Presentación de Retos
En esta sesión, varios miembros de nuestro equipo presentarán una serie de retos en distintos ámbitos de la criptografía y la seguridad. En la sesión de cierre del curso, prevista para junio, se premiarán las propuestas de solución más acertadas e innovadoras.
13:00 - 14:00 | Beyond Secrecy: Cryptography for Trust
Vanesa Daza (U. Pompeu Fabra)
For decades, we have viewed cryptography primarily as the discipline of hiding messages and protecting communications over insecure channels. Today, however, that picture is no longer sufficient. In this talk, I will show how the field has evolved far beyond that classical role: enabling open networks to coordinate without a central authority, allowing institutions to collaborate on sensitive data without revealing it, or even making it possible to verify the behavior of systems whose inner workings remain hidden. Contemporary cryptography is no longer just a technology of secrecy. It has become a foundational tool for building trust and providing formal guarantees in some of the most complex systems of our time.
14:00 - 15:00 | Divide and Secure: An Introduction to Secret Sharing
Oriol Farràs (U. Rovira i Virgili)
Consider the following problem: eleven scientists are working on a secret project and want to store their documents in a cabinet that can be opened if and only if at least six of them are present. How can this be achieved without trusting any single individual? 1979, Adi Shamir and George R. Blakley independently introduced a new family of schemes (now known as secret sharing schemes) that solved this kind of problems. Nearly fifty years later, these schemes have become fundamental tools in modern cryptography, underpinning areas such as distributed cryptography, secure multiparty computation, and digital signatures. In this talk, we will explore the core principles behind secret sharing schemes, present the main constuctions, and discuss some of their most important modern applications.
13:00 - 14:00 | Witness encryption based on signatures and its applications
Diego Castejón (IMDEA Software)
Blockchains are decentralized systems that enable monetary transactions without relying on ntermediaries
such as banks. Beyond simple payments, they support a range of financial applications, including digital
purchases, betting, asset exchange, and lending. Many of these applications are implemented using smart
contracts—programs executed on the blockchain—which inherently reveal their full logic on a public ledger.
This transparency can expose sensitive information and enable user profiling by adversaries.
As an alternative, financial applications can be realized through cryptographic protocols that rely on the
blockchain solely for transaction settlement, keeping the underlying logic private. In this talk, we focus
on a key primitive enabling such protocols: witness encryption based on signatures. Unlike traditional
public-key encryption, this primitive takes as encryption key a message and a public key, while decryption
requires a valid signature on the message and key used to encrypt.
14:00 - 15:00 | IoT security and privacy
Claudio Soriente (GMV)
The Internet of Things (IoT) may no longer dominate headlines as it did in the 2010s and early 2020s. Yet,
IoT remains deeply embedded in everyday life, with billions of deployed devices and continued growth
ahead.
In this talk, I will review a selection of influential papers on IoT security and privacy, alongside
real-world incidents that illustrate the field’s most persistent vulnerabilities. The goal is to highlight
the structural reasons why IoT systems so often fall short in security and privacy. I will also briefly
discuss the main countermeasures and research directions being pursued to reduce these risks.
When Local Isn’t Safe: Exploiting Localhost and the LAN for privacy abuse
Sesión ordinaria a cargo de Dr. Narseo Vallina-Rodríguez (IMDEA Networks).
Speaker Bio
I am an Associate Research Professor at IMDEA Networks where I lead the Internet Analytics Group (IAG). I am
also a co-founder of AppCensus, a US-based startup focused on the development of technologies for analysing
the privacy risks of mobile applications at scale. Before joining IMDEA, I was a research scientist at ICSI
at Berkeley (USA) and I obtained my Ph.D in Computer Science at the University of Cambridge under the
supervision of Prof.Jon Crowcroft. I also worked at industry research labs such as Vodafone R&D, T-labs
Berlin, and Telefonica Research in Barcelona.
My research advances the scientific foundations of security and privacy in modern digital ecosystems. I
combine large-scale measurement, empirical security research, and systems/program analysis to understand how
platform architectures, protocols, and third-party software enable pervasive tracking, covert data flows,
and structural privacy abuse. A core goal of my work is to bridge technical evidence with regulatory and
accountability perspectives, producing methods and datasets that help platforms, policymakers, and users
reason about privacy and security risks at scale.
I received best paper awards at the 2020 IEEE Symposium on Security and Privacy (S&P), USENIX Security’19,
ACM IMC’18, ACM HotMiddlebox’15, and ACM CoNEXT’14. For my research contributions, I have been selected as
ACM Senior Member in 2021 and I received the medal to “Young Investigators” awarded by the Royal Academy of
Engineering of Spain in 2023.
The societal value of my research contributions has been recognized also by European Data Protection
Agencies and key industry players. My work has influenced policy changes and triggered security improvements
in the Android platform, major browsers, and the Linux kernel, including the localhost permission introduced
in Android 17 and the local network permission introduced in Android 16. I am also selected as a SPE Expert
by the European Data Protection Board (EDPB) and have participated as expert in regulatory actions and
litigation.
In 2020, I have been selected as a Ramón y Cajal Senior Research Fellow by the Spanish Ministry of Science.
I also received multiple distinctions such as the AEPD Emilio Aced Award (2019, 2020 and 2021), the
CNIL-INRIA Privacy Protection Award (2019 and 2021), the Caspar Bowden PETS Award (2020), and the IETF/IRTF
Applied Networking Research Award. Additionally, I am the recipient of industry grants such as the 2018
Google Faculty Research Awards, DataTransparencyLab Grant in 2016, and Qualcomm’s Innovation Fellowship in
2012. International media outlets like The Washington Post, The Markup, The New York Times, The Guardian,
Financial Times, Wired, ArsTechnica, NPR, and El Pais have covered my research findings.
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Maria Naya Plasencia
(Inria)
Sesión de Clausura
13:00 - 14:00 The Journey of Differential Meet-in-the-Middle Attacks (so far)
In this talk, we will start discussing the importance of symmetric cryptanalysis, and some of its main open problems. Next, we will present differential MITM attacks, that were proposed in 2023, and provide the best know attacks on several families of primitives. We will discuss, from a high level point of view, this new type of cryptanalysis from its origins (meet-in-the-middle attacks), going through the rationale of different improvements (like biclique attacks), applications and comparison with other attacks.