Thomas Prantl - Chair of Computer Science II

Dr. rer. nat. Thomas Prantl

Chair of Software Engineering (Informatik II)
Department of Computer Science University of Würzburg
Am Hubland, 97074 Würzburg
Informatikgebäude, 1.OG, Room A118
Email: thomas.prantl@uni-wuerzburg.de

Research Interests

Privacy-preserving computing (homomorphic encryption, secure multi-party computation, ...)
Secure IoT communication (attribute-based and secure group encryption schemes, ...)
Secure training and deployment of artificial intelligence (poisoning attacks, watermarking, ...)

Selected Publications:

SoK: Poisoning Attacks and Defenses in Federated and Privacy-Preserving Machine Learning. Prantl, Thomas; Kulle, Edda; Horn, Lukas; Engel, Simon; Kounev, Samuel; in Proceedings on Privacy Enhancing Technologies (2027). 2027
- [ BibTeX ]
- [ EndNote ]
@article{Sardine_2027_Pets_Poison_SoK, author = {Prantl, Thomas and Kulle, Edda and Horn, Lukas and Engel, Simon and Kounev, Samuel}, journal = {Proceedings on Privacy Enhancing Technologies}, keywords = {t_journalmagazine}, month = {07}, note = {To appear.}, publisher = {Privacy Enhancing Technologies Symposium Advisory Board}, title = {SoK: Poisoning Attacks and Defenses in Federated and Privacy-Preserving Machine Learning}, volume = 2027, year = 2027 }

%0 Journal Article %1 Sardine_2027_Pets_Poison_SoK %A Prantl, Thomas %A Kulle, Edda %A Horn, Lukas %A Engel, Simon %A Kounev, Samuel %D 2027 %I Privacy Enhancing Technologies Symposium Advisory Board %J Proceedings on Privacy Enhancing Technologies %T SoK: Poisoning Attacks and Defenses in Federated and Privacy-Preserving Machine Learning %V 2027
Quo Vadis CKKS: Comparison of the Realization of Basic Mathematical Functions for the Homomorphic Cryptosystem CKKS using De Bello and Polynomial Approximations. Prantl, Thomas; Horn, Lukas; Engel, Simon; Bauer, André; Kounev, Samuel; in Journal of Information Security and Applications (2025). 93
- [ BibTeX ]
- [ EndNote ]
- [ URL ]
- [ DOI ]
@article{HE_Sardinen_2025, author = {Prantl, Thomas and Horn, Lukas and Engel, Simon and Bauer, André and Kounev, Samuel}, journal = {Journal of Information Security and Applications}, keywords = {t_journalmagazine}, month = {09}, note = {Published online June 2025}, publisher = {Elsevier}, title = {Quo Vadis CKKS: Comparison of the Realization of Basic Mathematical Functions for the Homomorphic Cryptosystem CKKS using De Bello and Polynomial Approximations}, volume = 93, year = 2025 }

%0 Journal Article %1 HE_Sardinen_2025 %A Prantl, Thomas %A Horn, Lukas %A Engel, Simon %A Bauer, André %A Kounev, Samuel %D 2025 %I Elsevier %J Journal of Information Security and Applications %R 10.1016/j.jisa.2025.104110 %T Quo Vadis CKKS: Comparison of the Realization of Basic Mathematical Functions for the Homomorphic Cryptosystem CKKS using De Bello and Polynomial Approximations %U https://www.sciencedirect.com/science/article/pii/S2214212625001474 %V 93
Security Analysis of a Decentralized, Revocable and Verifiable Attribute-Based Encryption Scheme. Prantl, Thomas; Lauer, Marco; Horn, Lukas; Engel, Simon; Dingel, David; Kounev, Samuel; Bauer, André; Krupitzer, Christian; Kounev, Samuel; in Proceedings of the 19th International Conference on Availability, Reliability and Security (2024). 1–11.
- [ BibTeX ]
- [ EndNote ]
- [ DOI ]
@inproceedings{ARES_2024_ABE, author = {Prantl, Thomas and Lauer, Marco and Horn, Lukas and Engel, Simon and Dingel, David and Kounev, Samuel and Bauer, André and Krupitzer, Christian and Kounev, Samuel}, booktitle = {Proceedings of the 19th International Conference on Availability, Reliability and Security}, keywords = {prantl_spezial}, month = {07}, pages = {1-11}, publisher = {ACM}, series = {ARES 2024}, title = {Security Analysis of a Decentralized, Revocable and Verifiable Attribute-Based Encryption Scheme}, year = 2024 }

