Professor

Promoted to Professor.

Associate Professor

Promoted to Associate Professor.

Assistant Professor

I co-lead the Network and Information Security group (NISEC). The group consists of PhD students, professors, and researchers who conduct research in areas spanning from the theoretical foundations of cryptography to the design and implementation of leading edge efficient and secure communication protocols. Apart from my research work at NISEC, as an assistant professor, I am actively involved in the teaching activities of the University. Finally, my role also includes student supervision and research projects coordination.

Security, Privacy & GDPR Consultant

Responsible for the security analysis of the main IT systems that were used in the National Documentation Center as well as on the offered public services. Furthermore, my work involved the design of policies and security and privacy-preserving protocols that would make the overall organization GDPR-compliant. Finally, I was tasked with improving the security of existing systems/applications by staging attacks and providing solutions for any discovered vulnerabilities.

Assistant Professor

As a lecturer (assistant professor) I am teaching both undergraduate and postgraduate courses related to cryptography, forensics, cyber security and network security. My role expands to student supervision and research group coordination. In parallel, I am an active member of the department's project development and research activities. In addition to that, I am leading the cyber security research group at the University of Westminster. As the head of the cyber security research group, I lead research projects focused on network security and cryptography. The group comprises PhD students, professors and researchers. We mainly focus on applied research in security and privacy of widely deployed communication networks.

Postdoctoral Researcher

Actively involved in the current national and European research projects in the Security Lab, where I combine research with student supervision and project management. Within one year of starting at SICS, I have successfully obtained funding for three EU projects. Currently, I conduct research in the field of Security & Privacy for People-Centric Sensing, Cloud Computing, Trusted Computing, e-Voting Systems and Secure & Privacy Preserving e-Health Systems.

Security Consultant

Responsible for implementing and managing an information encryption system for the specific needs of the Hellenic Army. My work involved designing a secure single sign on protocol which connects online services of different web applications used by the military personnel. Additionally, I was tasked with improving the security of existing systems/applications by staging attacks and providing solutions for any discovered vulnerabilities.

Senior Web Developer

I was the team manager for Web-Related Projects. More precisely, I was responsible for talking directly with the clients and the Management Department in order to understand the needs of each project. Moreover, I was distributing the work to developers based on the requirements of each project while at the same time I was responsible for evaluating each part of the deliverable as well as programming the most demanding parts of the projects.

Researcher

Conducting research in provable security. More precisely, my research focused on private and secure e-voting systems, reputation systems, privacy in decentralized environments, cloud computing and privacy preserving protocols in participatory sensing applications.

Software Engineer

Development of European Union research projects.

Software Engineer

Programming and development of lottery-related games in Europe, the USA and Australia.

Oops!... They Stole it Again: Attacks on Split Learning

Authors: Tanveer Khan and Antonis Michalas
Venue: Proceedings of the 18th ACM Workshop on Artificial Intelligence and Security (AISec), co-located with the 32nd ACM Conference on Computer and Communications Security (CCS).
Where: Taipei, Taiwan, October 17, 2025.
OA & Research Artifacts: PDF

The Sound of Reduction: Minimal Inputs, Maximal Coverage

Authors: Iaroslav Gridin, Antonis Michalas. and Alejandro Cabrera Aldaya
Venue: 24th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom'25).
Where: Guiyang, China, 14—17 November 2025.

A Privacy-Centric Approach: Scalable and Secure Federated Learning Enabled by Hybrid Homomorphic Encryption

Authors: Khoa Nguyen, Tanveer Khan, Hossein Abdinasibfar and Antonis Michalas.
Venue: Proceedings of the Workshop on Responsible Healthcare using Machine Learning (RHCML), co-located with theEuropean Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML PKDD'25).
Where: Porto, Portugal 15—19 September 2025.
OA & Research Artifacts: PDF, CODE

Split Happens: Combating Advanced Threats with Split Learning and Function Secret Sharing

Authors: Tanveer Khan, Mindaugas Budzys and Antonis Michalas
Venue: 13th IEEE Conference on Communications and Network Security (CNS).
Where: Avignon, France, September 8—11, 2025.
OA & Research Artifacts: PDF, CODE

