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Stelios Erotokritou, Srijith K. Nair, Theo Dimitrakos, "An efficient secure shared storage service with fault and investigative disruption tolerance", 2nd International Workshop on Security in Cloud Computing (SCC'2010), Sept. 13-16, 2010, San Diego, California, USA.
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Theo Dimitrakos, David Brossard, Pierre de Leusse and Srijith K. Nair, "Security of Service Networks",
Handbook of Information and Communication Security, Stavroulakis, Peter; Stamp, Mark (Eds.), Springer, pp. 349--380, January 2010.
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Pierre de Leusse, Panos Periorellis, Theo Dimitrakos and Srijith K. Nair, "Self Managed Security Cell: A Security Model for the Internet of
Things and Services",The First International Conference on Advances in Future Internet, AFIN 2009, 18-23 June 2009, Athens/Glyfada, Greece.
pp. 47--52, IEEE Computer Society (Best Paper Award). PDF,
Show Abstract
The Internet of Things and Services is a rapidly
growing concept that illustrates that the ever increasing amount
of physical items of our daily life which become addressable
through a network could be made more easily manageable and
usable through the use of Services. This surge of exposed
resources along with the level of privacy and value of the
information they hold, together with the increase of their usage
make for an augmentation in the number of the security threats
and violation attempts that existing security systems do not
appear robust enough to address. In this paper, the authors
underline this increase in risk and identify the requirements for
resources to be more resilient in this type of environment while
keeping an important level of flexibility. In addition, the authors
propose an architectural model of Self Managed Security Cell,
which leverages on current knowledge in large scale security
systems, information management and autonomous systems.
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Gian Paolo Jesi, Edoardo Mollona, Srijith K. Nair and Maarten van Steen, "Prestige-based Peer Sampling Service:
Interdisciplinary Approach to Secure Gossip", 24th Annual ACM Symposium on Applied Computing, March 8-12, 2009,
Honolulu, Hawaii, USA. PDF,
Show Abstract
The Peer Sampling Service (PSS) has been proposed as a mechanism
to initiate and maintain the set of connections between
nodes in unstructured peer to peer (P2P) networks. The PSS
usually relies on gossip-style communication where participants
exchange their links in a randomized way. However, the PSS network
organization can be easily modified by malicious nodes running
a "hub attack", in which they achieve a leading structural position.
From this prestigious status, the malicious nodes can severely
affect the overlay and achieve several application dependent advantages.
We present a novel method to overcome this attack and provide
results from simulation experiments that validate our claim.
This method is inspired by a simple technique used to detect social
leaders in firm's organizations that is based on the social (structural)
"prestige" of actors.
- Mohammad T. Dashti, Srijith K. Nair and Hugo L. Jonker, "Nuovo DRM Paradiso:Designing a Secure, Verified Fair DRM Scheme",
Fundamentae Informatica (FI), IOS Press, 89, pp. 1--25, 2008. PDF, IOS
Press, Show Abstract
We introduce Nuovo DRM, a digital rights management scheme aimed to be
secure from both a formal and a practical point of view. The scheme is
based on the recent DRM scheme of Nair et al., which we formally specify
in the µcrl process algebraic language. Nair et al. state the
following security requirements: effectiveness, secrecy, resistance of
content masquerading and strong fairness. These security requirements
are formalised and the scheme is formally checked against
these requirements. The finite model-check uncovered several security
weaknesses, which are addressed by Nuovo DRM. In addition to that, Nuovo
DRM introduces several procedural practices to enhance the security of
the scheme. A finite model of Nuovo is subsequently model-checked and
shown to satisfy its design requirements, including secrecy, fairness
and resistance to content masquerading.
- Srijith K. Nair, Gabriela Gheorghe, Bruno Crispo and Andrew S. Tanenbaum, "Enforcing DRM Policies Across Applications",
8th ACM DRM Workshop (DRM 2008), Co-located with ACM CCS 2008, pp. 87-94,
October 27, 2008, Alexandria, Virginia, USA. PDF, Show Abstract
In this paper we present Trishul-UCON (T-UCON), a DRM system based on the UCON_ABC model. T-UCON is designed to be capable of
enforcing not only application-specific policies, as any existing software-based DRM solution does, but also DRM policies across
applications. This is achieved by binding the DRM policy only to the content it protects with no relations to the application(s)
which will use this content. Furthermore, to guarantee that the policy is continuously enforced, we designed T-UCON as a JVM-based
middleware that mediates the usage requests of any Java application to the protected content. Each request is granted or denied
according to the content policy. We illustrate the unique features of T-UCON by using typical examples of DRM policies such as
the pay-per-use and the use only N times scenarios. Preliminary results on the overhead of our solution are also provided.