%0 Conference Paper %1 ARES_2024_ABE %A Prantl, Thomas %A Lauer, Marco %A Horn, Lukas %A Engel, Simon %A Dingel, David %A Kounev, Samuel %A Bauer, André %A Krupitzer, Christian %A Kounev, Samuel %B Proceedings of the 19th International Conference on Availability, Reliability and Security %D 2024 %I ACM %P 1-11 %R https://doi.org/10.1145/3664476.3664487 %T Security Analysis of a Decentralized, Revocable and Verifiable Attribute-Based Encryption Scheme
De Bello Homomorphico: Investigation of the extensibility of the OpenFHE library with basic mathematical functions by means of common approaches using the example of the CKKS cryptosystem. Prantl, Thomas; Horn, Lukas; Engel, Simon; Iffländer, Lukas; Beierlieb, Lukas; Krupitzer, Christian; Bauer, André; Sakarvadia, Mansi; Foster, Ian; Kounev, Samuel; in International Journal of Information Security (2024). 23(2) 1149–1169.
- [ BibTeX ]
- [ EndNote ]
- [ DOI ]
@article{PrHoEnIfBeKrBaSaFoKo_IJoIS_SGC_Pareto, author = {Prantl, Thomas and Horn, Lukas and Engel, Simon and Iffl\"ander, Lukas and Beierlieb, Lukas and Krupitzer, Christian and Bauer, Andr\'e and Sakarvadia, Mansi and Foster, Ian and Kounev, Samuel}, journal = {International Journal of Information Security}, keywords = {t_journalmagazine}, month = {04}, note = {Published online November 2023}, number = 2, pages = {1149–1169}, title = {De Bello Homomorphico: Investigation of the extensibility of the OpenFHE library with basic mathematical functions by means of common approaches using the example of the CKKS cryptosystem}, volume = 23, year = 2024 }

%0 Journal Article %1 PrHoEnIfBeKrBaSaFoKo_IJoIS_SGC_Pareto %A Prantl, Thomas %A Horn, Lukas %A Engel, Simon %A Iffländer, Lukas %A Beierlieb, Lukas %A Krupitzer, Christian %A Bauer, André %A Sakarvadia, Mansi %A Foster, Ian %A Kounev, Samuel %D 2024 %J International Journal of Information Security %N 2 %P 1149--1169 %R 10.1007/s10207-023-00781-0 %T De Bello Homomorphico: Investigation of the extensibility of the OpenFHE library with basic mathematical functions by means of common approaches using the example of the CKKS cryptosystem %V 23
SCRAPS: Scalable Collective Remote Attestation for Pub-Sub IoT Networks with Untrusted Proxy Verifier Petzi, Lukas; Ben Yahya, Ala Eddine; Dmitrienko, Alexandra; Tsudik, Gene; Prantl, Thomas; Kounev, Samuel; (2022). (Bd. 31st USENIX Security Symposium (USENIX Security 22) USENIX Association.
- [ Abstract ]
- [ BibTeX ]
- [ EndNote ]
- [ URL ]
Remote Attestation (RA) is a basic security mechanism that detects malicious presence on various types of computing components, e.g., IoT devices. In a typical IoT setting, RA involves a trusted Verifier that sends a challenge to an untrusted remote Prover, which must in turn reply with a fresh and authentic evidence of being in a trustworthy state. However,most current RA schemes assume a central Verifier, which rep-resents a single point of failure. This feature is problematic when mutually suspicious stakeholders are involved. Furthermore, scalability issues arise as the number of IoT devices (Provers) grows. Although some RA schemes allow peer Provers to act as Verifiers, they involve unrealistic (for IoT devices) requirements, such as time synchronization and synchronous communication. Moreover, they incur heavy memory, computation,and communication burdens, while not considering sleeping or otherwise disconnected devices. Motivated by the need to address these limitations, we construct Scalable Collective Remote Attestation for Pub-Sub (SCRAPS), a novel collective RA scheme. It achieves scalability by outsourcing Verifier duties to a smart contract and mitigates DoS attacks against both Provers and Verifiers. It also removes the need for synchronous communication. Furthermore,RA evidence in SCRAPS is publicly verifiable, which significantly reduces the number of attestation evidence computations, thus lowering Prover burden. We report on a prototype of SCRAPS over Hyperledger Sawtooth (a blockchain geared for IoT use-cases) and evaluate its performance, scalability, and security aspects.

