Feather forking as a positive force: incentivising green energy production in a blockchain-based smart grid

Climate change represents a serious threat to the health of our planet and imposed a discussion upon energy waste and production. In this paper we propose a smart grid architecture relying on blockchain technology aimed at discouraging the production and distribution of non-renewable energy as the one derived from fossil fuel. Our model relies on a reverse application of a recently introduced attack to the blockchain based on chain forking. Our system involves both a central authority and a number of distributed peers representing the stakeholders of the energy grid. This system preserves those advantages derived from the blockchain and it also address some limitations such as energy waste for mining operations. In addition, the reverse attack we rely on allows to mitigate the behavior of a classic blockchain, which is intrinsecally self-regulated, and to trigger a sort of ethical action which penalizes non-renewable energy producers. Blacklisted stakeholders will be induced to provide their transaction with higher fees in order to preserve the selling rate

Securing Proof-of-Work Ledgers via Checkpointing

Our work explores mechanisms that secure a distributed ledger in the presence of adversarial mining majorities. Distributed ledgers based on the Proof-of-Work (PoW) paradigm are typically most vulnerable when mining participation is low. During these periods an attacker can mount devastating attacks, such as double spending or censorship of transactions. We put forth the first rigorous study of checkpointing as a mechanism to protect distributed ledgers from such 51% attacks. The core idea is to employ an external set of parties that assist the ledger by finalizing blocks shortly after their creation. This service takes the form of checkpointing and timestamping; checkpointing ensures low latency in a federated setting, while timestamping is fully decentralized. Contrary to existing checkpointing designs, ours is the first to ensure both consistency and liveness. We identify a previously undocumented attack against liveness, “block lead”, which enables Denial-of-Service and censorship to take place in existing checkpointed settings. We showcase our results on a checkpointed version of Ethereum Classic, a system which recently suffered a 51% attack, and build a federated distributed checkpointing service, which provides high assurance with low performance requirements. Finally, we fully decentralize our scheme, in the form of timestamping on a secure distributed ledger, and evaluate its performance using Bitcoin and Ethereum

Accountability in a Permissioned Blockchain: Formal Analysis of Hyperledger Fabric

While accountability is a well-known concept in distributed systems and cryptography, in the literature on blockchains (and, more generally, distributed ledgers) the formal treatment of accountability has been a blind spot: there does not exist a formalization let alone a formal proof of accountability for any blockchain yet. Therefore, in this work we put forward and propose a formal treatment of accountability in this domain. Our goal is to formally state and prove that if in a run of a blockchain a central security property, such as consistency, is not satisfied, then misbehaving parties can be identified and held accountable. Accountability is particularly useful for permissioned blockchains where all parties know each other, and hence, accountability incentivizes all parties to behave honestly. We exemplify our approach for one of the most prominent permissioned blockchains: Hyperledger Fabric in its most common instantiation

AUC: Accountable Universal Composability

Accountability is a well-established and widely used security concept that allows for obtaining undeniable cryptographic proof of misbehavior, thereby incentivizing honest behavior. There already exist several general purpose accountability frameworks for formal game-based security analyses. Unfortunately, such game-based frameworks do not support modular security analyses, which is an important tool to handle the complexity of modern protocols. Universal composability (UC) models provide native support for modular analyses, including re-use and composition of security results. So far, accountability has mainly been modeled and analyzed in UC models for the special case of MPC protocols, with a general purpose accountability framework for UC still missing. That is, a framework that among others supports arbitrary protocols, a wide range of accountability properties, handling and mixing of accountable and non-accountable security properties, and modular analysis of accountable protocols. To close this gap, we propose AUC, the first general purpose accountability framework for UC models, which supports all of the above, based on several new concepts. We exemplify AUC in three case studies not covered by existing works. In particular, AUC unifies existing UC accountability approaches within a single framework