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Blockchain: a new framework for swarm RObotic Systems

Periodic Reporting for period 2 - BROS (Blockchain: a new framework for swarm RObotic Systems)

Reporting period: 2019-09-01 to 2020-08-31

Swarm robotics systems have the potential to revolutionize many future applications, such as transportation systems and targeted material delivery. However, several of the characteristics that make them ideal for a diverse set of applications also hinder the evolution of this technology from academia to real-world problems. BROS alerts about the lack of security standards in the field and suggests that before this technology can be safe, reliable, and trustworthy, new protocols and solutions need to be developed. Blockchain, demonstrates that by combining peer-to-peer networks with cryptographic algorithms, a group of agents can reach a consensus on a particular state of affairs without a centralized entity. Our initial discoveries show that beyond financial applications (i.e. cryptocurrencies) blockchain-based technology can be an effective way to achieve tamper-resistant, secure data-sharing systems. In a nutshell, the combination of blockchain with swarm robotics systems, provides the necessary capabilities to make these systems more secure, autonomous, flexible and even profitable.
"The aim of BROS during its first two years (outgoing phase) has been to explore the combination of blockchain technology with swarm robotics systems (from a theoretical point of view) and provide innovative solutions to three emergent issues in the field of swarm robotics. First, by using cryptographic functions, new security models and methods were implemented in order to give data confidentiality and entity validation to swarm robotics systems, therefore making them suitable for trust-sensitive applications. Second, by including code-based transactions (a.k.a. smart contracts), novel consensus and collaborative missions were easily designed, implemented, and carried out autonomously by robot swarms. Third, by using robots as nodes in a blockchain network, new methods for achieving a secure data-sharing among robots was achieved, something especially important as these systems become increasingly integrated into human society. Finally, in the project’s final year (incoming phase), BROS focused on the real-robot implementation of the solutions mentioned previously. In particular, we designed and conducted extensive real-world experiments (using a real-robot swarm) to show the feasibility of combining real-hardware robots with blockchain technology.

The main scientific achievements accomplished are the following:

(1) A novel method to encapsulate cooperative robotic missions by using Merkle trees (a fundamental technology in the blockchain space). With the proposed method, swarm operators can provide the “blueprint” of the swarm’s mission without disclosing its raw data. In other words, data verification can be separated from data itself. In the paper titled ""Secure and secret cooperation of robotic swarms by using Merkle trees"" (currently under review), we describe both theoretical and implementation approaches for this new model to achieve secure and secret cooperation within swarms of robots.

(2) The design, analysis and implementation of the first research projects that combines swarms of robots with blockchain-based “smart contracts” in order to discover malicious robot units (i.e. byzantine agents) within the swarm. In ""Managing Byzantine Robots via Blockchain Technology in a Swarm Robotics Collective Decision Making Scenario"" (AAMAS, 2018) and ""Blockchain Technology Secures Robot Swarms: A Comparison of Consensus Protocols and Their Resilience to Byzantine Robots"" (Frontiers in Robotics and AI, 2020), we provided a proof-of-concept for distributed decision-making processes in swarm robotics systems via blockchain technology. Our approach uses decentralized programs executed via blockchain technology (blockchain-based smart contracts) to establish secure swarm coordination mechanisms to reach group consensus but also to identify and exclude Byzantine swarm members.

(3) The simulation and analysis of several ""real-world"" robotic systems such as Autonomous Vehicles (AV), Unmanned Aerial Vehicles (UAV), and Social Robots (SR) and its interaction with blockchain-based technology. In ""BASIC: Towards a Blockchained Agent-Based SImulator for Cities"" (MMAS 2018), ""Robotic Services for New Paradigm Smart Cities Based on Decentralized Technologies"" (Ledger, 2019) and ""RoboChain: A Secure Data-Sharing Framework for Human-Robot Interaction"" (eTELEMED, 2018), we simulated and analyzed several blockchain-based models developed in the aforementioned objectives in combination with ""realistic"" robotic systems. The aim of these works was to study the feasibility and shed light on the use of blockchain-based technology together with robots that interact with human beings at different levels.

Exploitation and dissemination:

In order to maximize the exposure and dissemination of the aforementioned works we have organized three academic events during the project's duration: one workshop and two symposiums. Specifically, in July 2018, we organized the workshop on Blockchain Networks and Information Flow during the International Conference on Complex Systems (ICCS 2018). Complementarily, we organized and hosted the first and second symposiums on Blockchain for RObotic Systems (BROS) at the MIT Media Lab in 2018 and 2019. It is important to note that these two symposiums became the main events for the emergent academic community interested in the field of blockchain for robotic systems."
"After the completion of BROS, the project has made significant progress beyond the state of the art in several fronts. First, we are confident that by using blockchain-based technology, swarm robotics systems can achieve new cooperative and collaborative dynamics. For instance, cryptographic tools (e.g. Merkle trees) previously confined in other fields of research, can make swarms of robots cooperate without having explicit knowledge about its common mission’s high-level goals or objectives. In other words, by using these cryptographic tools, robots are now able to separate data verification from data itself which has important implications to achieve secure robotic swarm systems. Second, we are positive that blockchain-based ''smart contracts'' are a viable solution to handle distributed-decision making processes in swarm robotics systems. This insight sheds light on a complete new way to control and command a swarm of robots and interact with it. Finally, a careful analysis of ""real-world"" robots such as Unmanned Aerial Vehicle (UAVs), Autonomous Vehicles (AVs), Social Robots (SRs), etc. has shown that its combination with blockchain-based technology has benefits on the verification, validation, and security aspects of these autonomous systems, which opens the path towards more secure, autonomous, flexible and even profitable."
Poster of the MIT BROS 2019 Symposium
Poster of the MIT BROS 2018 Symposium