@proceedings{petzi2022scraps, abstract = {Remote Attestation (RA) is a basic security mechanism that detects malicious presence on various types of computing components, e.g., IoT devices. In a typical IoT setting, RA involves a trusted Verifier that sends a challenge to an untrusted remote Prover, which must in turn reply with a fresh and authentic evidence of being in a trustworthy state. However,most current RA schemes assume a central Verifier, which rep-resents a single point of failure. This feature is problematic when mutually suspicious stakeholders are involved. Furthermore, scalability issues arise as the number of IoT devices (Provers) grows. Although some RA schemes allow peer Provers to act as Verifiers, they involve unrealistic (for IoT devices) requirements, such as time synchronization and synchronous communication. Moreover, they incur heavy memory, computation,and communication burdens, while not considering sleeping or otherwise disconnected devices. Motivated by the need to address these limitations, we construct Scalable Collective Remote Attestation for Pub-Sub (SCRAPS), a novel collective RA scheme. It achieves scalability by outsourcing Verifier duties to a smart contract and mitigates DoS attacks against both Provers and Verifiers. It also removes the need for synchronous communication. Furthermore,RA evidence in SCRAPS is publicly verifiable, which significantly reduces the number of attestation evidence computations, thus lowering Prover burden. We report on a prototype of SCRAPS over Hyperledger Sawtooth (a blockchain geared for IoT use-cases) and evaluate its performance, scalability, and security aspects.}, author = {Petzi, Lukas and Ben Yahya, Ala Eddine and Dmitrienko, Alexandra and Tsudik, Gene and Prantl, Thomas and Kounev, Samuel}, keywords = {sss-group}, month = {08}, publisher = {USENIX Association}, title = {SCRAPS: Scalable Collective Remote Attestation for Pub-Sub IoT Networks with Untrusted Proxy Verifier}, volume = {31st USENIX Security Symposium (USENIX Security 22)}, year = 2022 }

%0 Conference Proceedings %1 petzi2022scraps %A Petzi, Lukas %A Ben Yahya, Ala Eddine %A Dmitrienko, Alexandra %A Tsudik, Gene %A Prantl, Thomas %A Kounev, Samuel %D 2022 %I USENIX Association %T SCRAPS: Scalable Collective Remote Attestation for Pub-Sub IoT Networks with Untrusted Proxy Verifier %U https://www.usenix.org/conference/usenixsecurity22/presentation/petzi %V 31st USENIX Security Symposium (USENIX Security 22) %X Remote Attestation (RA) is a basic security mechanism that detects malicious presence on various types of computing components, e.g., IoT devices. In a typical IoT setting, RA involves a trusted Verifier that sends a challenge to an untrusted remote Prover, which must in turn reply with a fresh and authentic evidence of being in a trustworthy state. However,most current RA schemes assume a central Verifier, which rep-resents a single point of failure. This feature is problematic when mutually suspicious stakeholders are involved. Furthermore, scalability issues arise as the number of IoT devices (Provers) grows. Although some RA schemes allow peer Provers to act as Verifiers, they involve unrealistic (for IoT devices) requirements, such as time synchronization and synchronous communication. Moreover, they incur heavy memory, computation,and communication burdens, while not considering sleeping or otherwise disconnected devices. Motivated by the need to address these limitations, we construct Scalable Collective Remote Attestation for Pub-Sub (SCRAPS), a novel collective RA scheme. It achieves scalability by outsourcing Verifier duties to a smart contract and mitigates DoS attacks against both Provers and Verifiers. It also removes the need for synchronous communication. Furthermore,RA evidence in SCRAPS is publicly verifiable, which significantly reduces the number of attestation evidence computations, thus lowering Prover burden. We report on a prototype of SCRAPS over Hyperledger Sawtooth (a blockchain geared for IoT use-cases) and evaluate its performance, scalability, and security aspects. %@ 978-1-939133-31-1

