Ania M. Piotrowska's research while affiliated with WWF United Kingdom and other places

Publications (15)

Chapter
Payment channel networks, and the Lightning Network in particular, seem to offer a solution to the lack of scalability and privacy offered by Bitcoin and other blockchain-based cryptocurrencies. Previous research has focused on the scalability, availability, and crypto-economics of the Lightning Network, but relatively little attention has been pai...
Preprint
In this work, we present a discrete event mix network simulator, which allows analysing how anonymity, latency, and bandwidth overhead are affected by various scenarios of deployment and design choices. These design choices include network topology, mixing technique, volume of traffic, latency requirements, packet size or use of cover traffic. To t...
Conference Paper
Every modern online application relies on the network layer to transfer information, which exposes the metadata associated with digital communication. These distinctive characteristics encapsulate equally meaningful information as the content of the communication itself and allow eavesdroppers to uniquely identify users and their activities. Hence,...
Preprint
Payment channel networks, and the Lightning Network in particular, seem to offer a solution to the lack of scalability and privacy offered by Bitcoin and other blockchain-based cryptocurrencies. Previous research has already focused on the scalability, availability, and crypto-economics of the Lightning Network, but relatively little attention has...
Conference Paper
Full-text available
Mix networks are a key technology to achieve network anonymity and private messaging, voting and database lookups. However, simple mix network designs are vulnerable to malicious mixes, which may drop or delay packets to facilitate traffic analysis attacks. Mix networks with prov-able robustness address this drawback through complex and expensive p...
Preprint
Although Bitcoin in its original whitepaper stated that it offers anonymous transactions, de-anonymization techniques have found otherwise. Therefore, alternative cryptocurrencies, like Dash, Monero, and Zcash, were developed to provide better privacy. As Edward Snowden stated, "Zcash's privacy tech makes it the most interesting Bitcoin alternative...
Preprint
Full-text available
Mix networks are a key technology to achieve network anonymity, private messaging, voting and database lookups. However, simple mix networks are vulnerable to malicious mixes, which may drop or delay packets to facilitate traffic analysis attacks. Mix networks with provable robustness address this drawback through complex and expensive proofs of co...
Conference Paper
Full-text available
AnNotify is a scalable service for private, timely and low-cost on-line notifications, based on anonymous communication, sharding, dummy queries, and Bloom filters. We present the design and analysis of AnNotify, as well as an evaluation of its costs. We outline the design of AnNotify and calculate the concrete advantage of an adversary observing m...
Article
In this paper we present a light-weight data aggregation protocol based on probabilistic data structure used for representing a subset of elements called Bloom filter. Our construction is optimal (up to a small multiplicative constant) in terms of the size of the aggregated data representation. Moreover, all necessary operations have minimal comput...
Conference Paper
Full-text available
We present Loopix, a low-latency anonymous communication system that provides bi-directional 'third-party' sender and receiver anonymity and unobservability. Loopix leverages cover traffic and brief message delays to provide anonymity and achieve traffic analysis resistance, including against a global network adversary. Mixes and clients self-monit...
Article
Full-text available
We present Loopix, a low-latency anonymous communication system that provides bi-directional 'third-party' sender and receiver anonymity and unobservability. Loopix leverages cover traffic and brief message delays to provide anonymity and achieve traffic analysis resistance, including against a global network adversary. Mixes and clients self-monit...
Technical Report
Full-text available
AnoNotify is a service for private, timely and low-cost on-line notifications. We present the design and security arguments behind AnoNotify, as well as an evaluation of its cost. AnoNotify is based on mix-networks, Bloom filters and shards. We present a security definition and security proofs for AnoNotify. We then discuss a number of applications...
Conference Paper
One of the emerging problems on the border of privacy protection research and e-commerce is the monetization of sensitive data. More precisely, a client would like to obtain some statistical data about users’ personal information in exchange for a reward. To satisfy both parties, a monetization protocol should ensure that users’ privacy is not viol...

Citations

... 1. Node classification: It can be very useful to know the frequency and distribu- 35 tion of the different clients in an off-chain network. Such knowledge can also be relevant for security considerations, e.g., when planning the deployment of security patches. ...
... However, some pitfalls are introduced by the reputation system and the actual deployment is still a complex problem. Leibowitz et al. propose Miranda [39], another reputation-based design that detects and isolates active malicious mixes. They also discuss how to construct the cascade mixnet based on their faulty mixes detection scheme and a set of cascades are selected randomly for the upcoming epoch. ...
... In contrast to previous systems, Loopix [28] does not rely on synchronized rounds. Instead, users send packets according to a Poisson process, injecting dummy packets if no real message is available. ...
... This work was published in Proceedings of the 2017 on Workshop on Privacy in the Electronic Society (WPES) [53] and it is a joined work with George Danezis, Nethanel Gelernter, Jamie Hayes and Amir Herzberg. I have provided most of the key design ideas and security analysis. ...
... existing contributions. [12], [13], [16] ∈ B1; [17] ∈ B2; [15], [18] ∈ B3; [14] ∈ B4; [19] ∈ A1; [20], [21] ∈ A2; [22] ∈ A3; [23] ∈ A4; [24], [25] ∈ A5; [10], [6], [7], [26] ∈ A7. ...
... We explain how to do so in Appendix A.2. We also assume that users can use an anonymous communication channel [35,66] to communicate with the TS and SPs to protect their privacy at the network layer. Suppose that Alice uses Schnorr's identification protocol to authenticate herself to her bank. ...
... According to Piotrowska and Klonowski (2015), the privacy of individuals and data sensitivity should be considered in processing and collecting data. In general, one of the major challenges in data monetization is related to organizations, especially with respect to their credibility and public trust, concerning the issue of privacy (Thomas and Leiponen 2016). ...