Securing the Internet with digital signatures

Lecturer : 
Dmitrij Lagutin
Event type: 
Doctoral dissertation
Event time: 
2010-12-10 12:00 to 15:00
Place: 
Computer science building, hall T2, Konemiehentie 2, Otaniemi, Espoo
Description: 

Opponent: Associate Professor Panagiotis Papadimitratos, KTH School of Electrical Engineering, Sweden
Supervisor: Professor Antti Ylä-Jääski

The dissertation will be available at:
http://lib.tkk.fi/Diss/2010/isbn9789526034652/

Abstract:
The security and reliability of the Internet are essential for many functions of a modern society. Currently, the Internet lacks efficient network level security solutions and is vulnerable to various attacks, especially to distributed denial-of-service attacks. Traditional end-to-end security solutions such as IPSec only protect the communication end-points and are not effective if the underlying network infrastructure is attacked and paralyzed.

This thesis describes and evaluates Packet Level Authentication (PLA), which is a novel method to secure the network infrastructure and provide availability with public key digital signatures. PLA allows any node in the network to verify independently the authenticity and integrity of every received packet, without previously established relationships with
the sender or intermediate nodes that have handled the packet. As a result, various attacks against the network and its users can be more easily detected and mitigated, before they can cause significant damage or disturbance. PLA is compatible with the existing Internet infrastructure, and can be used with complementary end-to-end security solutions, such as IPSec and HIP. While PLA was originally designed for securing current IP networks, it is also suitable for securing future data-oriented networking approaches.

PLA has been designed to scale from lightweight wireless devices to Internet core network, which is a challenge since public key cryptography operations are very resource intensive. Nevertheless, this work shows that digital signature algorithms and their hardware implementations developed for PLA are scalable to fast core network routers. Furthermore, the additional energy consumption of cryptographic operations is significantly lower than the energy cost of wireless transmission, making PLA feasible for lightweight wireless devices. Digital signature algorithms used by PLA also offer small key and signature sizes and therefore PLA's bandwidth overhead is relatively low.

Strong security mechanisms offered by PLA can also be utilized for various other tasks. This work investigates how PLA can be utilized for controlling incoming connections, secure user authentication and billing, and for providing a strong accountability without an extensive data retention by network service providers.

Cross-layer Assisted TCP Algorithms for Vertical Handoff

Event type: 
Doctoral dissertation
Doctoral dissertation
Respondent: 
Laila Daniel
Opponent: 
Professor Xiaoming Fu
Custos: 
Professor Jussi Kangasharju
Event time: 
2010-11-20 10:00 to 12:00
Place: 
Auditorium XII in the Main Building
Description: 

Laila Daniel will defend her thesis "Cross-layer Assisted TCP Algorithms for Vertical Handoff" on Saturday,

20 November 2010 at 10.00. in Auditorium XII in the Main Building. Her opponent is Professor Xiaoming Fu,

Georg-August-University of Göttingen, Germany, and her custos Professor Jussi Kangasharju.

 

 Popular abstract:

Increasingly we use our mobile devices (e.g., mobile phones, laptops) for diverse applications such as
reading e-mail, browsing the web, downloading and listening to music, playing games and for making payments
for products and services irrespective of our location and mobility by connecting the mobile device to
the Internet anytime anywhere.

Access networks that enable a mobile device to connect to the Internet use diverse technologies and differ
widely in their characteristics. Mobile devices inherently use wireless access networks by means of radios
for Internet connectivity. For example, Wireless Local Area Network (WLAN) is a fast network that can be used
inside a building whereas General Packet Radio Service (GPRS) is comparatively slower and can span a city or
a country and even beyond. A mobile device with multiple radio interfaces can changeover to any of the several
access networks depending on its location or the application needs. Handoff refers to this changeover and it
is known as vertical handoff when the underlying technologies of the two access networks are different.

TCP, a data communication software, which resides both at the sender and the receiver of data, delivers the
application data reliably and also adjusts its sending rate depending on the availability of the resources
in the Internet. TCP behaviour depends on the characteristics of the end-to-end path and in particular the
bottleneck link, the link with minimum capacity in the path. A wireless link that connects the mobile device
to the Internet is often the bottleneck link and the abrupt change in its characteristics due to a vertical
handoff significantly affects TCP performance and consequently the application quality.

The focus of this thesis is to study TCP behaviour in a vertical handoff and to devise algorithms to improve
its handoff performance using cross-layer notification to convey information about the characteristics of the
access links involved in the handoff. Our first study is in the WLAN-GPRS environment with minimum information to
TCP about the handoff and the results show that TCP performance can be significantly improved. Subsequently we
enlarge the scope of the study to cover a more general case using rough estimates of the access link parameters.
The evaluation of the algorithms is based on simulation experiments with a wide range of access networks showing
that TCP performance in handoff can be significantly improved using this approach. Our algorithms can be useful
to devise solutions for the real world scenarios.

Statistical dependencies in analysis of naturalistic brain stimulation

Lecturer : 
Arto Klami
Event type: 
HIIT seminar
Event time: 
2010-11-19 10:15 to 11:00
Place: 
Exactum C222
Description: 

Talk announcement:
HIIT Seminar Kumpula, Friday Nov 19, 10:15 a.m., Exactum C222

On Nov 19 HIIT Seminar Kumpula features a talk by Arto Klami from the HIIT Statistical Machine Learning and Bioinformatics group. The presentation will include a short and accessible overview of the group.