- Srijith K. Nair, Erik Zentveld, Bruno Crispo, Andrew S. Tanenbaum, "Floodgate: A Micropayment Incentivised P2P Content
Delivery Network" - 17th IEEE International Conference on Computer Communications and Networks (ICCCN 2008),
August 3 - 7, 2008, St. Thomas U.S. Virgin Islands, USA. - PDF, Show Abstract
As the sale of digital content is moving more and more online, the content providers are beginning to realise that bandwidth infrastructures are
not easily scalable. The emergence of peer-to-peer content delivery networks presents these providers with a way to overcome this limitation.
However, such networks have so far been ad-hoc in nature. One of the main reason for this
has been the lack of incentives for end users to contribute their bandwidth to the network. In this paper we present the design and implementation of
a peer-to-peer protocol named Floodgate that provides a micropayment based incentive for peers to contribute their bandwidth.
Floodgate implements an optimistic fair exchange protocol and is designed to be resilient against targeted attacks.
Performance measurements, including those conducted over the PlanetLab infrastructure, show that Floodgate's security and cryptographic overheads are low
when compared to the popular BitTorrent protocol. (pre-proceedings version)
- Srijith K. Nair, Patrick N.D. Simpson, Bruno Crispo and Andrew S. Tanenbaum, "A Virtual Machine Based Information Flow Control System for Policy
Enforcement" - Electronic Notes in Theoretical Computer Science, Vol. 197, Issue 1, 21 February 2008, pp. 3-16, Proc. of the First International Workshop on
Run Time Enforcement for Mobile and Distributed Systems (REM 2007), Sep 27, 2007, Dresden,
Germany. (doi:10.1016/j.entcs.2007.10.010), - PDF (pre-proceeding version),
Show Abstract
The ability to enforce usage policies attached to data in a fine grained manner requires that the system be
able to trace and control the flow of information within it. This paper presents the design and implementation
of such an information flow control system, named Trishul, as a Java Virtual Machine. In particular
we address the hard problem of tracing implicit information flow, which had not been resolved by previous
run-time systems and the intricacies added on by the Java architecture. We argue that the security benefits
offered by Trishul are substantial enough to counter-weigh the performance overhead of the system as shown
by our experiments.
- Srijith K. Nair, Ron Gerrits, Bruno Crispo, Andrew S. Tanenbaum "Turning Teenagers into Stores", IEEE Computer, vol. 41, no. 2, pp. 58-62, Feb., 2008
(PDF),
Show Abstract
Paradiso is a prototype of a system that lets consumers contact content providers to buy
songs and videos, and to buy optional content-resale rights. In essence, the scheme would
turn customers into content distributors, provide wider reach, and free up content providers'
bandwidth. However, such an architecture requires strict security precautions and interoperable
digital rights management standards among player manufacturers and content providers.
- Srijith K. Nair, Ivan Djordjevic, Bruno Crispo, Theo Dimitrakos, "Secure Web Service Federation Management
using TPM Virtualisation" - 4th ACM Workshop on Secure Web Services (SWS
2007), pp. 73-82, Nov 2, 2007, Alexandria, VA, USA. PDF
Show Abstract
Web Services and SOA provide interoperability and architectural
baseline for flexible and dynamic cross-enterprise collaborations,
where execution and use of the participating services contributes
to the common objective. Relationships within these
collaborations are complex, with services joining and leaving
throughout the life cycle, or the same services being offered in
several collaborations simultaneously. This provides strong
requirements for federated security, where integrity and
confidentiality of the collaboration must be maintained through
membership control, security policy enforcement and separation
of web service instance interactions in different collaborations.
In this paper we propose a new Web Services (WS) framework for
managing and controlling WS interactions in a federated
environment, leveraging on platform virtualisation architecture
and the functionalities provided by trusted secure hardware. The
framework allows configuring policies that define collaboration
membership, and enforce access to the collaboration per-WS
instance. In addition, since the access to the configurations is
restricted, it provides master-slave model where only authorised
administrative entity can modify any of the above - either at the
deployment or at the execution time. Some of the benefits of the
proposed approach are: fine-grained external exposure of WSs, a
flexible model for group membership control and revocation and
hardware-enabled secure virtualised system providing functional
process isolation and strong data security.
