Scalable and Privacy-Focused Company-Centric Supply Chain Management

Blockchain technology promises to overcome trust and privacy concerns inherent to centralized information sharing. However, current decentralized supply chain management systems do either not meet privacy and scalability requirements or require a …

The Road to Accountable and Dependable Manufacturing

In this article, we emphasize the need for further active research at the intersection of the Internet of Things, cyber-physical systems, and blockchain technology to benefit highly dynamic industrial networks and collaborations, e.g., the Industrial Internet of Things or flexible supply chains.

CoinPrune: Shrinking Bitcoin's Blockchain Retrospectively

In this paper, we present the full design of CoinPrune, our block-pruning protocol that is retrofittable to Bitcoin via a velvet fork. This work extends our initial paper presented at IFIP Networking 2020 by enabling CoinPrune to obfuscate most objectionable content stored in the UTXO set and introducing an additional store for application-level data. Furthermore, we extend our security discussion, our discussion of related work, we updated our performance evaluation, and we released a prototype implementation of CoinPrune. #

How to Securely Prune Bitcoin's Blockchain

This paper presents CoinPrune, a protocol for block pruning that is fully compatible to Bitcoin and therefore allows for gradual deployment. CoinPrune allows joining nodes to bootstrap using a state, which has been advertised on the blockchain recently, instead of having to download and verify all blockchain data. We maintain Bitcoin compatiblity by implementing CoinPrune as a velvet fork, i.e., instead of rejecting invalid state advertisements, we solely rely on positive state reaffirmations by multiple miners. Our evaluation shows users can reduce their synchronization times from 5 hours to 46 minutes using CoinPrune, while downloading only 5 GiB instead of 230 GiB of blockchain data as of October 2019.

Smart Contract-based Car Insurance Policies

Processes in the insurance economy are often cumbersome and expensive because of the inherently opposing interests of insurers and customers. Smart contracts bear a large potential to simplify these processes and thereby reduce costs. In this paper, …

Thwarting Unwanted Blockchain Content Insertion

Since the insertion of illicit content into public blockchains can have severe consequences for users, we explore and discuss the design space for preventing this insertion. Our findings show that firewall-like scanning of Bitcoin transactions poses no viable solution to the problem. However, while content insertion cannot entirely be prevented by technical means, self-verifying blockchain identifiers make currently simple manipulations hard. Finally, the introduction of mandatory minimum fees can be used to disincentivize content insertion additionally.