document

Trajectory Hiding and Sharing for Supply Chains with Differential Privacy

Li, T. (author), Xu, L. (author), Erkin, Z. (author), Lagendijk, R.L. (author)

With the fast development of e-commerce, there is a higher demand for timely delivery. Logistic companies want to send receivers a more accurate arrival prediction to improve customer satisfaction and lower customer retention costs. One approach is to share (near) real-time location data with recipients, but this also introduces privacy and...

conference paper 2024

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Practical Verifiable & Privacy-Preserving Double Auctions

Memar Zahedani, Armin (author), Vos, J.V. (author), Erkin, Z. (author)

Double auctions are procedures to trade commodities such as electricity or parts of the wireless spectrum at optimal prices. Buyers and sellers inform the auctioneer what quantity they want to buy or sell at specific prices. The auctioneer aggregates these offers into demand and supply curves and finds the intersection representing the...

conference paper 2023

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Verifiable Credentials with Privacy-Preserving Tamper-Evident Revocation Mechanism

Xu, Li (author), Li, T. (author), Erkin, Z. (author)

Verifiable Credential (VC) is a new standard proposed by the W3C association to facilitate the expression and verification of third-party-verified credentials on the Internet, such as passports or diplomas. However, the current VC data model lacks an explicit revocation design that guarantees the secure operations of the system, which limits its...

conference paper 2023

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Efficient Circuits for Permuting and Mapping Packed Values Across Leveled Homomorphic Ciphertexts

Vos, J.V. (author), Vos, D.A. (author), Erkin, Z. (author)

Cloud services are an essential part of our digital infrastructure as organizations outsource large amounts of data storage and computations. While organizations typically keep sensitive data in encrypted form at rest, they decrypt it when performing computations, leaving the cloud provider free to observe the data. Unfortunately, access to...

conference paper 2022

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Decentralized Private Freight Declaration & Tracking with Data Validation

Li, T. (author), Vos, J.V. (author), Erkin, Z. (author)

In January 2017, a truck crossed the border between Spain and France for the first time using an e-CMR: An electronic version of the primary transport document required for inter-European logistics. Since that crossing, researchers and logistic organizations have proposed a large number of ideas to further digitize Europe’s supply chain. Many of...

conference paper 2022

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PRIDE: A Privacy-Preserving Decentralised Key Management System

Kester, David (author), Li, T. (author), Erkin, Z. (author)

There is an increase in interest and necessity for an interoperable and efficient railway network across Europe, creating a key distribution problem between train and trackside entities’ key management centres (KMC). Train and trackside entities establish a secure session using symmetric keys (KMAC) loaded beforehand by their respective KMC...

conference paper 2022

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Multi-party private set intersection protocols for practical applications

Bay, Asli (author), Erkin, Z. (author), Alishahi, Mina (author), Vos, J.V. (author)

Multi-Party Private Set Intersection (MPSI) is an attractive topic in research since a practical MPSI protocol can be deployed in several real-world scenarios, including but not limited to finding the common list of customers among several companies or privacy-preserving analyses of data from different stakeholders. Several solutions have...

conference paper 2021

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Practical Exchange for Unique Digital Goods

Ersoy, O. (author), Genç, Ziya Alper (author), Erkin, Z. (author), Conti, M. (author)

Smart contracts can be used for the fair exchange of digital goods. A smart contract can escrow the exchange where the receiver deposits the payment, and the sender claims it by providing the goods. In the case of misbehavior, the parties provide proof on whether the received goods match the pre-agreed description or not. In general, the...

conference paper 2021

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Compare Before You Buy: Privacy-Preserving Selection of Threat Intelligence Providers

Vos, J.V. (author), Erkin, Z. (author), Dörr, C. (author)

In their pursuit to maximize their return on investment, cybercriminals will likely reuse as much as possible between their campaigns. Not only will the same phishing mail be sent to tens of thousands of targets, but reuse of the tools and infrastructure across attempts will lower their costs of doing business. This reuse, however, creates an...

conference paper 2021

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Privacy-Preserving Data Aggregation with Probabilistic Range Validation

Dekker, Florine W. (author), Erkin, Z. (author)

Privacy-preserving data aggregation protocols have been researched widely, but usually cannot guarantee correctness of the aggregate if users are malicious. These protocols can be extended with zero-knowledge proofs and commitments to work in the malicious model, but this incurs a significant computational cost on the end users, making adoption...

