I/O devices), each application should be allocated to an independently managed VM and isolated from one another. Unfortunately, the absence of physical isolation inevitably opens doors to a number of security threats. In this paper, we demonstrate in EC2 a new type of security vulnerability caused by competition between virtual I/O workloads-i.e., by leveraging the competition for shared resources, an adversary could intentionally slow down the execution of a targeted application in a VM that shares the same hardware. In particular, we focus on I/O resources such as hard-drive throughput and/or network bandwidth-which are critical for data-intensive applications. We design and implement Swiper, a framework which uses a carefully designed workload to incur significant delays on the targeted application and VM with minimum cost (i.e., resource consumption). We conduct a comprehensive set of experiments in EC2, which clearly demonstrates that Swiper is capable of significantly slowing down various server applications while consuming a small amount of resources.

2015-05-06
McGettrick, Andrew, Cassel, Lillian N., Dark, Melissa, Hawthorne, Elizabeth K., Impagliazzo, John.  2014.  Toward Curricular Guidelines for Cybersecurity. Proceedings of the 45th ACM Technical Symposium on Computer Science Education. :81–82.

This session reports on a workshop convened by the ACM Education Board with funding by the US National Science Foundation and invites discussion from the community on the workshop findings. The topic, curricular directions for cybersecurity, is one that resonates in many departments considering how best to prepare graduates to face the challenges of security issues in employment and future research. The session will include presentation of the workshop context and conclusions, but will be open to participant discussion. This will be the first public presentation of the results of the workshop and the first opportunity for significant response.

2015-05-05
SHAR, L., Briand, L., Tan, H..  2014.  Web Application Vulnerability Prediction using Hybrid Program Analysis and Machine Learning. Dependable and Secure Computing, IEEE Transactions on. PP:1-1.

Due to limited time and resources, web software engineers need support in identifying vulnerable code. A practical approach to predicting vulnerable code would enable them to prioritize security auditing efforts. In this paper, we propose using a set of hybrid (static+dynamic) code attributes that characterize input validation and input sanitization code patterns and are expected to be significant indicators of web application vulnerabilities. Because static and dynamic program analyses complement each other, both techniques are used to extract the proposed attributes in an accurate and scalable way. Current vulnerability prediction techniques rely on the availability of data labeled with vulnerability information for training. For many real world applications, past vulnerability data is often not available or at least not complete. Hence, to address both situations where labeled past data is fully available or not, we apply both supervised and semi-supervised learning when building vulnerability predictors based on hybrid code attributes. Given that semi-supervised learning is entirely unexplored in this domain, we describe how to use this learning scheme effectively for vulnerability prediction. We performed empirical case studies on seven open source projects where we built and evaluated supervised and semi-supervised models. When cross validated with fully available labeled data, the supervised models achieve an average of 77 percent recall and 5 percent probability of false alarm for predicting SQL injection, cross site scripting, remote code execution and file inclusion vulnerabilities. With a low amount of labeled data, when compared to the supervised model, the semi-supervised model showed an average improvement of 24 percent higher recall and 3 percent lower probability of false alarm, thus suggesting semi-supervised learning may be a preferable solution for many real world applications where vulnerability data is missing.
 

2016-12-05
Eric Yuan, Naeem Esfahani, Sam Malek.  2014.  A Systematic Survey of Self-Protecting Software Systems. ACM Transactions on Autonomous and Adaptive Systems (TAAS) - Special Section on Best Papers from SEAMS 2012 . 8(4)

Self-protecting software systems are a class of autonomic systems capable of detecting and mitigating security threats at runtime. They are growing in importance, as the stovepipe static methods of securing software systems have been shown to be inadequate for the challenges posed by modern software systems. Self-protection, like other self-* properties, allows the system to adapt to the changing environment through autonomic means without much human intervention, and can thereby be responsive, agile, and cost effective. While existing research has made significant progress towards autonomic and adaptive security, gaps and challenges remain. This article presents a significant extension of our preliminary study in this area. In particular, unlike our preliminary study, here we have followed a systematic literature review process, which has broadened the scope of our study and strengthened the validity of our conclusions. By proposing and applying a comprehensive taxonomy to classify and characterize the state-of-the-art research in this area, we have identified key patterns, trends and challenges in the existing approaches, which reveals a number of opportunities that will shape the focus of future research efforts.

2015-01-13
John Slankas, Maria Riaz, Jason King, Laurie Williams.  2014.  Discovering Security Requirements from Natural Language. 36th International Conference on Software Engineering.