- Ivan Djordjevic, Srijith K. Nair, Theo Dimitrakos, "Virtualised Trusted Computing Platform for Adaptive Security
Enforcement of Web Services Interactions" - IEEE 2007 International Conference on Web Services
(ICWS07), pp. 615-622, July 9-13, 2007, Salt Lake City, Utah, USA -
PDF,
Show Abstract
Security enforcement framework is an important
aspect of any distributed system. With new
requirements imposed by SOA-based business models,
adaptive security enforcement on the application level
becomes even more important.
Our work on the enforcement framework to date has
resulted in a comprehensive middleware-based
solution leveraging on web services technologies.
However, potential merits of hardware-based solutions
to further secure application exposure have not been
considered so far.
This paper describes a method for combining software
resource level security features offered by Web
Services technologies, with the hardware-based
security mechanisms offered by Trusted Computing
Platform and system virtualisation approaches. In
particular, we propose trust-based architecture for
protecting the enforcement middleware deployed at the
policy enforcement endpoints of web and grid services.
The main motivation is to additionally secure execution
environment of the applications, by providing virtual
machine level separation that maps from logical
domains imposed by web services level enforcement
policies.
- Nair, S.,Dashti, M.,Crispo, B., and Tanenbaum, A., "A Hybrid PKI-IBC Based Ephemerizer System", 2007, in IFIP
International Federation for Information Processing, Volume 232,
New Approaches for Security, Privacy and Trust in Complex Environments, eds. Venter, H., Efloff, M.,Labuschagne, L., Eloff, J., von
Solms, R., (Boston: Springer), pp. 241-252. - PDF, SpringerLink,
Show Abstract
The concept of an Ephemerizer system has been introduced
in earlier works as a mechanism to ensure that a file deleted from the
persistent storage remains unrecoverable. The principle involved storing
the data in an encrypted form in the user's machine and the key to de-
crypt the data in a physically separate machine. However the schemes
proposed so far do not provide support for fine-grained user settings on
the lifetime of the data nor support any mechanism to check the in-
tegrity of the system that is using the secret data. In addition we report
the presence of a vulnerability in one version of the proposed scheme
that can be exploited by an attacker to nullify the ephemeral nature of
the keys. We propose and discuss in detail an alternate Identity Based
cryptosystem powered scheme that overcomes the identified limitations
of the original system.
- Mohammad T. Dashti, Srijith K. Nair, Hugo L. Jonker, "Nuovo DRM Paradiso: Towards a Verified Fair DRM Scheme" -
Proceedings of IPM International Symposium on Fundamentals of Software Engineering (FSEN07), pp. 33-48, April 17-19 2007, Tehran, Iran. - PDF, SpringerLink
, Show Abstract
We formally specify the recent DRM scheme of Nair et al.
in the µcrl process algebraic language. The security requirements of
the scheme are formalized and using them as the basis, the scheme is
verifed. The verifcation shows the presence of security weaknesses in the
original protocols, which are then addressed in our proposed extension
to the scheme. A fnite model of the extended scheme is subsequently
model checked and shown to satisfy its design requirements, including
secrecy, fairness and resisting content masquerading. Our analysis was
distributed over a cluster of machines, allowing us to check the whole
extended scheme despite its complexity and high non-determinacy.
- Hugo Jonker, Srijith Krishnan Nair, Mohammad Torabi Dashti, "Nuovo DRM Paradiso: towards a verified fair DRM protocol", 1st Benelux Workshop on Information
and System Security (WISSEC2006), November 8-9, 2006, Antwerpen, Belgium. -
PDF File,
Show Abstract
The NPGCT DRM scheme, that proposes a unique concept of DRM-preserving
content redistribution, has some security issues. These issues are addressed in this paper
by an extension of NPGCT. A security mechanism that provides fairness in unsupervised
exchanges is introduced, and the mechanism of detecting and revoking circumvented devices
is reexamined devices. The resulting DRM scheme, Nuovo DRM, and its requirements are
formally specifed. A fnite model of the scheme is subsequently model-checked and shown
to satisfy its design requirements.