Welcome!
--Matti Järvisalo

---------------------------------------------------------------------


SPEAKER:
Arto Klami
Helsinki Institute for Information Technology HIIT / Aalto University

TITLE:
Statistical dependencies in analysis of naturalistic brain stimulation

ABSTRACT:
Use of more naturalistic experimental conditions is currently one of the major trends in neuroscience. Instead of controlled experiments the brains are being scanned for example when the subject is watching a movie. Naturalistic stimulation opens up new possibilities for understanding the brain, but the classical analysis tools are not sufficient for these new setups. I will introduce a new approach based on extracting statistical dependencies between brain activity and rich feature representations of the stimulus and discuss the necessary modeling tools.

BIO:
Arto Klami is a postdoc researcher at the Department of Information and Computer Science at Aalto University. He received his PhD in computer science at Helsinki University of Technology in 2008, and is currently working on an Academy of Finland postdoctoral researcher's project. His research interests include Bayesian modeling, proactive interfaces, and analysis of neuroimaging data.

Computational Methods for Detecting Large-Scale Chromosome Rearrangements in SNP Data

Event type: 
Doctoral dissertation
Doctoral dissertation
Respondent: 
Jussi Kollin
Opponent: 
Docent Sampsa Hautaniemi
Custos: 
Professor Esko Ukkonen
Event time: 
2010-10-25 12:00 to 14:00
Place: 
Main Building, auditorium XII
Description: 

Jussi Kollin will defend his thesis 'Computational Methods for Detecting Large-Scale Chromosome Rearrangements in SNP Data' on Monday 25 October at 12 noon in the university's Main Building, auditorium XII. His custos is Professor Esko Ukkonen and opponent Docent Sampsa Hautaniemi.

Abstract:

Large-scale chromosome rearrangements such as copy number variants (CNVs)  and inversions encompass a considerable proportion of the genetic  variation between human individuals. In a number of cases, they have been  closely linked with various inheritable diseases. 

Single-nucleotide polymorphisms (SNPs) are another large part of the  genetic variance between individuals. They are also typically abundant and  their measuring is straightforward and cheap. 

This thesis presents computational means of using SNPs to detect the  presence of inversions and deletions, a particular variety of CNVs.  Technically, the inversion-detection algorithm detects the suppressed  recombination rate between inverted and non-inverted haplotype populations  whereas the deletion-detection algorithm uses the EM-algorithm to estimate  the haplotype frequencies of a window with and without a deletion  haplotype. As a contribution to population biology, a coalescent simulator  for simulating inversion polymorphisms has been developed. Coalescent  simulation is a backward-in-time method of modelling population ancestry.  Technically, the simulator also models multiple crossovers by using the  Counting model as the chiasma interference model. 

Finally, this thesis includes an experimental section. The aforementioned  methods were tested on synthetic data to evaluate their power and  specificity. They were also applied to the HapMap Phase II and Phase III  data sets, yielding a number of candidates for previously unknown  inversions, deletions and also correctly detecting known such  rearrangements.

User Interfaces and the Environment: Exploiting Human Abilities to Improve Mobile Interaction

Lecturer : 
Antti Oulasvirta
Event type: 
HIIT seminar
Event time: 
2010-11-01 13:15 to 14:00
Place: 
Computer Science building, hall T2
Description: 

Our next speaker for HIIT Otaniemi seminar series is Antti Oulasvirta from the
"Ubiquitous Interaction" group of the Helsinki Institute for Information
Technology HIIT. Before his talk, he will also give a short overview on the
research areas of the group.

All ICS@Aalto researchers are also warmly welcome to attend the seminar!

HIIT seminar Otaniemi, Monday November 1, 13:15
Location: Computer Science building, hall T2


Antti Oulasvirta
Ubiquitous Interaction Group
Helsinki Institute for Information Technology HIIT

Title:
User Interfaces and the Environment: Exploiting Human Abilities to Improve Mobile Interaction

Abstract:
In the field of human-computer interaction (HCI), user interfaces have been analyzed in terms of information exchange  between the human user and the computer. In my work, I have started to investigate mobile interfaces as a special case in  HCI where the environment plays a critical role. This talk first seeks to prove that, if approached within the traditional  frameworks of HCI, mobile interfaces will remain inherently inferior in comparison to their desktop counterparts. I will then  make a case for "embodied interaction"--i.e., leveraging users' knowledge of their environment, their ability to exploit its  structure, and their ability to transform tasks by means of action. Mobile mixed reality interfaces is emerging as a promising  area that puts the ideas of embodied interaction into practice, demonstrating ways in which mobile users can literally sense  and act through digital information. To conclude, I will argue that embodied interaction 1) will eventually go beyond the rates of  information throughput possible for traditional mobile interfaces and 2) may emerge as a key enabler for the next  generation of mobile computers.

Short Bio:
Antti Oulasvirta is a Senior Researcher at the Helsinki Institute for Information Technology HIIT where he directs the  Ubiquitous Interaction group (http://www.hiit.fi/uix). His research focus lies at the intersection of human-computer interaction, mobile and ubiquitous computing, and cognitive psychology. Dr. Oulasvirta received his doctorate in Cognitive Science from the University of Helsinki in 2006, after which he was a Fulbright Scholar at the School of Information in UC Berkeley. During his postgraduate studies, he was an exchange student at UC Berkeley’s Neuropsychology Lab and did an internship at
T-Labs in Berlin. Dr. Oulasvirta is a docent (adjunct faculty) of computer science at the University of Helsinki and a docent of cognitive science at the University of Jyväskylä.

For more information (full CV and publications), please see:
http://www.hiit.fi/u/oulasvir

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