Giulia Fanti

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Bio

Giulia Fanti is an Assistant Professor of Electrical and Computer Engineering at Carnegie Mellon University. Her research interests span the security, privacy, and efficiency of distributed systems. She is a two-time fellow of the World Economic Forum’s Global Future Council on Cybersecurity and a member of NIST’s Information Security and Privacy Advisory Board. Her work has been recognized with several awards, including best paper awards, a Sloan Fellowship, an Intel Rising Star Faculty Award, and an ACM SIGMETRICS Rising Star Award. She obtained her Ph.D. in EECS from U.C. Berkeley and her B.S. in ECE from Olin College of Engineering

Topic: Strategic Latency Reduction in Blockchain Peer-to-Peer Networks

Most permissionless blockchain networks run on peer-to-peer (P2P) networks, which offer flexibility and decentralization at the expense of performance (e.g., network latency). Historically, this tradeoff has not been a bottleneck for most blockchains. However, an emerging host of blockchain-based applications (e.g., decentralized finance) are increasingly sensitive to latency; users who can reduce their network latency relative to other users can accrue (sometimes significant) financial gains. In this work, we initiate the study of strategic latency reduction in blockchain P2P networks. We first define two classes of latency that are of interest in blockchain applications. We then show empirically that a strategic agent who controls only their local peering decisions can manipulate both types of latency, achieving 60% of the global latency gains provided by the centralized, paid service bloXroute, or, in targeted scenarios, comparable gains. Finally, we show that our results are not due to the poor design of existing P2P networks. Under a simple network model, we theoretically prove that an adversary can always manipulate the P2P network’s latency to their advantage, provided the network experiences sufficient peer churn and transaction activity

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Josie Baker

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Bio

Bitcoin Core contributor by day, privacy enthusiast by night. Particularly interested in the overlap of privacy and usability

Topic: The devil in the details: combining cryptographic protocols

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Tim Ruffing

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Bio

Tim is an applied cryptographer in the research team of Blockstream, a Bitcoin and blockchain technology company. He obtained his PhD from Saarland University, researching cryptographic aspects of cryptocurrencies. His current research focuses on advanced applications of Schnorr signatures, e.g., multisignatures and threshold signatures. Tim also serves a co-maintainer of libsecp256k1, the cryptographic open-source library used in Bitcoin Core

Topic: No More Guesswork: Ready-to-Use Distributed Key Generation for FROST

Threshold signature schemes such as FROST are gaining considerable attention in Bitcoin. Yet, Distributed Key Generation (DKG), with its heavy requirements on the underlying communication mechanisms such as secure channels and a secure broadcast mechanism, remains the Achilles heel of threshold signatures and holds back their deployment in the real world.
In this talk, we will first take a detailed look at the obstacles that implementers and practitioners face in practice. We will foster an understanding of potential pitfalls and attacks, in particular those that can arise from the (mis)use of reliable broadcast protocols. We will then provide recommendations and guidelines on how to avoid these pitfalls and implement broadcast securely in practice. A key technical ingredient in our recommendations is a simple extension of the Goldwasser-Bellare echo broadcast protocol, which we have not seen proposed in the context of DKG so far.
With these learnings in mind, we present ChillDKG, a DKG protocol that fully incorporates minimal but sufficient implementations of secure channels and reliable broadcast, and thereby hides this complexity from engineers entirely. The protocol addresses further practical problems by eliminating the need for fresh randomness per threshold setup and offering a practical solution for backups. To facilitate real-world adoption of ChillDKG, we have been working on a publicly available specification that aims to be comprehensive and easy to use

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Jonas Nick

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Bio

Jonas Nick is a researcher in the field of Bitcoin, working as part of Blockstream's research team. He has made contributions to the Bitcoin community through his involvement in co-authoring various Bitcoin Improvement Proposals (BIPs), including the Taproot BIPs. Additionally, Jonas has collaborated on several scientific publications in cryptography, such as MuSig2 and Bulletproofs++ and contributes to the secp256k1 cryptographic library

Topic: No More Guesswork: Ready-to-Use Distributed Key Generation for FROST

Threshold signature schemes such as FROST are gaining considerable attention in Bitcoin. Yet, Distributed Key Generation (DKG), with its heavy requirements on the underlying communication mechanisms such as secure channels and a secure broadcast mechanism, remains the Achilles heel of threshold signatures and holds back their deployment in the real world.
In this talk, we will first take a detailed look at the obstacles that implementers and practitioners face in practice. We will foster an understanding of potential pitfalls and attacks, in particular those that can arise from the (mis)use of reliable broadcast protocols. We will then provide recommendations and guidelines on how to avoid these pitfalls and implement broadcast securely in practice. A key technical ingredient in our recommendations is a simple extension of the Goldwasser-Bellare echo broadcast protocol, which we have not seen proposed in the context of DKG so far.
With these learnings in mind, we present ChillDKG, a DKG protocol that fully incorporates minimal but sufficient implementations of secure channels and reliable broadcast, and thereby hides this complexity from engineers entirely. The protocol addresses further practical problems by eliminating the need for fresh randomness per threshold setup and offering a practical solution for backups. To facilitate real-world adoption of ChillDKG, we have been working on a publicly available specification that aims to be comprehensive and easy to use

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Hannes Hartenstein

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Bio

Hannes Hartenstein is a professor for computer science at Karlsruhe Institute of Technology (KIT) in Karlsruhe, Germany, since 2003. He is heading a research group on decentralized systems and network services at KIT’s Institute of Information Security and Dependability (KASTEL)

Topic: From Monitoring Bitcoin to Verifying Lightning: Modeling Aspects of the Bitcoin Universe

We are monitoring the Bitcoin peer-to-peer network since 2015 and will report on some interesting observations and findings. Over the last years, this longitudinal monitoring study shows that the Bitcoin network is remarkably stable. However, we could also observe singular events that gave unique insights into the network's structure. We discuss what we know and what we do not know about the actual Bitcoin network and the corresponding quality of Bitcoin network models. Furthermore, we examine how to prove Lightning secure by formally modeling payment channels, assess the compatibility of corresponding first and second layer models, and close with some future research directions

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Matthias Grundmann

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Bio

Matthias Grundmann is a doctoral researcher at KIT. His research focuses on ways to better understand and improve the P2P network layer of Bitcoin as well as evaluating and improving payment channel networks as a second layer for blockchains

Topic: From Monitoring Bitcoin to Verifying Lightning: Modeling Aspects of the Bitcoin Universe

We are monitoring the Bitcoin peer-to-peer network since 2015 and will report on some interesting observations and findings. Over the last years, this longitudinal monitoring study shows that the Bitcoin network is remarkably stable. However, we could also observe singular events that gave unique insights into the network's structure. We discuss what we know and what we do not know about the actual Bitcoin network and the corresponding quality of Bitcoin network models. Furthermore, we examine how to prove Lightning secure by formally modeling payment channels, assess the compatibility of corresponding first and second layer models, and close with some future research directions

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Sarah Meiklejohn

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Bio

Sarah Meiklejohn is a Professor in Cryptography and Security at University College London and a Research Scientist at Google, where she works on security, transparency, and anti-abuse measures

Topic: De-Anonymization in Bitcoin

There are many heuristics that are used in practice to de-anonymize Bitcoin and other cryptocurrencies, but it is often hard to assess their effectiveness given a lack of ground-truth data. This talk presents an overview of these heuristics, as well as new research to both improve them and increase our confidence in their results

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