List of all publications: Thomas Prantl

Teaching & Supervision

Co-supervision of five PhD students
Design and delivery of the lecture "Introduction to Homomorphic Cryptosystems" at the Universities of Würzburg, Hohenheim, and Frankfurt
Lecture coordination for the course "Software Engineering"
Supervision of Bachelor's and Master's theses, software labs, and seminars

Conference and Workshop Organisation

2026: Symposium on Software Performance (SSP) - Organizer
2025: Intelligent Cybersecurity Conference (ICSC) - Technical Program Committee member
2024: Intelligent Cybersecurity Conference (ICSC) - Technical Program Committee member
2023: International Conference on Information Security Practice and Experience (ISPEC) - Session Chair
2022: ACM/SPEC International Conference on Performance Evaluation (ICPE) - Web Chair
2021: SPS Special Session on Cyber Resilience and Antifragility in Complex Distributed Systems (CyRA) - PC member
2020: Workshop on Self-Aware Computing (SEAC) - Publicity Chair

Selected Reviewer Activities

2026: Symposium on Software Performance (SSP), International Joint Conference on Neural Networks (IJCNN), Special Interest Group Computer Education (SIGCSE), Discover Computing, The Journal of Supercomputing
2025: International Symposium on the Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), International Conference on Performance Engineering (ICPE)
2024: Intelligent Cybersecurity Conference (ICSC), International Symposium on the Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), International Conference on Performance Engineering (ICPE)
2023: International Symposium on the Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), International Conference on Performance Engineering (ICPE)
2021: Symposium on Software Performance (SSP), International Workshop on Self-Protecting Systems (SPS), International Conference on Distributed Computing Systems (ICDCS), International Conference on Performance Engineering (ICPE), International Conference on Utility and Cloud Computing (UCC)
2020: International Symposium on the Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), International Conference on Performance Engineering (ICPE), Workshop on Artificial Intelligence for IT Operations (AIOPs), International Conference on Autonomic Computing and Self-Organizing Systems (ACSOS), Workshop on Self-Aware Computing (SeAC), International Symposium on Software Engineering for Adaptive and Self-Managing Systems (SEAMS)
2019: International Conference on Utility and Cloud Computing (UCC), International Symposium on the Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS), International Conference on Performance Engineering (ICPE), International Workshop on Practical Applications of Stochastic Modeling (PASM), Symposium on Software Performance (SSP), Computer Society Signature Conference on Computers, Software and Applications (COMSPAC), International Workshop on Self-Improving System Integration (SISSY), International Symposium on Software Engineering for Adaptive and Self-Managing Systems (SEAMS)

Degrees

Doktor der Naturwissenschaften in Informatik mit summa cum laude (Dr. rer. nat. in Computer Science with distinction)
Master Informatik (Master of Computer Science)
1. Staatsexamen für das Lehramt am Gymnasium (Physik/Informatik)
Bachelor Informatik (Bachelor of Computer Science)
Bachelor Naturwissenschaftliche Grundlagen (Bachelor of Natural Science Foundations)

List of all publications: Thomas Prantl

Bildnachweise