Category Archives: Acadia seminar series

14/09/2016 – Talk by prof. Jia Yuan Yu (Concordia Institute of Information System Engineering)

Title: Central-Limit Approach to Risk-aware Markov Decision Processes
Time: 14:00
Location: Meeting room
Type: Research Result
Speaker: Jia Yuan Yu
Abstract: Whereas classical Markov decision processes maximize the expected reward, we consider minimizing the risk. We propose to evaluate the risk associated to a given policy over a long-enough time horizon with the help of a central limit theorem. The proposed approach works whether the transition probabilities are known or not. We also provide a gradient-based policy improvement algorithm that converges to a local optimum of the risk objective.

07/09/2016 – Talk by Mohsin Jafri

Title:  Simulating Depth-based routing in Underwater Networks
Time: 13:45
Location: Meeting room
Type: Research Result
Speaker: Mohsin Jafri
Abstract: In this talk, I will briefly discuss my ongoing research activities. I will present the implementation of a simulator for
studying Depth-Based Routing (DBR) in Underwater Wireless Sensor Networks (UWSNs). One of the major challenges for DBR is the configuration of a parameter called “holding time” which influences the network throughput, response time and energy consumption. I will show how it is possible to use the simulator to support the validation of a choice for a given value of the holding time, as well as other network parameters. The presentation will also discuss the important features that distinguish the implemented simulator with respect to the other ones available in the scientific literature and its validation against previous simulation models or measurements.

07/09/2016 – Talk by Francesco di Giacomo

Title:  Building Domain Specific Languages with the Metacasanova meta-compiler
Time: 14:00
Location: Meeting room
Type: Research Result
Speaker: Francesco di Giacomo
Abstract: main specific languages (DSL’s) are becoming more popular thanks to their ability to provide abstractions that are not part of general purpose languages that ease the development process in specific scenarios, ranging from video games to web development.
Creating a new DSL requires to build a compiler for it, which is a very complex piece of software. This complexity usually causes two problems: (i) the development of the compiler itself requires a significant amount of manpower, and (ii) adding new features to the language may become problematic. In this talk we propose a different approach to writing a hard-coded compiler by using a meta-compiler, i.e. a software that takes as an input the language definition and a program written in that language, and outputs a corresponding executable code. We show the advantages of this approach in terms of simplicity of design and coding requirements, and we present a performance analysis on the generated code for Casanova 2, a DSL for game software development.

27/07/2016 – Talk by Enrico Steffinlongo

Title:  Efficent Static Detection of Collusion Attacks in ARBAC-based Workflow Systems
Time: 14:45
Location: Acadia Lab
Type: Research Result
Speaker: Enrico Steffinlongo
Authorization in workflow systems is usually built on top of role-based access control (RBAC); security policies on workflows are then expressed as constraints on the users performing a set of tasks and the roles assigned to them. Unfor-tunately, when role administration is distributed and potentially untrusted users contribute to the role assignment process, like in the case of Administrative RBAC (ARBAC), collusions may take place to circumvent the intended workflow security policies. In a collusion attack, a set of users of a workflow system collaborates by changing the user-to-role assignment, so as to sidestep the security policies and run up to completion a workflow they could not complete otherwise.
In this paper, we study the problem of collusion attacks in a formal model of workflows based on stable event structures and we define a precise notion of security against collusion. We then propose a static analysis technique based on a reduction to a role reachability problem for ARBAC, which can be used to prove or disprove security for a large class of workflow systems. We also discuss how to aggressively optimise the obtained role reachability problem to ensure its tractability. Finally, we implement our analysis in a tool, WARBAC, and we experimentally show its effectiveness on a set of publicly available examples, including a realistic case study.

27/07/2016 – Talk by Marco Squarcina

Title:  Relation on ongoing PhD program
Time: 14:00
Location: Acadia Lab
Type: Research Result
Speaker: Marco Squarcina

The aim of this talk is to briefly report on my ongoing research activities. After presenting the accepted and in-progress papers, I will focus on the results achieved during the internship at Cryptosense in Paris where I carried out the analysis of several Java keystores (storage facilities for cryptographic keys and certificates) exposing
design and implementation weaknesses. I am currently investigating on the cracking-resistance of the keystores against brute force attacks and I plan to support my findings by implementing password cracking plugins for popular tools such as jtr or hashcat.

