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Alexandros Bakas: New protocols on encrypted data can help build user trust in cloud services

Tampere University
LocationKorkeakoulunkatu 1, Tampere
Room TB109 of the Tietotalo building, Hervanta campus, and remote connection
15.2.2024 10.00–14.00
LanguageEnglish
Entrance feeFree of charge
Photo: Naya Kalpakidou
In his doctoral dissertation MSc Alexandros Bakas explored and designed new cryptographic protocols for privacy-preserving data sharing and analytics through untrusted cloud environments. Such protocols allow users to directly operate on their encrypted data without the need to decrypt them first. This kind of research is of paramount importance in the contemporary era where personal data are often considered to be the “new oil”.

In his doctoral dissertation, Alexandros Bakas presents five publications which not only validate the importance of searching and performing operations on encrypted data but also provide innovative solutions to the identified challenges. They collectively underscore the transformative potential of advanced cryptographic protocols in enhancing data security and privacy, paving the way for a more secure digital future.

“In the modern digital era, the ability to search and perform operations on encrypted data has become increasingly crucial. This is largely due to the rapid expansion of data volumes, often described as the "new oil," coupled with escalating concerns over data privacy,” Bakas says.

As more data is stored in the cloud, robust security measures to safeguard this data from unauthorized access and misuse have become essential. A significant challenge in this area is conducting meaningful operations on data while it remains encrypted.

Trust is a key factor in the adoption and use of digital services

Traditional encryption methods offer high security but make the data impractical for any use beyond storage. This is where advanced cryptographic protocols like Symmetric Searchable Encryption (SSE), Functional Encryption (FE), Homomorphic Encryption (HE), and Hybrid Homomorphic Encryption (HHE) play a vital role.

“These protocols not only maintain data confidentiality but also enable computations on encrypted data, offering enhanced security and privacy”, Bakas says.

The ability to search and operate on encrypted data has numerous practical applications. For example, it allows for efficient Boolean queries on encrypted databases, crucial for many "big data" applications. It also enables phrase searches, vital for various machine learning applications, including intelligent medical data analytics. These capabilities are especially important for sensitive data, like health records or financial information, where user data privacy and security are paramount. Additionally, these capabilities can foster trust in digital systems. Trust is a key factor in the adoption and use of digital services. By ensuring data confidentiality, integrity, and availability, these protocols can help build user trust in cloud services. This trust can, in turn, drive broader adoption of digital services, leading to a more inclusive digital society.

Public defense on Thursday 15 February

The doctoral dissertation of MSc Alexandros Bakas in the field of Information Security titled Hidden in the Cloud: Advanced Cryptographic Techniques for Untrusted Cloud Environments will be publicly examined at the Faculty of Information Technology and Communication Sciences at Tampere University in room TB109 of the Tietotalo building (address: Korkeakoulunkatu 1, Tampere) at 12:00 on Thursday 15 February 2024.

The Opponent will be Assistant Professor Rafael Dowsley from the Monash University, Australia. The Custos will be Associate Professor Antonios Michalas from Tampere University, Finland.

The doctoral dissertation is available online The public defence can be followed via remote connection