- Srijith K. Nair "Policy binding and enforcement in Java", Workshop on Run-time Software Integrity and Authenticity, September 18-19,
2006, Trento, Italy.
- Srijith K. Nair, Bruno Crispo, Andrew S. Tanenbaum, "Towards a Secure Application-semantic Aware Policy Enforcement Architecture",
in Proceedings of the 14th International Workshop on Security Protocols 2006, Cambridge,
UK, pages 26-31. Springer-Verlag LNCS 5087, 2009. (B. Christianson, B. Crispo, J.A. Malcolm, and M. Roe, editors)
- PDF,
Show Abstract
Even though policy enforcement has been studied from different angles including notation, negotiation and enforcement, the
development of an application-semantic aware enforcement architecture remains an open problem. In this paper we present
and discuss the design of such an architecture.
- Srijith K. Nair, Bogdan C. Popescu, Chandana Gamage, Bruno Cripso, Andrew S. Tanenbaum, "Enabling DRM-preserving Digital Content Redistribution" -
Proceedings of 7th International IEEE Conference on E-Commerce Technology 2005 (CEC2005), pp. 151-158
July 19-22, 2005, Munich, Germany. - PDF
File, IEEE Xplorer, DBLP,
Show Abstract
Traditionally, the process of online digital content distribution has involved a limited number of centralised distributors
selling protected contents and licenses authorising the use of these contents, to consumers. In this paper, we extend
this model by introducing a security scheme that enables DRM preserving digital content redistribution. Essentially
consumers can not only buy the rights to use digital content but also the rights to redistribute it to other consumers in
a DRM controlled fashion. We examine the threats associated with such a redistribution model and explain how our
scheme addresses them.
- Srijith K. Nair, Lillykutty Jacob, Akkihebbal L. Ananda, "TCP Vegas-A: Improving the performance of TCP Vegas", Computer Communications, vol. 28,
no. 4, pp. 429-440, March 2005 - PDF File, DBLP,
Show Abstract
While it has been shown that TCP Vegas provides better performance compared to TCP Reno, studies have identified various issues
associated with the protocol. We propose modifications to the congestion avoidance mechanism of the TCP Vegas to overcome these
limitations. Unlike the solutions proposed in the past, our solution, named TCP Vegas-A, is neither dependent on optimising any critical
parameter values nor on the buffer management scheme implemented at the routers and hence can be implemented solely at the end host. Our
simulation experiments over wired as well as over geosynchronous and lower earth orbit satellite links show that TCP Vegas-A is able to
overcome several of the identified problems-it can obtain a fairer share of the network bandwidth in wired and satellite scenarios, tackle
rerouting issues, rectify Vegas's bias against higher bandwidth flows and prevail over fluctuating RTT conditions of a
lower earth orbit
satellite link. At the same time, Vegas-A is able to preserve the unique properties of Vegas that had made it a noteworthy protocol.
- K.N. Srijith, Lillykutty Jacob and A.L. Ananda, "TCP Vegas-A: Solving the Fairness and Rerouting Issues of TCP Vegas", - Proceedings of 22nd IEEE
International Performance, Computing, and Communications Conference (IPCCC) 2003, pp. 309-316, Phoenix, Arizona, April 9 - 11, 2003.
- PDF File, IEEE Xplorer,
Show Abstract
In spite of the larger performance gain such as higher throughput and almost zero packet retransmissions compared to TCP Reno, TCP Vegas still has a few obstacles
for it to be deployed in the Internet. Studies have shown unfair treatment to Vegas connections when they compete with Reno connections. Other issues identified
with TCP Vegas are problems of rerouting, persistent congestion, and discrepancy in flow rate tied with starting times and link bandwidth. We reinvestigate these
issues rind propose modifications to the congestion avoidance mechanism of the TCP Vegas, with the slow-start and congestion recovery algorithms of Vegas remaining
untouched. Unlike the solutions proposed in the recent past to deal with some of these issues, our solution it neither dependent on any critical parameter values
nor on the buffer management scheme at the routers (e.g., RED). Our experiments show that the modified TCP Vegas (Vegas-A) it able to obtain a fairer share of the
network bandwidth when competing with other TCP flows. We also show that Vegas-A can tackle rerouting issues and rectify Vegas's bias against higher bandwidth
flows. At the same time, our experiments prove that Vegas-A preserves the properties of Vegas that have made it a noteworthy protocol.
