David Balbás
¡Hola! I am David Balbás, a PhD student in Cryptography at IMDEA Software Institute in Madrid (Spain) since October 2021. I am advised by Dario Fiore and co-advised by Maribel González-Vasco. In Autumn 2024, I was an intern at NTT Social Informatics Laboratories (Japan) hosted by Masayuki Abe. I was also an Applied Cryptography intern at Input-Output Global in the Summer of 2025.
I obtained a MSc in Computer Science at KTH Royal Institute of Technology (Sweden), and did my MSc Thesis at LASEC, EPFL (Switzerland). Before, I studied Mathematics and Physics at University of Cantabria (Spain) and worked as a Cryptography Engineer at BERTEN.
Interests
I work on the design and analysis of cryptographic primitives and protocols, as well as on their applications. More broadly, I am interested in theory and practice of cryptography, computer security and privacy.
My research is centered around the following topics. Don't hesitate to reach out if you are interested!
Publications
Preprints
- Circuit-Succinct Algebraic Batch Arguments from Standard Assumptions
David Balbás, Dario Fiore, Russell W. F. Lai
In submission - Critical Rounds in Multi-Round Proofs: Proof of Partial Knowledge, Trapdoor Commitments, and Advanced Signatures
Masayuki Abe, David Balbás, Dung Bui, Miyako Ohkubo, Zehua Shang, Akira Takahashi, Mehdi Tibouchi
In submission - Group Key Progression: Strong Security for Shared Persistent Data
Matilda Backendal, David Balbás, Miro Haller
In submission
Check out our talk at RWC 2025!
2024
- Fully-Succinct Multi-Key Homomorphic Signatures from Standard Assumptions
Gaspard Anthoine, David Balbás, Dario Fiore
CRYPTO 2024
2023
- Modular Sumcheck Proofs with Applications to Machine Learning and Image Processing
David Balbás, Dario Fiore, Maribel González Vasco, Damien Robissout, Claudio Soriente
ACM CCS 2023
Implementation, slides. - WhatsUpp with Sender Keys? Analysis, Improvements and Security Proofs
David Balbás, Daniel Collins, Phillip Gajland
ASIACRYPT 2023
Check out our poster @ USENIX Security 2023! - Chainable Functional Commitments for Unbounded-Depth Circuits
David Balbás, Dario Catalano, Dario Fiore, Russell W. F. Lai
TCC 2023 - Cryptographic Administration for Secure Group Messaging
David Balbás, Daniel Collins, Serge Vaudenay
USENIX Security 2023
2022
- Analysis and Improvements of the Sender Keys Protocol for Group Messaging
David Balbás, Daniel Collins, Phillip Gajland
RECSI 2022 - 2nd Best Paper Award!
Theses and Academic Projects
- On Secure Administrators for Group Messaging Protocols
MSc Thesis, 2021 - The Hardness of LWE and Ring-LWE: A Survey
Cryptology ePrint Archive, Report 2021/1358 - A Deep Learning approach for the detection of point sources in the Cosmic Microwave Background
BSc Thesis (Physics), 2019
Short conference paper @ ML4Astro 2022 - Attacks on RSA
BSc Thesis (Mathematics), 2019
Teaching and Service
- I am partially funded by an FPU Grant by "Ministerio de Universidades" of the Government of Spain.
- I have been a Teaching Assistant in the courses:
- Programming II, BSc in Mathematics and Computer Science, Universidad Politécnica de Madrid. 2023, 2024.
- Algorithms and Data Structures, BSc in Data Science, Universidad Politécnica de Madrid. 2023, 2024.
- Algorithms and Data Structures, BSc in Computer Science, Universidad Politécnica de Madrid. 2023.
- Computer Security, MSc in Computer Science, KTH Royal Institute of Technology. 2020.
- I am or have been part of the Program Committee for the conferences:
- I have reviewed scientific papers for the conferences:
- CRYPTO '22, '23, '24, '25
- EUROCRYPT '23, '24, '25, '26
- ACM CCS '24, '26
- ASIACRYPT '24, '25
- TCC '24, '25
- PKC '25, '26
Contact Me
- My email address is: david (dot) balbas (at) imdea.org
- LinkedIn profile
- My CV is available upon request.