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Friedhelm Victor

Friedhelm Victor
TRM Labs

Doctor of Philosophy

About

24
Publications
29,717
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920
Citations
Introduction

Publications

Publications (24)
Preprint
Full-text available
Privacy-focused cryptoassets like Monero are intentionally difficult to trace. Over the years, several traceability heuristics have been proposed, most of which have been rendered ineffective with subsequent protocol upgrades. Between 2019 and 2023, Monero wallet application bugs "Differ By One" and "10 Block Decoy Bug" have been observed and ident...
Article
Full-text available
Decentralized Finance (DeFi) is a new financial paradigm that leverages distributed ledger technologies to offer services such as lending, investing, or exchanging cryptoassets without relying on traditional centralized intermediaries. A range of DeFi protocols implements these services as a suite of smart contracts, i.e., software programs that en...
Chapter
The rapid growth of the Ethereum ecosystem since 2020 has been driven by the proliferation of several DeFi protocols [10], which are application-layer programs that provide Decentralized Finance (DeFi) services [14, 16] such as the exchange of cryptoassets on decentralized exchanges (DEXs) [2, 7, 15], their lending and borrowing [1, 4, 8], or the c...
Article
Full-text available
We present a measurement study on compositions of Decentralized Finance (DeFi) protocols, which aim to disrupt traditional finance and offer services on top of distributed ledgers, such as Ethereum. Understanding DeFi compositions is of great importance, as they may impact the development of ecosystem interoperability, are increasingly integrated w...
Preprint
Full-text available
We present the first study on compositions of Decentralized Finance (DeFi) protocols, which aim to disrupt traditional finance and offer financial services on top of the distributed ledgers, such as the Ethereum. Starting from a ground-truth of 23 DeFi protocols and 10,663,881 associated accounts, we study the interactions of DeFi protocols and ass...
Chapter
Bitcoin (BTC) pseudonyms (layer 1) can effectively be deanonymized using heuristic clustering techniques. However, while performing transactions off-chain (layer 2) in the Lightning Network (LN) seems to enhance privacy, a systematic analysis of the anonymity and privacy leakages due to the interaction between the two layers is missing. We present...
Preprint
Full-text available
Cryptoassets such as cryptocurrencies and tokens are increasingly traded on decentralized exchanges. The advantage for users is that the funds are not in custody of a centralized external entity. However, these exchanges are prone to manipulative behavior. In this paper, we illustrate how wash trading activity can be identified on two of the first...
Article
Full-text available
Over the past decade, blockchains and distributed ledger technologies have rapidly evolved. With increasing transaction volumes and the proliferation of decentralized applications based on smart contracts, a need for a deeper understanding arises. We structure the field that we term distributed ledger analytics.
Chapter
Full-text available
For many years, address clustering for the identification of entities has been the basis for a variety of graph-based investigations of the Bitcoin blockchain and its derivatives. Especially in the field of fraud detection it has proven to be useful. With the popularization and increasing use of alternative blockchains, the question arises how to r...
Preprint
Payment channel networks (PCNs) have emerged as a promising alternative to mitigate the scalability issues inherent to cryptocurrencies like Bitcoin and are often assumed to improve privacy, as payments are not stored on chain. However, a systematic analysis of possible deanonymization attacks is still missing. In this paper, we focus on the Bitcoi...
Conference Paper
Full-text available
In the past years, cryptocurrencies have received a lot of attention in popular media. Having attracted significant speculation, prices have soared in 2017, fell in 2018 and are generally known to be very volatile. However, some of the price changes have been due to organized manipulation. Traditionally known in the world of penny stocks and made i...
Chapter
Full-text available
The blockchain and cryptocurrency space has experienced tremendous growth in the past few years. Covered by popular media, the phenomenon of startups launching Initial Coin Offerings (ICOs) to raise funds led to hundreds of virtual tokens being distributed and traded on blockchains and exchanges. The trade of tokens among participants of the networ...
Article
Full-text available
Supply Chain Traceabiliy is one of the most promising use cases to benefit from blockchain characteristics such as decentralization, immutability and transparency, without requiring to build prior trust relationships among entities. A plethora of blockchain-based supply chain traceability solutions has been proposed recently. However, current syste...
Conference Paper
Full-text available
A decentralized ride- or carsharing application is among the early proposals of what smart contracts on blockchains may enable in the future. To facilitate use cases in the field of location-based services (LBS), smart contracts need to receive trustworthy positioning information, and be able to process them. We propose an approach on how geofences...
Preprint
Growing consumer awareness as well as manufacturers' internal quality requirements lead to novel demands on supply chain traceability. Existing centralized solutions suffer from isolated data storage and lacking trust when multiple parties are involved. Decentralized blockchain-based approaches attempt to overcome these shortcomings by creating dig...
Conference Paper
Full-text available
Growing consumer awareness as well as manufac-turers' internal quality requirements lead to novel demands on supply chain traceability. Existing centralized solutions suffer from isolated data storage and lacking trust when multiple parties are involved. Decentralized blockchain-based approaches attempt to overcome these shortcomings by creating di...
Conference Paper
Full-text available
Mobile traffic analysis is typically performed on large datasets, which are collected by telecommunication operators within their network. To protect the privacy of subscribers, data is often anonymized. Therefore it is challenging to conceive mobility models of subscribers, because ground truth is costly to acquire. In this paper we demonstrate ho...

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