1st Scientific School on Blockchain and Distributed Ledger Technologies

posted Mar 15, 2018, 6:45 AM by Massimo Bartoletti

1st Scientific School on Blockchain and Distributed Ledger Technologies
Pula, Sardinia, Italy
12-15 June 2018

Crypto economics is a new discipline born after the rise of virtual currencies and distributed ledger technologies, and is rapidly developing in a unique intersection between computing, cryptography, law, economics, and game theory. The school aims at disseminating knowledge about the foundations and the applications of these technologies to researchers, PhD students, scholars and technologists in industry and academia, not excluding under- or new graduates with strong technical drive and a sufficient background.


The school will be hosted at the Technology Park of Sardinia in Pula (Sardinia, Italy).
Travel and accommodation information are available on the school website.


The registration and attendance is FREE of charge. However, as we may not be able to accommodate all the applicants, the attendees will be selected by the scientific committee on a CV best-match basis. This implies that candidates showing the attitude to receive the most value from the lectures will be given higher priority. The school plans for a maximum of 38 attendees with a quota of 12 seats reserved to scholars coming from CRS4, University of Cagliari and from SMEs located in Sardinia. Should this quota remain unfilled, the remainder seats will be redistributed to waitlisted participants.


Prospective participants should apply through the school web page by April 15, 2018
Notification of accepted applicants will be posted by April 31, 2018
School dates June 12-15, 2018

  • Silvio Micali (MIT). Algorand: a truly distributed ledger
  • Paolo Tasca (UCL). TBA
  • Rainer Böhme (Univ. Innsbruck). Incentives Matter: On the Economics and Governance of Blockchain-based Systems
  • Stefano Bistarelli (Univ. Perugia). From mining to multisigned transactions: discovering how Bitcoin works
  • Massimo Simbula. Bitcoin revolution a legal perspective
  • Michele Nati (Digital Catapult). Reputation and personal data in the blockchain age
  • Federico Tenga (Chainside). Bitcoin Scalability, payment channels and lightning networks
  • Michele Marchesi (Univ. Cagliari). Software engineering methodologies for blockchain development
  • Davide Carboni (CRS4). Introduction to Ethereum and smart contracts
  • Mauro Pili (Paymeabit). Web3: a platform for decentralized apps
  • Massimo Bartoletti, Livio Pompianu,Alessandro Sebastian Podda, Nicola Atzei (Univ. Cagliari). Hands on lab on Bitcoin
  • Mauro Pili, Andrea Pinna, Marco Ortu, Simona Ibba (Univ. Cagliari). Hands on lab on Ethereum

  • Massimo Bartoletti, University of Cagliari
  • Davide Carboni, CRS4 Pula (chair)
  • Salvatore Carta, University of Cagliari
  • Rocco De Nicola, IMT Lucca
  • William Knottenbelt, Imperial College of London
  • Michele Marchesi, University of Cagliari
  • Francesco Piras, Associazione Bitcoin Sardegna

Upcoming paper: SoK: unraveling Bitcoin smart contracts

posted Mar 1, 2018, 2:34 PM by Massimo Bartoletti

Upcoming paper (to be presented at POST 2018)

Nicola Atzei, Massimo Bartoletti, Tiziana Cimoli, Stefano Lande, Roberto Zunino

Abstract. Albeit the primary usage of Bitcoin is to exchange currency, its blockchain and consensus mechanism can also be exploited to securely execute some forms of smart contracts. These are agreements among mutually distrusting parties, which can be automatically enforced without resorting to a trusted intermediary. Over the last few years a variety of smart contracts for Bitcoin have been proposed, both by the academic community and by that of developers. However, the heterogeneity in their treatment, the informal (often incomplete or imprecise) descriptions, and the use of poorly documented Bitcoin features, pose obstacles to the research.

In this paper we present a comprehensive survey of smart contracts on Bitcoin, in a uniform framework. Our treatment is based on a new formal specification language for smart contracts, which also helps us to highlight some subtleties in existing informal descriptions, making a step towards automatic verification. We discuss some obstacles to the diffusion of smart contracts on Bitcoin, and we identify the most promising open research challenges.

Upcoming paper: A formal model of Bitcoin transactions

posted Dec 5, 2017, 7:03 AM by Massimo Bartoletti   [ updated Mar 1, 2018, 2:35 PM ]

Upcoming paper (to be presented at Financial Cryptography 2018)

Nicola Atzei, Massimo Bartoletti, Stefano Lande, Roberto Zunino

We propose a formal model of Bitcoin transactions, which is sufficiently abstract to enable formal reasoning, and at the same time is concrete enough to serve as an alternative documentation to Bitcoin. We use our model to formally prove some well-formedness properties of the Bitcoin blockchain, for instance that each transaction can only be spent once. We release an open-source tool through which programmers can write transactions in our abstract model, and compile them into standard Bitcoin transactions.