conference paper 2021

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Post-quantum adaptor signatures and payment channel networks

Esgin, Muhammed F. (author), Ersoy, O. (author), Erkin, Z. (author)

Adaptor signatures, also known as scriptless scripts, have recently become an important tool in addressing the scalability and interoperability issues of blockchain applications such as cryptocurrencies. An adaptor signature extends a digital signature in a way that a complete signature reveals a secret based on a cryptographic condition. It...

conference paper 2020

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PREDICT: Efficient Private Disease Susceptibility Testing in Direct-to-Consumer Model

Ugwuoke, C.I. (author), Erkin, Z. (author), Reinders, M.J.T. (author), Lagendijk, R.L. (author)

Genome sequencing has rapidly advanced in the last decade, making it easier for anyone to obtain digital genomes at low costs from companies such as Helix, MyHeritage, and 23andMe. Companies now offer their services in a direct-to-consumer (DTC) model without the intervention of a medical institution. Thereby, providing people with direct...

conference paper 2020

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How to profit from payments channels

Ersoy, O. (author), Roos, S. (author), Erkin, Z. (author)

Payment channel networks like Bitcoin’s Lightning network are an auspicious approach for realizing high transaction throughput and almost-instant confirmations in blockchain networks. However, the ability to successfully conduct payments in such networks relies on the willingness of participants to lock collateral in the network. In Lightning...

conference paper 2020

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VAPOR: A Value-Centric Blockchain that is Scale-out, Decentralized, and Flexible by Design

Ren, Z. (author), Erkin, Z. (author)

Blockchains is a special type of distributed systems that operates in unsafe networks. In most blockchains, all nodes should reach consensus on all state transitions with Byzantine fault tolerant algorithms, which creates bottlenecks in performance. In this paper, we propose a new type of blockchains, namely Value-Centric Blockchains (VCBs),...

conference paper 2019

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Privacy-Preserving Collection and Retrieval of Medical Wearables Data

Nateghizad, M. (author), Maulany, Christian (author), Erkin, Z. (author)

In recent years we have seen a rise in the amount of fitness tracking and self monitoring devices. These devices which often work in conjunction with a smartphone are becoming more accurate and are becoming widely adopted. This trend goes hand in hand with Electronic Health Care (e-health): the shift of health care to the digital domain. E...

conference paper 2017

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Privacy-Preserving Equality Test

Nateghizad, M. (author), Erkin, Z. (author), Lagendijk, R.L. (author)

Many countries around the globe are investing on e-healthcare increasingly, which offers tremendous benefits to all stakeholders in healthcare. Nevertheless, this technology introduces unprecedented privacy concerns toward patients and raise more uncertainty among them to use e-healthcare for monitoring their vital signs. These concerns...

conference paper 2017

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Mining encrypted software logs using alpha algorithm

Tillem, G. (author), Erkin, Z. (author), Lagendijk, R.L. (author)

The growing complexity of software with respect to technological advances encourages model-based analysis of software systems for validation and verification. Process mining is one recently investigated technique for such analysis which enables the discovery of process models from event logs collected during software execution. However, the...

conference paper 2017

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A decentralised energy trading architecture for future smart grid load balancing

Hijgenaar, S. (author), Erkin, Z. (author), Keviczky, T. (author), Siemons, Jos (author), Bisschops, Ralph (author), Verbraeck, A. (author)

Current state-of-the-art electric vehicle charging is found to have a profoundly disruptive effect on decentralised grids, increasing prevailing peak demand and causing network congestion. However, when charging behaviour is aligned with the needs of the grid, the batteries of electric vehicles can be used as a distributed resource to provide...

conference paper 2017

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Enhancing privacy of users in eID schemes

Shrishak, Kris (author), Erkin, Z. (author), Schaar, Remco (author)

In todays world transactions are increasingly being performed over the internetbut require identication of users as in face-to-face transactions. In order to facilitate eGovernance as well as other eCommerce services Electronic Identiation(eID) schemes, which intend to provide unique and reliable identication andauthentication of the users, have...

conference paper 2016

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Privacy-Preserving Alpha Algorithm for Software Analysis

Tillem, G. (author), Erkin, Z. (author), Lagendijk, R.L. (author)

Validation in a big software system can be managed by analysis of its behaviour through occasionally collected event logs. Process mining is a technique to perform software validation by discovering process models from event logs or by checking the conformance of the logs to a process model. A well-known algorithm in process mining to discover...

conference paper 2016