23/03/2016 – Talk by Renzo Derosas

Title:  Modelling a Demographic Suicide: the Venetian Aristocracy, 1500 to 1800.
Time: 14:30
Location: Meeting room, building Zeta
Type: Research Result
Speaker: Renzo Derosas
BACKGROUND: Around 1500, the Republic of Venice was a leading European power, ruling over an empire that stretched from the current Swiss and Austrian borders on the north, all along the Adriatic coast, to the islands of Cyprus and Crete in the southeast. Although its political regime was celebrated as a mix a democratic, aristocratic, and monarchical features, political power was the monopoly of a limited number of aristocratic families who passed it on from generation to generation. Indeed, Venice was defined “a republic of families”, whose destinies were fully identified with the State they belonged to. On the one hand, the very survival of the Republic depended on the reproduction – demographic, economic, and cultural – of its ruling class; on the other hand, there was hardly a place for the Venetian nobility without the State that supported its privileged status.
The number of aristocratic families grew from ca. 600 in 1400 to a maximum of 900 in 1500, and then declined steadily to a low of 350 at the fall of the Republic (1797). Correspondingly, the noblemen grew from 900 in 1400 to 2,650 in 1500, to fall to 1,100 in 1797. Although contemporaries were aware of the problems deriving from such a trend, all efforts to invert it turned out ineffective. Historians agree that the decline originated in the peculiar marriage policy adopted by the aristocracy: once Venetian nobles converted from merchants into landowners, they allowed only one male per generation to marry. They were obsessed with keeping their assets undivided, since any branching out would jeopardize their social and political standing. Unfortunately, the outcome was disastrous under both the demographic and the economic standpoints. At the fall of the Republic, due to the hazards of reproduction, almost two thirds of the families extinguished, while most of the survivors were heavily impoverished.

OBJECTIVES: With this research project, we challenge the current interpretation of the demographic decline of the Venetian aristocracy. We argue that it is incomplete, inasmuch it does not consider that many noblemen rather remained single than marry, condemning their families to extinction. Such a behavior was deeply contrary to the ethics and the ideology of the aristocracy. How can we explain it? Our aim is to develop a theory that accounts for both the decision to marry or not to marry.

METHODS: Our starting point is the assumption that marital choices in the Venetian aristocracy were primarily a political option, undertaken to enhance a family’s position in the political arena through the acquisition of new kin. More specifically, we hypothesize that, when it came to establish a new and lasting alliance through the marriage of their members, families strove to maximize their relational capital they would acquire. Our related hypothesis is that when the advantage deriving from all potential matches was below a certain threshold, a family would rather abstain from joining the market.
Although the strategic importance of marital choices by the Venetian aristocracy is largely circulating in the literature, the evidence provided thus far was only anecdotal and rather loosely defined. To test our hypothesis, we proceed in a tentative and exploratory way. Since we have only a list of the marriages celebrated along time but not of the population at risk, we define a set of potential partners made up by all those who married in the same year. We then outline the potential ego-networks formed by each match, and compute a series of centrality measures associated to each ego-network. Finally, we run a logistic regression to test whether any of such measures affects the likelihood of a match.

09/03/2016 – Talk by Stefano Calzavara

Title:  HornDroid: Practical and Sound Static Analysis of Android Applications by SMT Solving
Time: 13:30
Location: Meeting room, building Zeta
Type: Research Result
Speaker: Stefano Calzavara
We present HornDroid, a new tool for the static analysis of information flow properties in Android applications. The core idea underlying HornDroid is to use Horn clauses for soundly abstracting the semantics of Android applications and to express security properties as a set of proof obligations that are automatically discharged by an off-the-shelf SMT solver. This approach makes it possible to fine-tune the analysis in order to achieve a high degree of precision while still using off-the-shelf verification tools, thereby leveraging the recent advances in this field. As a matter of fact, HornDroid outperforms state-of-the-art Android static analysis tools on benchmarks proposed by the community. Moreover, HornDroid is the first static analysis tool for Android to come with a formal proof of soundness, which covers the core of the analysis technique: besides yielding correctness assurances, this proof allowed us to identify some critical corner-cases that affect the soundness
guarantees provided by some of the previous static analysis tools for Android.

