Featured Publications

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IEEE ICBC 2019

One central promise of blockchain systems is to mediate interactions of mutually distrusting parties without the need for a trusted third party. SmartJudge is our lightweight framework to extend existing two-party protocols such as fair exchange or cross-blockchain trades with a conditional dispute resolution procedure. The rationale behind SmartJudge is that honest parties can jointly execute a protocol at minimal costs, and simultaneously are fully protected via a conditionally callable verifier smart contract in case of a dispute.
PDF Code DOI IEEE Xplore
BTA 2018

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.
PDF DOI IEEE Xplore Website
FGCS 80:448-466

CoinParty is a fully decentralized and thus secure Bitcoin mixing service. Our work uses threshold cryptography to combine the adavantages of centralized and decentralized mixers: high usability and strong security guarantees.
PDF Code DOI
FC’18

We survey methods enabling the insertion of arbitrary content into Bitcoin’s blockchain, quantitatively analyze their utilization, both directly and via content insertion services, and assess potential consequences of being forced to keep potentially illicit content on the users’ hard disks. Our findings show that arguably objectionable content has already been inserted to Bitcoin’s blockchain and that it can lead to legal liability for users in jurisdictions such as Germany.
PDF DOI The Morning Paper Website

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Journal Reviews

  • 2019: PETs (Privacy Enhancing Technologies Symposium)
  • 2019: Frontiers in Blockchain
  • 2018: Pervasive and Mobile Computing
  • 2017: Future Generation Computer Systems
  • 2015: Transactions on Wireless Communications

External Reviews

  • 2019: IEEE Blockchain (International Conference on Blockchain)
  • 2018: IEEE Blockchain (International Conference on Blockchain)

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  • 2018: IEEE TMA (Network Traffic Measurement and Analysis Conference)

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