Overview of Polkadot and its Design Considerations

In this paper we describe the design components of the heterogenous multi-chain protocol Polkadot and explain how these components help Polkadot address some of the existing shortcomings of blockchain technologies. At present, a vast number of blockchain projects have been introduced and employed with various features that are not necessarily designed to work with each other. This makes it difficult for users to utilise a large number of applications on different blockchain projects. Moreover, with the increase in number of projects the security that each one is providing individually becomes weaker. Polkadot aims to provide a scalable and interoperable framework for multiple chains with pooled security that is achieved by the collection of components described in this paper

Seguridad en el enrutamiento utilizando tecnología Blockchain

Para realizar una ataque de route hijacking no se saca provecho a ninguna vulnerabilidad o falla de protocolo, sino que se explota que la arquitectura de BGP está basada en la confianza mutua. Por este motivo es que estos ataques son tan antiguos como el mismo protocolo, y en la actualidad estos fallos se siguen produciendo y se continúa investigando cual es la mejor estrategia para brindar seguridad al ruteo en Internet. Las nuevas soluciones, como RPKI, están generando riesgos debido a la centralización de la autoridad de enrutamiento, las mismas no se basan en la confianza mutua, pero dependen de la confianza en la autoridad. Con este trabajo se busca implementar un modelo menos centralizado, basado en blockchain, donde mediante el despliegue de una aplicación específica para la asignación de recursos de Internet en la red Ethereum Sepolia, y la posterior utilización de esa información almacenada, se demuestra como brindar seguridad al protocolo BGP.Asesor científico: Miguel A. MorandiFacultad de Informátic

Refinement and verification of CBC casper

Decentralised ledgers are a prime application case for consensus protocols. Changing sets of validators have to agree on a set of transactions in an asynchronous network and in the presence of Byzantine behaviour. Major research efforts focus on creating consensus protocols under such conditions, with proof-of-stake (PoS) representing a promising candidate. PoS aims to reduce the waste of energy inherent to proof-of-work (PoW) consensus protocols. However, a significant challenge is to get PoS protocols "right", i.e. ensure that they are secure w.r.t. safety and liveness. The "Correct-by-Construction" (CBC) Casper approach by the Ethereum project employs pen-and-paper proofs to ensure its security. CBC Casper is a framework to define consensus protocols and aims to prove safety without loss of abstractness. Each member of the CBC Casper family of protocols is defined by five parameters. CBC Casper models the protocol by a state of each validator and messages sent by validators. Each validator can transition its state using messages by other validators that include their current consensus value and a justification (i.e. their previous messages). We extend CBC Casper in three ways. First, we summarise the research of CBC Casper and extend the definitions of safety and liveness properties. To this end, we discuss an instance of CBC Casper called Casper The Friendly GHOST (TFG), a consensus protocol using a variant of the GHOST fork-choice rule. Second, we refine the properties of messages and states in CBC Casper and give a definition of blockchain safety for Casper TFG. Third, we formally verify the CBC Casper framework together with our refined message and state properties as well as our blockchain safety definition in the Isabelle/HOL proof assistant