Bitcoin meets strong consistency

The Bitcoin system only provides eventual consistency. For everyday life, the time to confirm a Bitcoin transaction is prohibitively slow. In this paper we propose a new sys-tem, built on the Bitcoin blockchain, which enables strong consistency. Our system, PeerCensus, acts as a certifica-tion authority, manages peer identities in a peer-to-peer network, and ultimately enhances Bitcoin and similar sys-tems with strong consistency. Our extensive analysis shows that PeerCensus is in a secure state with high probability. We also show how Discoin, a Bitcoin variant that decouples block creation and transaction confirmation, can be built on top of PeerCensus, enabling real-time payments. Unlike Bitcoin, once transactions in Discoin are committed, they stay committed

Resolution of Blockchain Conflicts through Heuristics-based Game Theory and Multilayer Network Modeling

A blockchain is a fully distributed system in which the user behavior, actions and decisions are crucial for its operation. This paper discusses how to handle conflict situations affecting a blockchain system. Specifically, we model two real-world conflict scenarios – the Lazy Miner dilemma and the Impatient Seller dilemma – by proposing a novel multi-layer framework coupled with a heuristicsbased game-theoretic modeling. The multi-layer approach provides a way to include cross-modality integration (human quality factors, such as reliability) and human actions on the blockchain. We design a multi-agent game-theoretic methodology combined with some statistical estimators derived from the heuristics. Our model also includes the concept of homophily, a human-related factor connected to the similarity and frequency of interactions on the multi-layer network. Based on the heuristics, a dynamically evolving measure of weights is further defined such that an agent increases or decreases the link weights to its neighbours according to the experienced payoffs. We show how data mining in blockchain data could be incorporated into a heuristic model which provides parameters for the game-theoretic payoff matrix. Thus, this work represents a platform for simulating the evolutionary dynamics of the agents’ behaviors, including also heuristics and homophily on a multi-layer blockchain network