Category Archives: Acadia seminar series

18/01/2018 – Talk by Martina Olliaro

Title:Marie Sklodowska-Curie Actions: Individual Fellowships
Time: 13:00
Location: Meeting room, Building Zeta
Type: Funding opportunities
Speaker: Martina Olliaro
Abstract: Are you an experience researcher and you don’t know what your next career move might be? Let yourself be inspired and enticed by the funding opportunities offered by the Marie Sklodowska-Curie Actions. In particular, I wish to make a point of highlighting on the Individual Fellowships action that, through an abroad working experience, mashing training and research, allows you to grow both as a person and as a professional, to enrich your curriculum and to enhance your career development.

12/12/2017 – Talk by Euripides Markou

Title:Exploration and graph searching problems in networks
Time: 13:00
Location: Meeting room, Building Zeta
Type: Research Result
Speaker: Talk by Euripides Markou
Abstract: In this seminar we will discuss different problems in networks: The Black Hole Search problem in synchronous trees and graphs; the Black Hole Search problem and the rendezvous problem for weak agents (e.g., memoryless). We will show algorithms and discuss impossibility results, new directions and open problems.
Short bio: Euripides Markou is an Assistant Professor at the University of Thessaly. He got his Ph.D. in Computer Science in 2003 from the National University of Athens. His area of interest are in the field of distributed and geometric computing.

12/12/2017 – Talk by Novarun Deb

Title:Enterprise Modelling and Requirements Analysis using the i* Framework
Time: 14:00
Location: Meeting room, Ed. Zeta
Type: Research Result
Speaker: Talk by Novarun Deb
Abstract:We identify that the inherent sequence agnostic property of goal models prevents requirement analysts from performing compliance checks in the requirements phase itself as compliance rules are generally embedded with temporal information. This is where we propose the Semantic Implosion Algorithm that extracts a finite state model corresponding to a given goal model with the help of model transformation. This algorithm outperforms the existing solution by a factor of 1017, making our solution more efficient and scalable for deployment in the real world. We also develop the iToNuSMV tool that implements the Semantic Implosion Algorithm and performs model checking on i models. Subsequently, we go beyond structural analysis and try to explore the semantics associated with goal models and how they can be used in the goal model maintenance problem. Our final research contribution is the Annotation of Functional Semantics and their Reconciliation AFSR framework that provides a new goal model nomenclature that goes beyond the legacy nomenclature and associates semantics with individual goals. The framework also provides a reconciliation machinery that helps to perform semantic analysis and detect entailment or consistency conflicts within goal models. The framework also provides analysts with corrective measures that can be adopted to resolve such conflicts. We also demonstrate how the goal maintenance problem can be mapped to the state space search problem and an admissible and consistent heuristic path cost function allows us to deploy A search to find the optimal goal model configuration that is free from all conflicts.

30/11/2017 – Talk by Ludovica Luisa Vissat

Title: Modelling of spatial stochastic systems and analysis of their spatio-temporal properties
Time: 13:00
Location: Meeting room, Ed. Zeta
Type: Research Result
Speaker: Ludovica Luisa Vissat
Abstract: In my talk I will give an overview of my PhD research work. We have initially developed a novel process algebra, specifically tailored for modelling ecological systems, and more generally for spatial stochastic systems. These systems can be seen as a collection of agents that can interact and are spatially located. To analyse properties of the dynamics of these stochastic systems, we worked with spatio-temporal logics and statistical model checking.

We introduced the novel Three-Valued Spatio-Temporal Logic, which extends the available analysis, looking at the spatio-temporal evolution of the satisfaction probabilities of given logical formulas, estimated through statistical model checking. I will present different case studies during the talk, to show various applications of our modelling language and spatio-temporal analysis.