Blind Brother: Attribute-Based Selective Video Encryption

Authors: Eugene Frimpong, Bin Liu, Camille Nuoskala and Antonis Michalas
Venue: 15th ACM Conference on Data and Application Security and Privacy (CODASPY'25).
Where: Pittsburgh, PA, USA, June 4—6, 2025.
OA & Research Artifacts: PDF

Rainbow Over Clouds: A Lightweight Pairing-free Multi-Replica Multi-Cloud Public Auditing Scheme

Authors: Reyhaneh Rabaninejad, Antonis Michalas and Salil Kanhere
Venue: 19th International Conference on Risks and Security of Internet and Systems (CRiSIS'24).
Where: Aix-en-Provence, France, 26—28 November 2024.

A Pervasive, Efficient and Private Future: Realizing Privacy-Preserving Machine Learning Through Hybrid Homomorphic Encryption

Authors: Khoa Nguyen, Mindaugas Budzys, Eugene Frimpong, Tanveer Khan and Antonis Michalas.
Venue: 22nd IEEE International Conference on Dependable, Autonomic and Secure Computing (DASC'24).
Where: Boracay Island, Malay, Philippines, 5—8 November 2024.
OA & Research Artifacts: PDF, CODE A, CODE B

SPADE: Digging into Selective and PArtial DEcryption using Functional Encryption

Authors: Camille Nuoskala, Hossein Abdinasibfar and Antonis Michalas.
Venue: 20th EAI International Conference on Security and Privacy in Communication Networks (SecureComm’24).
Where: Dubai, UAE, 28—30 October 2024.
OA & Research Artifacts: PDF, CODE

Point Intervention: Improving ACVP Test Vector Generation Through Human Assisted Fuzzing

Authors: Iaroslav Gridin and Antonis Michalas.
Venue: 26th International Conference on Information and Communications Security (ICICS'24).
Where: 26—28 August, 2024, Mytilene, Greece.
OA & Research Artifacts: PDF, CODE

Wildest Dreams: Reproducible Research in Privacy-Preserving Neural Network Training

Authors: Tanveer Khan, Mindaugas Budzys, Khoa Nguyen and Antonis Michalas.
Venue: 24th Privacy Enhancing Technologies Symposium (PoPETs'24).
Where: 15—20 July, 2024, Bristol, U.K.
OA & Research Artifacts: PDF

FE[r]Chain: Enforcing Fairness in Blockchain Data Exchanges Through Verifiable Functional Encryption

Authors: Camille Foucault, Reyhaneh Rabbaninejad, Tassos Dimitriou and Antonis Michalas.
Venue: 29th ACM Symposium on Access Control Models and Technologies (SACMAT).
Where: 15—17 May, 2024, San Antonio, Texas, USA.
OA & Research Artifacts: PDF

Make Split, not Hijack: Preventing Feature-Space Hijacking Attacks in Split Learning

Authors: Tanveer Khan, Mindaugas Budzys and Antonis Michalas.
Venue: 29th ACM Symposium on Access Control Models and Technologies (SACMAT).
Where: 15—17 May, 2024, San Antonio, Texas, USA.
OA & Research Artifacts: PDF, CODE

Need for Speed: Leveraging the Power of Functional Encryption for Resource-Constrained Devices

Authors: Eugene Frimpong, Alexandros Bakas, Camille Foucault and Antonis Michalas.
Venue: 9th International Conference on IoT, BigData and Security (IoTBDS’24).
Where: 28—30 April 2024, Angers, France.
OA & Research Artifacts: PDF, CODE

Trustworthiness of X Users: A One-Class Classification Approach

Authors: Tanveer Khan, Fahad Sohrab, Antonis Michalas and Moncef Gabbouj.
Venue: 38th International Conference on Advanced Information Networking and Applications (AINA-2024).
Where: 19—17 April, 2024, Kitakyushu, Japan.
OA & Research Artifacts: PDF, CODE, DATASET