02/03/2016 – Talk by Filippo Cavallin

Title:  Cronization: a method to pass from Continuous Time to Discrete Time Automata
Time: 14:00
Location: Meeting room, building Zeta
Type: Research Result
Speaker: Filippo Cavallin
Discrete and Continuous Time automata are important formalisms to model and analyze systems such queuing and telecommunication networks. The stationary performance analysis of these automata requires the computation of the steady-state distribution of their underlying Markov chains. Sometimes for the analysis is more convenient to pass from continuous to discrete time. The main methods are focused on the underlying Markov chains and not on the automatas. To preserve the transitions with labels and the synchronization between them, we will introduce a method to pass from a continuous time stochastic automaton (SA) to a probabilistic Input/Output automaton (PIOA). This method is a bijection from continuous to discrete time and it allows us to switch between the two different types of automata and it preserves the parallel composition.

25/01/2016 – Talk by Pierpaolo Degano

Title:  Context-aware Security: Linguistic Mechanisms and Static Analysis
Time: 14:00
Location: Meeting room, building Zeta
Type: Research Result
Speaker: Pierpaolo Degano
Adaptive systems improve their efficiency by modifying their behaviour to respond to changes in their operational environment. Also, security must adapt to these changes and policy enforcement becomes dependent on the dynamic contexts. We study these issues within (the core of) an adaptive declarative language proposed recently. A main characteristic of this language is to have two components: a logical one for handling the context and a functional one for computing. We extend it with security policies that are expressed in logical terms. They are of two different kinds: context and application policies. The first, unknown a priori to an application, protect the context from unwanted changes. The others protect the applications from malicious actions of the context, can be nested and can be activated and deactivated according to their scope. An execution step can occur only if all the policies in force hold, under the control of an execution monitor. Beneficial to this is a type and effect system, which safely approximates the behaviour of an application, and a further static analysis, based on the computed effect. The last analysis can only be carried on at load time, when the execution context is known, and it enables us to efficiently enforce the security policies on the code execution, by instrumenting applications. The monitor is thus implemented within the language itself, and it is only activated on those policies that may be infringed and switched off otherwise.

Short bio
Pierpaolo Degano has been

  • since 1/11/1990 full Professore in computer science, since 1993 at Dipartimento di Informatica, Università di Pisa
  • 1993-96 head of the Dipartimento di Informatica, Università di Pisa
  • 2000-2003 Chairman of GRIN, the Italian Association of the Professors of Computer Science
  • since 2001 member of the scientific committee of the Scuola di Dottorato di Eccellenza “Galileo Galilei”, since 2009 vice-chairman
  • since 2006 head of the PhD programme in Computer Science
  • since 2007 chairman of the Italian Committee of PhD programmes in Computer Science
  • since 2005 member of the scientific committee of CoSBi, the Microsoft Research – University of Trento Centre for Computational and Systems Biology

22/01/2016 – Talk by Stefano Zanero

Title:  Making sense of a million samples per day: Behavior-based Methods for Automated, Scalable Malware Analysis
Time: 12:00
Location: Meeting room, building Zeta
Type: Research Result
Speaker: Stefano Zanero
With the astonishing rate of new and modified malware samples being released daily, automation of analysis is needed to classify and cluster together similar samples, exclude basic and uninteresting variations, and focus costly manual analysis work on novel and interesting features (e.g., added or remove pieces of code with a given semantic). We will discuss the challenges in analyzing large malware datasets in a (semi)automatic fashion, and some recent research results that may help with the task, by leveraging the concept of “behavior” applied to malicious code.
Short bio: Stefano Zanero is an associate professor at DEIB, the computer engineering department of the Politecnico di Milano University. His research interests focus on systems security, in particular automated malware analysis, cyber-phisical systems security, critical infrastructure security, as well as computer forensics.