24/10/2017 – Talk by Amit Mandal

Title: A Novel Meta-Information Management System for SaaS
Time: 12:15
Location: Meeting room, Ed. Zeta
Type: Research Result
Speaker: Amit Mandal
Abstract: Efficient hosting and provisioning of cloud based software services are complex engineering task with the increasing and heterogeneous SaaS resources. In this context, SaaS resource includes services, business processes, data sources, etc. This demands an efficient categorization and cataloguing mechanism. It can be achieved by exploring and managing the meta-information of various SaaS resources. However, meta-information management system of SaaS should ensure: (i) collection of relevant meta-information about the interrelated services, business processes, and data sources; (ii) easy accessibility and (iii) incremental update. Further, it should capable of tracing the correspondence among different SaaS resources across the cloud. To address these issues we proposed a flexible and scalable meta-information management system for SaaS. It comprises of meta-information crawler, indexer, uploader, and storage system. The crawler collects meta-information from various repositories. On next, the crawled meta-information is uploaded to the Hadoop system using a multidimensional indexing system. Further, to ensure efficient management, easy update, faster storing and retrieval of meta-information a series of experiments have been carried out. The experimental results show that the proposed mechanism can efficiently scale and it can effectively categorise and catalogue different SaaS resources.

17/10/2017 – Talk by Giuseppe Maggiore

Title: GrandeOmega, a smart e-learning platform
Time: 14:00
Location: Meeting room, Ed. Zeta
Type: Research Result
Speaker: Giuseppe Maggiore
Abstract: Teaching programming and mathematics presents a challenge: learning such disciplines requires, at the same time, a heavy does of both theory and practice. Theory provides the overview, the rules, and the fundamental way the discipline is set up. Practice offers context and motivation for the theory, and its repetition breeds familiarity and deeper understanding.

Moreover, while teachers strive towards sharing the beauty and elegance of abstract concepts, students often wish to learn “useful” concepts that have a real-world application, and to experiment with it. Unfortunately, this becomes a chicken-and-egg problem: too much practice overshadows proper learning of the underlying theory, and too much theory demotivates students.

In this talk, we present GrandeOmega, a tool that facilitates the teaching of the formal application of programming languages and similar formalisms in an active, engaging, practical way.

11/10/2017 – Talk by Stefano Calzavara

Title: CCSP: Controlled relaxation of content security policies by runtime policy composition
Time: 12:00 (noon)
Location: ACADIA Lab., Ed. Zeta
Type: Research Result
Speaker: Stefano Calzavara
Abstract: Content Security Policy (CSP) is a W3C standard designed to prevent and mitigate the impact of content injection vulnerabilities on websites by means of browser-enforced security policies. Though CSP is gaining a lot of popularity in the wild, previous research questioned one of its key design choices, namely the use of static white-lists to define legitimate content inclusions. In this talk we present Compositional CSP (CCSP), an extension of CSP based on runtime policy composition. CCSP is designed to overcome the limitations arising from the use of static white-lists, while avoiding a major overhaul of CSP and the logic underlying policy writing. We perform an extensive evaluation of the design of CCSP by focusing on the general security guarantees it provides, its backward compatibility and its deployment cost. We then assess the potential impact of CCSP on the web and we implement a prototype of our proposal, which we test on major websites. In the end, we conclude that the deployment of CCSP can be done with limited efforts and would lead to significant benefits for the large majority of the websites.

19/07/2017 – Talks by Mauro Tempesta, Francesco Palmarini, Heider Wahsheh, Marco Squarcina

The program of the day will be:

11.00 Mauro Tempesta
11.20 Francesco Palmarini
11.40 Heider Wahsheh
14.00 Marco Squarcina

Titles and abstracts follow:

Title: Run-time Attack Detection in Cryptographic APIs
Speaker: Marco Squarcina
Cryptographic APIs are often vulnerable to attacks that compromise
sensitive cryptographic keys. In the literature we find many proposals
for preventing or mitigating such attacks but they typically require to
modify the API or to configure it in a way that might break existing
applications. This makes it hard to adopt such proposals, especially
because security APIs are often used in highly sensitive settings, such
as financial and critical infrastructures, where systems are rarely
modified and legacy applications are very common. In this talk we
propose a different approach. We introduce an effective method to
monitor existing cryptographic systems in order to detect, and possibly
prevent, the leakage of sensitive cryptographic keys. The method
collects logs for various devices and cryptographic services and is able
to detect, offline, any leakage of sensitive keys, under the assumption
that a key fingerprint is provided for each sensitive key. We define key
security formally and we prove that the method is sound, complete and
efficient. We also show that without key fingerprinting completeness is
lost, i.e., some attacks cannot be detected. We discuss possible
practical implementations and we develop a proof-of-concept log analysis
tool for PKCS#11 that is able to detect, on a significant fragment of
the API, all key-management attacks from the literature.

14/07/2017 – Talk by Matus Namec

Title: Measuring Popularity of Cryptographic Libraries in Internet-Wide Scans Fingerprinting
Time: 11:00
Location: Skype call
Type: Research Result
Speaker: Matus Nemec
We measure the popularity of cryptographic libraries in large datasets of RSA public keys. We do so by improving a recently proposed method based on biases introduced by alternative implementations of prime selection in different cryptographic libraries. We extend the previous work by applying statistical inference to approximate a share of libraries matching an observed distribution of RSA keys in an inspected dataset (e.g., Internet-wide scan of TLS handshakes). The sensitivity of our method is sufficient to detect transient events such as a periodic insertion of keys from a specific library into Certificate Transparency logs and inconsistencies in archived datasets.

We apply the method on keys from multiple Internet-wide scans collected in years 2010 through 2017, on Certificate Transparency logs and on separate datasets for PGP keys and SSH keys. The results quantify a strong dominance of OpenSSL with more than 84% TLS keys for Alexa 1M domains, steadily increasing since the first measurement. OpenSSL is even more popular for GitHub client-side SSH keys, with a share larger than 96%. Surprisingly, new certificates inserted in Certificate Transparency logs on certain days contain more than 20% keys most likely originating from Java libraries, while TLS scans contain less than 5% of such keys.

Since the ground truth is not known, we compared our measurements with other estimates and simulated different scenarios to evaluate the accuracy of our method. To our best knowledge, this is the first accurate measurement of the popularity of cryptographic libraries not based on proxy information like web server fingerprinting, but directly on the number of observed unique keys.

14/02/2017 – Talk by Ivan Stojic

Title: Algorithms for stationary analysis of stochastic Petri nets
Time: 12:30
Location: Meeting room, Building Zeta
Type: Research Result
Speaker: Ivan Stojic
Stochastic Petri nets (SPN) are a Markovian formalism for qualitative and quantitative analysis of discrete event dynamic systems. Among other uses, they have been used extensively in performance evaluation of telecommunication systems, computer systems and networks. Analysis of steady-state behaviour of an SPN model usually requires stationary analysis of a continuous-time Markov chain (CTMC) underlying the SPN, whose state space for many practical models is too large to be analysed by direct methods. This serious drawback is shared with many other modeling formalisms and is usually referred to as state space explosion. Usually simulation can be employed to analyse such models. An alternative is to restrict the SPN formalism to product-form SPNs, a class of nets whose unnormalised stationary probability distribution can be obtained in closed form, making stationary analysis much simpler. In this thesis we present algorithms for stationary analysis of SPN models based on efficient encoding of state spaces and transition functions by multi-valued decision diagrams, an efficient data structure. After a short introduction to SPNs and their steady-state analysis, we start with simulation of SPNs and present an algorithm for perfect sampling of SPNs that can be used to directly obtain samples from the stationary distribution. After this, we turn to product-form SPNs and present an algorithm for computation of normalising constant, needed for the normalisation of stationary probabilities in the analysis of product-form models.