GuardML: Efficient Privacy-Preserving Machine Learning Services Through Hybrid Homomorphic Encryption

Authors: Eugene Frimpong, Khoa Nguyen, Mindaugas Budzys, Tanveer Khan and Antonis Michalas.
Venue: 39th ACM/SIGAPP Symposium On Applied Computing (SAC'24).
Where: 8—12 April, 2024, Avila, Spain.
OA & Research Artifacts: PDF, CODE A, CODE B

A More Secure Split: Enhancing the Security of Privacy-Preserving Split Learning

Authors: Tanveer Khan, Khoa Nguyen and Antonis Michalas.
Venue: 28th Nordic Conference on Secure IT Systems (NordSec'23).
Where: 16—17 November 2023, Oslo, Norway.
OA & Research Artifacts: PDF, CODE

Learning in the Dark: Privacy-Preserving Machine Learning using Function Approximation

Authors: Tanveer Khan and Antonis Michalas.
Venue: 22nd IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom'23).
Where: 01—03 November 2023, Exeter, U.K.
OA & Research Artifacts: PDF, CODE

Split Without a Leak: Reducing Privacy Leakage in Split Learning

Authors: Khoa Nguyen, Tanveer Khan and Antonis Michalas.
Venue: 19th EAI International Conference on Security and Privacy in Communication Networks (SecureComm’23).
Where: Hong Kong SAR, Hong Kong, 19—21 October 2023.
OA & Research Artifacts: PDF, CODE

stoRNA: Stateless Transparent Proofs of Storage-time

Authors: Reyhaneh Rabbaninejad, Behzad Abdolmaleki, Giulio Malavolta, Antonis Michalas and Amir Nabi.
Venue: 28th European Symposium on Research in Computer Security (ESORICS'23).
Where: Hague, the Netherlands, September 25—29, 2023.
OA & Research Artifacts: PDF

Love or Hate? Share or Split? Privacy-Preserving Training Using Split Learning and Homomorphic Encryption

Authors: Tanveer Khan, Khoa Nguyen, Antonis Michalas and Alexandros Bakas.
Venue: 20th Annual International Conference on Privacy, Security & Trust (PST'23).
Where: Copenhagen, Denmark, August 21—23, 2023.
OA & Research Artifacts: PDF, CODE

PoRt: Non-Interactive Continuous Availability Proof of Replicated Storage

Authors: Reyhaneh Rabbaninejad, Bin Liu and Antonis Michalas.
Venue: 38th ACM/SIGAPP Symposium On Applied Computing (SAC'23).
Where: Tallinn, Estonia, March 27—April 2, 2023.
OA & Research Artifacts: PDF

A Secure Bandwidth-Efficient Treatment for Dropout-Resistant Time-Series Data Aggregation

Authors: Reyhaneh Rabbaninejad, Bin Liu and Antonis Michalas.
Venue: Workshop on Privacy Preserving Computation in Pervasive Computing (PrivaCom'23) in conjunction with IEEE International Conference on Pervasive Computing and Communications (PerCom 2023).
Where: 13—17 March, 2023, Atlanta, USA.
OA & Research Artifacts: PDF

Split Ways: Privacy-Preserving Training of Encrypted Data Using Split Learning

Authors: Tanveer Khan, Nguyen and Antonis Michalas.
Venue: Workshop on Health Data Management in the Era of AI (HeDAI'23) in conjunction with EDBT/ICDT 2023.
Where: 28—31 March, 2023, Ioannina, Greece.
OA & Research Artifacts: PDF

Cryptographic Role-Based Access Control, Reconsidered

Authors: Bin Liu, Antonis Michalas and Bogdan Warinschi.
Venue: 16th International Conference on Provable and Practical Security (ProvSec’22)
Where: 11—12 November 2022, Nanjing, China.
OA & Research Artifacts: PDF

MetaPriv: Acting in Favor of Privacy on Social Media Platforms

Authors: Robert Cantaragiu, Antonis Michalas, Eugene Frimpong and Alexandros Bakas.
Venue: 18th EAI International Conference on Security and Privacy in Communication Networks (SecureComm’22).
Where: 17—19 October 2022, Kansas City, United States.
OA & Research Artifacts: PDF, CODE