Project documentation often contains security-relevant statements that are indicative of the security requirements of a system. However these statements may not be explicitly specified or straightforward to locate. At best, requirements analysts manually extract applicable security requirements from project documents. However, security requirements that are not explicitly stated may not be considered during implementation. The goal of this research is to aid requirements analysts in generating security requirements through identifying securityrelevant statements in project documentation and providing context-specific templates to generate security requirements. First, we identify the most prevalent security objectives from software security literature. To identify security-relevant statements in project documentation, we propose a tool-based process to classify statements as related to zero or more security objectives. We then develop a set of context-specific templates to help translate the security objectives of each statement into explicit sets of security functional requirements. We evaluate our process on six documents from the electronic healthcare software industry, identifying 46% of statements as implicitly or explicitly related to security. Our classification approach identified security objectives with a precision of .82 and recall of .79. From our total set of classified statements, we extracted 16 context-specific templates that identify 41 reusable security requirements.

2016-12-05
Hanan Hibshi, Travis Breaux, Maria Riaz, Laurie Williams.  2014.  A Framework to Measure Experts' Decision Making in Security Requirements Analysis. 2014 IEEE 1st International Workshop on Evolving Security and Privacy Requirements Engineering (ESPRE).

Research shows that commonly accepted security requirements   are  not  generally  applied  in  practice.  Instead  of relying on requirements checklists, security experts rely on their expertise and background knowledge to identify security vulnerabilities.  To  understand  the  gap  between  available checklists  and  practice,  we  conducted  a  series  of  interviews  to encode   the   decision-making   process   of  security   experts   and novices during security requirements analysis. Participants were asked to analyze two types of artifacts: source code, and network diagrams  for  vulnerabilities  and  to  apply  a  requirements checklist to mitigate some of those vulnerabilities.  We framed our study using Situation Awareness—a cognitive theory from psychology—to   elicit  responses   that  we  later  analyzed   using coding theory and grounded analysis.  We report our preliminary results of analyzing two interviews that reveal possible decision- making patterns that could characterize how analysts perceive, comprehend   and  project  future  threats  which  leads  them  to decide upon requirements  and their specifications,  in addition, to how  experts  use  assumptions  to  overcome  ambiguity  in specifications.  Our goal is to build a model that researchers  can use to evaluate their security requirements methods against how experts transition through different situation awareness levels in their decision-making  process.

2015-05-04
Vijayan, A., Thomas, T..  2014.  Anonymity, unlinkability and unobservability in mobile ad hoc networks. Communications and Signal Processing (ICCSP), 2014 International Conference on. :1880-1884.

Mobile ad hoc networks have the features of open medium, dynamic topology, cooperative algorithms, lack of centralized monitoring etc. Due to these, mobile ad hoc networks are much vulnerable to security attacks when compared to wired networks. There are various routing protocols that have been developed to cope up with the limitations imposed by the ad hoc networks. But none of these routing schemes provide complete unlinkability and unobservability. In this paper we have done a survey about anonymous routing and secure communications in mobile ad hoc networks. Different routing protocols are analyzed based on public/private key pairs and cryptosystems, within that USOR can well protect user privacy against both inside and outside attackers. It is a combination of group signature scheme and ID based encryption scheme. These are run during the route discovery process. We implement USOR on ns2, and then its performance is compared with AODV.

Shahare, P.C., Chavhan, N.A..  2014.  An Approach to Secure Sink Node's Location Privacy in Wireless Sensor Networks. Communication Systems and Network Technologies (CSNT), 2014 Fourth International Conference on. :748-751.

Wireless Sensor Network has a wide range of applications including environmental monitoring and data gathering in hostile environments. This kind of network is easily leaned to different external and internal attacks because of its open nature. Sink node is a receiving and collection point that gathers data from the sensor nodes present in the network. Thus, it forms bridge between sensors and the user. A complete sensor network can be made useless if this sink node is attacked. To ensure continuous usage, it is very important to preserve the location privacy of sink nodes. A very good approach for securing location privacy of sink node is proposed in this paper. The proposed scheme tries to modify the traditional Blast technique by adding shortest path algorithm and an efficient clustering mechanism in the network and tries to minimize the energy consumption and packet delay.

2015-05-06
Khobragade, P.K., Malik, L.G..  2014.  Data Generation and Analysis for Digital Forensic Application Using Data Mining. Communication Systems and Network Technologies (CSNT), 2014 Fourth International Conference on. :458-462.

