Máté Horváth

PhD student

mhorvath (at) crysys.hu

web: www.crysys.hu/~mhorvath/
office: I.E. 429
tel: +36 1 463 2063

Current courses | Student projects | Publications

Short Bio

Máté obtained his MSc diploma in computer science in the Security and Privacy program of EIT ICT Labs at the University of Trento (Italy) and Eötvös Loránd University (Hungary). His bachelor degree is in mathematics from the Budapest University of Technology and Economics. He has been doing research in the CrySyS Lab. under the guidance of prof. Levente Buttyán since 2014.

Current Courses

IT Security Laboratory (VIHIMB01)

This laboratory extends and deepens the knowledge and skills obtained in the courses of the IT Security minor specialization by solving practical, hands-on exercises in real, or close-to-real environments.

Privacy-Preserving Technologies (VIHIAV35)

The sharing and explotation of the ever-growing data about individuals raise serious privacy concerns these days. Is it possible to derive (socially or individually) useful information about people from this Big Data without revealing personal information?
This course provides a detailed overview of data privacy. It focuses on different privacy problems of web tracking, data sharing, and machine learning, as well as their mitigation techniques. The aim is to give the essential (technical) background knowledge needed to identify and protect personal data. These skills are becoming a must of every data/software engineer and data protection officer dealing with personal and sensitive data, and are also required by the upcoming European General Data Protection Regulation (GDPR).

Publications

2017

Searchable Symmetric Encryption: Sequential Scan Can Be Practical

M. Horváth, I. Vajda

The 25th International Conference on Software, Telecommunications and Computer Networks (SoftCOM 2017), IEEE, 2017.

Bibtex | Abstract

@inproceedings {
   author = {Máté Horváth, István VAJDA},
   title = {Searchable Symmetric Encryption: Sequential Scan Can Be Practical},
   booktitle = {The 25th International Conference on Software, Telecommunications and Computer Networks (SoftCOM 2017)},
   publisher = {IEEE},
   year = {2017}
}

Keywords

Searchable Symmetric Encryption; Forward Index; Type-3 Pairings; MAC

Abstract

The proliferation of cloud computing highlights the importance of techniques that allow both securing sensitive data and flexible data management at the same time. One line of research with this double motivation is the study of Searchable Symmetric Encryption (SSE) that has provided several outstanding results in the recent years. These solutions allow sublinear keyword search in huge databases by using various data structures to store keywords and document identifiers. In this work, we focus on certain scenarios in which search over the whole database is not necessary and show that the otherwise inefficient sequential scan (in linear time) can be very practical. This is due to the fact that adding new entries to the database comes for free in this case while updating a complex data structure without information leakage is rather complicated. To demonstrate the practicality of our approach we build a simple SSE scheme based on bilinear pairings and prove its security against adaptive chosen-keyword attacks in the standard model under the widely used SXDH assumption.

2015

Attribute-Based Encryption Optimized for Cloud Computing

M. Horváth

SOFSEM 2015: Theory and Practice of Computer Science, Springer Berlin Heidelberg, 2015, Italiano, GiuseppeF. and Margaria-Steffen, Tiziana and Pokorny, Jaroslav and Quisquater, Jean-Jacques and Wattenhofer, Roger, pp. 566-577, http://dx.doi.org/10.1007/978-3-662-46078-8_47.

Bibtex | Abstract

@incollection {
   author = {Máté Horváth},
   title = {Attribute-Based Encryption Optimized for Cloud Computing},
   booktitle = {SOFSEM 2015: Theory and Practice of Computer Science},
   publisher = {Springer Berlin Heidelberg},
   year = {2015},
   editor = {Italiano, GiuseppeF. and Margaria-Steffen, Tiziana and Pokorny, Jaroslav and Quisquater, Jean-Jacques and Wattenhofer, Roger},
   pages = {566-577},
   note = {http://dx.doi.org/10.1007/978-3-662-46078-8_47}
}

Keywords

storage in clouds; access control; attribute-based encryption; multi-authority; user revocation

Abstract

In this work, we aim to make attribute-based encryption (ABE) more suitable for access control to data stored in the cloud. For this purpose, we concentrate on giving to the encryptor full control over the access rights, providing feasible key management even in case of multiple independent authorities, and enabling viable user revocation, which is essential in practice. Our main result is an extension of the decentralized CP-ABE scheme of Lewko and Waters [6] with identity-based user revocation. Our revocation system is made feasible by removing the computational burden of a revocation event from the cloud service provider, at the expense of some permanent, yet acceptable overhead of the encryption and decryption algorithms run by the users. Thus, the computation overhead is distributed over a potentially large number of users, instead of putting it on a single party (e.g., a proxy server), which would easily lead to a performance bottleneck. The formal security proof of our scheme is given in the generic bilinear group and random oracle models.

Attribute-Based Encryption Optimized for Cloud Computing

M. Horváth

Infocommunications Journal, vol. 7, no. 2, 2015, pp. 1-9.

Bibtex

@article {
   author = {Máté Horváth},
   title = {Attribute-Based Encryption Optimized for Cloud Computing},
   journal = {Infocommunications Journal},
   volume = {7},
   number = {2},
   year = {2015},
   pages = {1-9}
}

Keywords

storage in clouds; access control; attribute-based encryption; multi-authority; user revocation

Abstract