Upcoming paper: A general framework for blockchain analytics

posted Oct 23, 2017, 9:13 AM by Massimo Bartoletti

Upcoming paper (to be presented at SERIAL 2017)
Massimo Bartoletti, Andrea Bracciali, Stefano Lande, Livio Pompianu

Abstract. Modern cryptocurrencies exploit decentralised blockchains to record a public and unalterable history of transactions. Besides transactions, further information is stored for different, and often undisclosed, purposes, making the blockchains a rich and increasingly growing source of valuable information, in part of difficult interpretation. Many data analytics studies have been carried out, mostly based on specifically designed and ad-hoc engineered approaches. We propose a general-purpose framework, seamlessly supporting data analytics on both Bitcoin and Ethereum — currently the two most prominent cryptocurrencies. Such a framework allows us to integrate relevant blockchain data with data from other sources, and to organise them in a database, either SQL or NoSQL. Our framework is released as an open-source Scala library, a mainstream Java-like programming language. We illustrate the distinguishing features of our approach on a set of significant use cases, which allow us to empirically compare ours to other competing proposals, and evaluate the impact of the database choice on scalability.

Upcoming paper: Timed Session Types

posted Oct 23, 2017, 9:09 AM by Massimo Bartoletti

Upcoming paper (to appear in LMCS)
Massimo Bartoletti, Tiziana Cimoli, Maurizio Murgia

Timed session types formalise timed communication protocols between two participants at the endpoints of a session. They feature a decidable compliance relation, which generalises to the timed setting the progress-based compliance between untimed session types. We show a sound and complete technique to decide when a timed session type admits a compliant one. Then, we show how to construct the most precise session type compliant with a given one, according to the subtyping preorder induced by compliance. Decidability of subtyping follows from these results.

Seminar: On the Security of the Blockchain Bix Protocol and Certificates

posted Oct 6, 2017, 8:25 AM by Sebastian P.   [ updated Oct 6, 2017, 8:26 AM ]

Upcoming Seminar

 On the Security of the Blockchain Bix Protocol and Certificates

October 5, 15.00 (Aula F)
Palazzo delle Scienze - Cagliari

Riccardo Longo

University of Trento (IT)

Abstract: The BIX protocol is a blockchain-based protocol that allows distribution of certificates linking a subject with his public key, hence providing a service similar to that of a PKI but without the need of a CA. In this seminar I will present an analysis of the security of the BIX protocol in a formal way. First, I will identify formal security assumptions which are well-suited to this protocol. Second, I will present some attack scenarios against the BIX protocol. Finally, I will provide a formal security proof that these attacks are not feasible under our previously established assumptions.

Seminars series: cryptocurrencies and smart contracts 2017

posted Apr 18, 2017, 3:16 AM by Massimo Bartoletti

The preliminary programme of this series of seminars is available here.

Seminar: Behavioural type-checking of time-sensitive protocols

posted Apr 18, 2017, 2:57 AM by Massimo Bartoletti   [ updated Apr 18, 2017, 3:31 AM ]

Upcoming Seminar

Behavioural type-checking of time-sensitive protocols

April 21, 15.00 (Aula F)
Palazzo delle Scienze - Cagliari

Laura Bocchi

University of Kent (UK)

Abstract. In recent work we have extended multiparty session types (MPST) with a model of time borrowed from Communicating Time Automata (CTA). This allowed us to establish a sound and complete correspondence between timed MPST and a subclass of CTA that satisfies progress. On the basis of this correspondence, we can decide properties on CTA that are undecidable in the general case, such as safety (absence of orphan messages and communication mismatches), progress, non-zenoness and eventual reception of messages sent. I will present decidable conditions for these properties, and   give a concrete procedure to build *when possible* global timed MPST from (arbitrary) collections of timed automata, with the guarantee that the resulting global specification is a well-behaved composition.


Upcoming paper: An empirical analysis of smart contracts: platforms, applications, and design patterns

posted Mar 24, 2017, 1:49 PM by Massimo Bartoletti

Upcoming paper (to be presented at WTSC 2017)
Massimo Bartoletti and Livio Pompianu

Smart contracts are computer programs that can be consistently executed by a network of mutually distrusting nodes, without the arbitration of a trusted authority. Because of their resilience to tampering, smart contracts are appealing in many scenarios, especially in those which require transfers of money to respect certain agreed rules (like in financial services and in games). Over the last few years many platforms for smart contracts have been proposed, and some of them have been actually implemented and used. We study how the notion of smart contract is interpreted in some of these platforms. Focussing on the two most widespread ones, Bitcoin and Ethereum, we quantify the usage of smart contracts in relation to their application domain. We also analyse the most common programming patterns in Ethereum, where the source code of smart contracts is available.

Upcoming paper: An analysis of Bitcoin OP_RETURN metadata

posted Mar 24, 2017, 1:44 PM by Massimo Bartoletti

Upcoming paper (to be presented at BITCOIN 2017)
Massimo Bartoletti and Livio Pompianu

The Bitcoin protocol allows to save arbitrary data on the blockchain through a special instruction of the scripting language, called OP_RETURN. A growing number of protocols exploit this feature to extend the range of applications of the Bitcoin blockchain beyond transfer of currency. A point of debate in the Bitcoin community is whether loading data through OP_RETURN can negatively affect the performance of the Bitcoin network with respect to its primary goal. This paper is an empirical study of the usage of OP_RETURN over the years. We identify several protocols based on OP_RETURN, which we classify by their application domain. We measure the evolution in time of the usage of each protocol, the distribution of OP_RETURN transactions by application domain, and their space consumption.

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