Symmetrical Disguise: Realizing Homomorphic Encryption Services from Symmetric Primitives

Authors: Alexandros Bakas, Eugene Frimpong and Antonis Michalas.
Venue: 18th EAI International Conference on Security and Privacy in Communication Networks (SecureComm’22).
Where: 17—19 October 2022, Kansas City, United States.
OA & Research Artifacts: PDF, CODE

Feel the Quantum Functioning: Instantiating Generic Multi-Input Functional Encryption from Learning with Errors

Authors: Alexandros Bakas, Antonis Michalas, Eugene Frimpong and Reyhaneh Rabbaninejad.
Venue: 36th Annual WG 11.3 Conference on Data and Applications Security and Privacy (DBSec’22).
Where: 18—20 July 2022, Newark, NJ, USA.
OA & Research Artifacts: PDF, CODE

Private Lives Matter: A Differential Private Functional Encryption Scheme

Authors: Alexandros Bakas, Antonis Michalas and Tassos Dimitriou.
Venue: 12th ACM Conference on Data and Application Security and Privacy (CODASPY'22).
Where: 24—26 April 2022, Baltimore-Washington DC Area, United States.
OA & Research Artifacts: PDF

Attestation Waves: Platform Trust via Remote Power Analysis

Authors: Ignacio M. Delgado-Lozano, Macarena C. Martínez-Rodríguez, Alexandros Bakas, Billy Brumley and Antonis Michalas.
Venue: 20th International Conference on Cryptology and Network Security (CANS’21), December 13–15, 2021
Where: 13—15 December 2021, Vienna, Austria.
OA & Research Artifacts: PDF

Nowhere to Leak: A Multi-Client Forward and Backward Private Symmetric Searchable Encryption Scheme

Authors: Alexandros Bakas and Antonis Michalas.
Venue: 35th Annual WG 11.3 Conference on Data and Applications Security and Privacy (DBSec’21).
Where: 19—20 July 2021, Calgary, Canada.
OA & Research Artifacts: PDF, CODE

Arrows in a Quiver: A Secure Certificateless Group Key Distribution Protocol for Drones

Authors: Eugene Frimpong, Reyhaneh Rabbaninejad and Antonis Michalas.
Venue: 26th Nordic Conference on Secure IT Systems (NordSec'21).
Where: 29—30 November 2021, Tampere University (Virtual Event).
OA & Research Artifacts: PDF, CODE

Blind Faith: Privacy-Preserving Machine Learning Using Function Approximation

Authors: Tanveer Khan, Alexandros Bakas and Antonis Michalas.
Venue: 26th IEEE International Conference on Communications (ISCC’21).
Where: 05—08 October 2021, Athens, Greece.
OA & Research Artifacts: PDF, CODE

(F)unctional Sifting: A Privacy-Preserving Reputation

Authors: Alexandros Bakas, Antonis Michalas, and Amjad Ullah
Venue: 25th Nordic Conference on Secure IT Systems (NordSec'20).
Where: 23—25 November 2020, Virtual Event.
OA & Research Artifacts: PDF

Multi-Input Functional Encryption: Efficient Applications from Symmetric Primitives

Authors: Alexandros Bakas and Antonis Michalas.
Venue: 19th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom'20).
Where: December 29, 2020—January 01, Guangzhou, China.
OA & Research Artifacts: PDF

Trust and Believe — Should We? Evaluating the Trustworthiness of Twitter Users

Authors: Tanveer Khan and Antonis Michalas.
Venue: 19th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom'20)
Where: December 29, 2020—January 01, Guangzhou, China.

