“Joint Female Lecture” on July 15, 2021

Lecture by Prof. Dr. Stefanie Roos with award ceremony of the Female Student (Travel) Awards following


The RTG 2050 Female Scientists Lecture Series in cooperation with the Ruzena Bajcsy Lectures on Communications and Resilience by CRC MAKI and LOEWE center emergenCITY welcomes Prof. Dr. Stefanie Roos (TU Delft, Netherlands) with her speech on “Good Routing Protocols Should Be Like Ninjas: Untraceable and Fast”.

Thursday, July 15, 2021, 4:15 pm



Routing data anonymous is important whenever sender and

receiver should not be linked. Key examples here are a whistleblower and

a journalist or a victim of domestic violence and a police officer.

Furthermore, this unlinkability can be important for companies as well.

If a company starts manufacturing a new and still secret product, they

do not want their competitors to know which provider of raw material

they are paying as it might reveal information about their product.

Networks like Tor are very effective if parties can establish

(transport-layer) connections with any other party. However, there are

scenarios when opening connections is not possible or too costly. For

instance, parties might aim to hide their participation in the network

by only connecting to a few trusted parties. In the context of

blockchain, adding a new direct (off-chain) transaction partner can be

time-consuming and costly. Thus, there is a need to design novel

protocols that can deal with connectivity restrictions. In other words,

we need routing protocols that provide anonymity and efficiency for

application-layer networks that are route-restricted.

In this talk, I first show how dynamic network coordinates can be

assigned in such networks and how these coordinates facilitate efficient

routing. Afterwards, I show how the anonymity of these routing

protocols can be improved and discuss the limits on the provided

anonymity in comparison to Tor-like systems. Last, I specify how this

type of protocols can be used in two key applications:

membership-concealing overlay networks and payment channel networks. I

highlight the importance of payment channel networks for blockchain

scalability and hence the broad adoption of blockchain.


Stefanie Roos is an assistant professor for distributed systems at

TU Delft and the Delft Blockchain Lab. Her work deals with trade-offs

between privacy, security, and performance in decentralized systems. She

contributed to the censorship-resistant P2P network Freenet and designed

SpeedyMurmurs, a routing algorithm for payment channel networks like

Lightning. Her current research is focused on improving layer2 protocols

for blockchains as well as designing more efficient anonymity systems.

Before joining TU Delft, she was a post-doctoral researcher at

University of Waterloo, working with Prof. Ian Goldberg, and a PhD

scholar at TU Dresden and TU Darmstadt. Her PhD thesis, supervised by

Prof. Thorsten Strufe, won the KuVS award for the best PhD thesis in the

area of networks and distributed systems in Germany.