Charmaine Ndolo

AFT 2024 studionext-7

Hi, I am Charmaine (she/her) and I am currently working towards my PhD at the Technical University of Dresden advised by Florian Tschorsch.

blockchain networks security privacy resilience

I am a computer scientist (Master's from the Humboldt University in Berlin) with special interests in modern P2P systems. My main research interests are in the performance, security and resilience of blockchain-based P2P networks such as the Lightning network. My work tends to follow quantitative and empirical methods such as network measurements and simulations, while often applying methods from adjacent fields of computer science such as graph theory and game theory. During my Master's, I worked on some more theoretical aspects of distributed computing such as incentives and the analysis of open quorum systems (advised by Martin Florian). Prior to that, I worked on the analysis of complex graphs as a student assistant in the macsy group.

I am also an amateur baker and often spend my free time trying out new recipes. As of early 2024, I am a certified football referee in the Dresden football association and regularly officiate local games.

News

May 2026	Preprint of our paper “Security Analysis of Bitcoin’s V2 Transport Protocol: Exploiting Design Implications for Sustained Eclipse and Downgrade Attacks” is now available on arXiv.
Apr 2026	I will be serving on the program commitee for this year’s edition of the International Workshop on Cryptocurrencies and Blockchain Technology that will take place in Rome, Italy.
Apr 2026	Our paper “Network-level Side-channel Attacks in the Lightning Network” has been accepted to the ACM Transactions on Internet Technology journal.

Latest publication

TOIT
Network-level Side-channel Attacks in the Lightning Network

Charmaine Ndolo, and Florian Tschorsch

ACM Trans. Internet Technol., Apr 2026

Abs Bib
blockchain networks privacy security resilience

The Lightning network (LN) offers a solution to Bitcoin’s scalability limitations by providing fast and private off-chain payments. In addition to the LN’s long known application-level centralisation, recent work has highlighted its centralisation at the network level which makes it vulnerable to attacks on privacy by malicious actors. In this work, we explore the LN’s susceptibility to further attacks by a network-level actor such as a malicious autonomous system. We show that a network-level adversary can identify and interfere with all payments routed via their network by just examining the packet headers. Our results indicate that it is viable to accurately identify LN messages despite the fact that all inter-peer communication is end-to-end encrypted. While this can likely be used to achieve various adversarial objectives, we show how it can be exploited by an adversary to impose payment censorship and induce channel congestion. Additionally, we describe how a network-level observer can determine a node’s role in a payment path based on timing, direction of flow and message type, and demonstrate the approach’s feasibility using experiments in a live instance of the network. Simulations of the attack on a snapshot of the Lightning mainnet suggest that the impact of a congestion attack varies from mild to potentially dramatic depending on the adversary and type of payments that are censored. On the other hand, they show that the impact of a congestion attack, under the assumption that the adversary is not able to jam all channels, is less extreme. We analyse countermeasures the network can implement and come to the conclusion that an adequate solution involves constant message sizes as well as dummy traffic.
@article{ndolo2026network, author = {Ndolo, Charmaine and Tschorsch, Florian}, title = {Network-level Side-channel Attacks in the Lightning Network}, year = {2026}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, issn = {1533-5399}, url = {https://doi.org/10.1145/3810239}, doi = {10.1145/3810239}, journal = {ACM Trans. Internet Technol.}, month = apr, keywords = {blockchain, networks, privacy, security, resilience} }