Algorithms and Mechanisms for Blockchain

区块链是一种存储信息的分布式账本。它与传统数据库的主要区别在于它是分散的，这意味着它不是由中央机构管理，而是由其用户管理，并且它是无许可的，这意味着它对每个人都是可访问的。在过去的几年里，区块链领域受到了来自计算机科学、运筹学和金融等各个领域的大量科学关注。参与区块链网络的用户通常采取策略性行动，试图最大化他们的利润。我们的主要目标是研究和设计区块链上的新机制，以满足某些博弈论保证。区块链的去中心化性质要求修改当前已知的机制或从头开始设计新的机制。区块链由大量用户组成，因此实现的机制和算法应该在时间上是有效的。在某些情况下，满足所有上述约束的这种机制的设计是不可能的，因此，我们需要放松其中一些约束，我们将研究所产生的权衡。在这种情况下，将使用近似算法。此外，我们有兴趣应用机器学习技术，如强化学习和深度学习，以检查区块链协议的安全性。我们将研究可应用于不同区块链网络的机制，但特别是我们将集中在Tezos网络。Tezos是使用权益证明共识协议的现代区块链之一，区别它的属性是自我修正。自我修正属性允许网络通过多阶段过程进行升级。Tezos网络的这些方面为分析用户的动机提供了富有成效的基础。因此，我们未来的目标之一是在Tezos网络中提出并实施新的修改。

Blockchain is a distributed ledger that stores information. Its primary difference from a conventional database is that it is decentralised, which means it is not managed by a central authority but by its users and it is permissionless which means that it is accessible to everyone. The last years, the field of blockchain has tracked a lot of scientific attention from various fields such as computers science, operational research and finance. Users that participate in blockchain networks usually act strategic, trying to maximize their profit.Our primary goal is to study and design novel mechanisms on blockchain that satisfy certain game-theoretic guarantees. The decentralised nature of blockchain mandates to modify the current known mechanisms or design new from scratch. Blockchains are consisted of a large number of users and therefore the mechanisms and algorithms implemented should to be efficient in time. The design of such mechanism that satisfy all the above constraints, in some cases will be impossible and thus, we will need to relax some of those constraints and we will examine the incurred trade-offs. In this case, approximation algorithms will be used.Moreover, we are interested in applying machine learning techniques such as reinforcement learning and deep learning in order to examine the safety of blockchain protocols.We will study mechanisms that can be applied on different blockchain networks but in particular we will concentrate on Tezos network. Tezos is one of the modern blockchains which uses a Proof-of-Stake consensus protocol and the property that distinguishes it, is the self-amendment. The self-amendment property allows the network to upgrade through a multi-stage process. These aspects of Tezos network provide fruitful ground for analysis regarding the incentives of the users.Thus, one of our future goals is to propose and implement new amendments in Tezos network.