- K.N. Srijith, Lillykutty Jacob and A.L. Ananda, "Worst-case Performance Limitation of TCP SACK and a Feasible Solution", - Proceedings of 8th IEEE
International Conference on Communications Systems (ICCS), pp. 1157-1161, November 25-28, 2002, Singapore. - PDF File, Citeseer
Index,
Show Abstract
In the present implementation of the transmission control protocol (TCP) selective acknowledgment (SACK), every SACK block needs 8 bytes to carry information about
the received packets, back to the sender. Since TCP options field has a fixed length, there is a limit on the number of SACK block that can be carried by the
acknowledgment packets. Under some error conditions, this limitation can force the TCP sender to retransmit packets that have already been received successfully by
the receiver. This paper puts forward a proposal to modify the present SACK implementation, in order to prevent these unwanted retransmissions. We show that the
proposed implementation of SACK mechanism increases the throughput of SACK enabled TCP connections.
- Lillykutty Jacob, K.N. Srijith, Huang Duo and A.L.Ananda, "Effectiveness of TCP SACK, TCP HACK and TCP Trunk over Satellite Links" - IEEE International
Conference
on Communications (ICC 2002), Vol.5, pp. 3038 - 3043, April 28 - May 2, 2002. - PDF
File, Citeseer Index,
Show Abstract
This paper reports a study on the performance enhancements of two extensions to the standard TCP implementation - Selective Acknowledgement (SACK) and Header
Checksum (HACK) - over satellite links that are characterized by high latency and high bit error rate. We also examine the effectiveness of TCP Trunk, an
edge-to-edge aggregation and congestion control mechanism, over the satellite link. Our study on the effect of varying the TCP window size over a long latency link
for New Reno, SACK, HACK and TCP Trunk implementations show that increasing window size does improve the performance, but only up to a certain value of the window
size, and a further increase actually reduces the performance. Other interesting observations from our experimental study are: SACK enabled TCP Trunk across the
satellite link edge routers can improve the throughput regardless of the end host TCP implementation; disabling the link layer CRC and instead implementing the
HACK extension to the TCP (and of course HACK+ SACK) can improve the throughput further.
- Yongxiang Liu, K.N. Srijith, L. Jacob and A.L.Ananda,"TCP-CM: A Transport Protocol for TCP-friendly Transmission of Continuous Media" - Proceedings of
21st IEEE
International Performance, Computing and Communications Conference (IPCCC 2002), pp. 83-91, April 3-5, 2002, Phoenix, Arizona. -
PDF File, Citeseer
Index,
Show Abstract
We propose a new TCP friendly transport protocol, called TCP-CM, for continuous media applications over the Internet. TCP-CM is a direct modification of TCP to
support continuous media applications without compromising the congestion control feature of TCP, which is critical to the stable functioning of the Internet. We
design TCP-CM API to be compatible with the BSD socket interface, which requires minimum changes for applications to adopt TCP-CM. Continuous media applications
that adopt TCP-CM as the transport protocol can be relieved from burdens such as rate control and scheduling for timely delivery, and hence can focus solely on
advanced coding or compression techniques for adapting the content according to the available network bandwidth. We implement the TCP-CM in Linux 2.2.15 TCP/IP
protocol stack, and run extensive experiments on TCP-CM using emulated video flows. Our experiments show that TCP-CM can be used for the timely delivery of
continuous media data within the constraints of the available network bandwidth and can compete with TCP connections fairly.
- K.N. Srijith, V. Ranjit, B.S. Ooi, Y.C. Chan, Y.L. Lam, C.H. Kam, "Fabrication And Characterisation of Bandgap Tuned Lasers in GaAs/AlGaAs Quantum Well Structures Using Pulsed Laser Irradiation", Proceeding of 4th National Symposium On Progress in Materials Research, (Best Postar Award), pp. 137--139, March 27, 1998, Singapore, PDF.
-
V. Ranjit, K.N. Srijith, B.S. Ooi, Y.C. Chan, Y.L. Lam, C.H. Kam, "Characterisation of GaAs/AlGaAs Extended Cavity lasers fabricated using dielectric
cap induced quantum well intermixing", Proceeding of 4th National Symposium On Progress in Materials Research, pp. 133-136, Singapore, 27th March 1998.
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