In the cyber crime huge log data, transactional data occurs which tends to plenty of data for storage and analyze them. It is difficult for forensic investigators to play plenty of time to find out clue and analyze those data. In network forensic analysis involves network traces and detection of attacks. The trace involves an Intrusion Detection System and firewall logs, logs generated by network services and applications, packet captures by sniffers. In network lots of data is generated in every event of action, so it is difficult for forensic investigators to find out clue and analyzing those data. In network forensics is deals with analysis, monitoring, capturing, recording, and analysis of network traffic for detecting intrusions and investigating them. This paper focuses on data collection from the cyber system and web browser. The FTK 4.0 is discussing for memory forensic analysis and remote system forensic which is to be used as evidence for aiding investigation.
 

Soleimani, M.T., Kahvand, M..  2014.  Defending packet dropping attacks based on dynamic trust model in wireless ad hoc networks. Mediterranean Electrotechnical Conference (MELECON), 2014 17th IEEE. :362-366.

Rapid advances in wireless ad hoc networks lead to increase their applications in real life. Since wireless ad hoc networks have no centralized infrastructure and management, they are vulnerable to several security threats. Malicious packet dropping is a serious attack against these networks. In this attack, an adversary node tries to drop all or partial received packets instead of forwarding them to the next hop through the path. A dangerous type of this attack is called black hole. In this attack, after absorbing network traffic by the malicious node, it drops all received packets to form a denial of service (DOS) attack. In this paper, a dynamic trust model to defend network against this attack is proposed. In this approach, a node trusts all immediate neighbors initially. Getting feedback from neighbors' behaviors, a node updates the corresponding trust value. The simulation results by NS-2 show that the attack is detected successfully with low false positive probability.

2015-05-05
Buja, G., Bin Abd Jalil, K., Bt Hj Mohd Ali, F., Rahman, T.F.A..  2014.  Detection model for SQL injection attack: An approach for preventing a web application from the SQL injection attack. Computer Applications and Industrial Electronics (ISCAIE), 2014 IEEE Symposium on. :60-64.

Since the past 20 years the uses of web in daily life is increasing and becoming trend now. As the use of the web is increasing, the use of web application is also increasing. Apparently most of the web application exists up to today have some vulnerability that could be exploited by unauthorized person. Some of well-known web application vulnerabilities are Structured Query Language (SQL) Injection, Cross-Site Scripting (XSS) and Cross-Site Request Forgery (CSRF). By compromising with these web application vulnerabilities, the system cracker can gain information about the user and lead to the reputation of the respective organization. Usually the developers of web applications did not realize that their web applications have vulnerabilities. They only realize them when there is an attack or manipulation of their code by someone. This is normal as in a web application, there are thousands of lines of code, therefore it is not easy to detect if there are some loopholes. Nowadays as the hacking tools and hacking tutorials are easier to get, lots of new hackers are born. Even though SQL injection is very easy to protect against, there are still large numbers of the system on the internet are vulnerable to this type of attack because there will be a few subtle condition that can go undetected. Therefore, in this paper we propose a detection model for detecting and recognizing the web vulnerability which is; SQL Injection based on the defined and identified criteria. In addition, the proposed detection model will be able to generate a report regarding the vulnerability level of the web application. As the consequence, the proposed detection model should be able to decrease the possibility of the SQL Injection attack that can be launch onto the web application.

2015-05-04
Fatemi Moghaddam, F., Varnosfaderani, S.D., Mobedi, S., Ghavam, I., Khaleghparast, R..  2014.  GD2SA: Geo detection and digital signature authorization for secure accessing to cloud computing environments. Computer Applications and Industrial Electronics (ISCAIE), 2014 IEEE Symposium on. :39-42.

Cloud computing is a new paradigm and emerged technology for hosting and delivering resources over a network such as internet by using concepts of virtualization, processing power and storage. However, many challenging issues are still unclear in cloud-based environments and decrease the rate of reliability and efficiency for service providers and users. User Authentication is one of the most challenging issues in cloud-based environments and according to this issue this paper proposes an efficient user authentication model that involves both of defined phases during registration and accessing processes. Geo Detection and Digital Signature Authorization (GD2SA) is a user authentication tool for provisional access permission in cloud computing environments. The main aim of GD2SA is to compare the location of an un-registered device with the location of the user by using his belonging devices (e.g. smart phone). In addition, this authentication algorithm uses the digital signature of account owner to verify the identity of applicant. This model has been evaluated in this paper according to three main parameters: efficiency, scalability, and security. In overall, the theoretical analysis of the proposed model showed that it can increase the rate of efficiency and reliability in cloud computing as an emerging technology.