Attribute-Based Symmetric Searchable Encryption

Authors: Hai-Van Dang, Amjad Ullah, Alexandros Bakas and Antonis Michalas.
Venue: 2nd Workshop on Cloud Security and Privacy (Cloud S&P) in Conjunction with the 18th International Conference on Applied Cryptography and Network Security (ACNS’20).
Where: 19—22 October 2020, Rome, Italy (Virtual Event).
OA & Research Artifacts: PDF, CODE

Power Range: Forward Private Multi-Client Symmetric Searchable Encryption with Range Queries

Authors: Alexandros Bakas and Antonis Michalas.
Venue: 25th IEEE International Conference on Communications (ISCC’20).
Where: 07—10 July 2020, Rennes, France (Virtual Event).
OA & Research Artifacts: PDF, Presentation

Do not tell me what I cannot do! (The constrained device shouted under the cover of the fog): Implementing Symmetric Searchable Encryption on Constrained Devices

Authors: Eugene Frimpong, Alexandros Bakas, Hai-Van Dang and Antonis Michalas.
Venue: 5th International Conference on IoT, BigData and Security (IoTBDS’20).
Where: 07—09 May 2020, Prague, Czech Republic (Virtual Event).
OA & Research Artifacts: PDF, CODE

IoT-CryptoDiet: Implementing a Lightweight Cryptographic Library based on ECDH and ECDSA for the Development of Secure and Privacy-Preserving Protocols in Contiki-NG

Authors: Eugene Frimpong and Antonis Michalas.
Venue: 5th International Conference on IoT, BigData and Security (IoTBDS’20).
Where: 07—09 May 2020, Prague, Czech Republic (Virtual Event).
OA & Research Artifacts: PDF, CODE

SeCon-NG: Implementing a Lightweight Cryptographic Library based on ECDH and ECDSA for the Development of Secure and Privacy-Preserving Protocols in Contiki-NG

Authors: Eugene Frimpong and Antonis Michalas.
Venue: 35th ACM/SIGAPP Symposium On Applied Computing (SAC'20).
Where: March 30—April 3, 2020, Brno, Czech Republic (Virtual Event).
OA & Research Artifacts: PDF

Charlie and the CryptoFactory: Towards Secure and Trusted Manufacturing Environments

Authors: Antonis Michalas and Tamas Kiss
Venue: 20th IEEE Mediterranean Electrotechnical Conference (MELECON’20).
Where: 16—18 July, 2020, Palermo, Italy (Virtual Event).

MicroSCOPE: Enabling Access Control in Searchable Encryption with the use of Attribute-based Encryption and SGX

Authors: Antonis Michalas, Alexandros Bakas, Hai-Van Dang and Alexandr Zalitko
Venue: 24th Nordic Conference on Secure IT Systems (NordSec’19).
Where: 18—20 November, 2019, Aalborg, Denmark.
OA & Research Artifacts: PDF

Access Control in Searchable Encryption with the use of Attribute-Based Encryption and SGX

Authors: Antonis Michalas, Alexandros Bakas, Hai-Van Dang and Alexandr Zalitko
Venue: 10th ACM Cloud Computing Security Workshop (CCSW) in Conjunction with ACM Conference on Computer and Communications Security (CCS’19).
Where: 11—15 November, 2019, London, U.K.
OA & Research Artifacts: PDF

Modern Family: A Revocable Hybrid Encryption Scheme Based on Attribute-Based Encryption, Symmetric Searchable Encryption and SGX

Authors: Alexandros Bakas and Antonis Michalas
Venue: 15th EAI International Conference on Security and Privacy in Communication Networks (SecureComm’19)..
Where: 23—25, October, 2019, Orlando, United States.
OA & Research Artifacts: PDF

The Lord of the Shares: Combining Attribute-Based Encryption and Searchable Encryption for Flexible Data Sharing

Author: Antonis Michalas
Venue: 34th ACM/SIGAPP Symposium On Applied Computing (SAC'19).
Where: 08—12, April, 2019, Limassol, Cyprus, 2019, .
OA & Research Artifacts: PDF

Red Alert: Break-Glass Protocol to Access Encrypted Medical Records in the Cloud

Authors: Marcela Tuler de Oliveira, Antonis Michalas, Adrien E. D. Groot, Henk A. Marquering and Silvia Olabarriaga
Venue: 19th IEEE International Conference on E-health Networking, Application & Services (Healthcom'19).
Where: 14—16, October, 2019, Bogota, Colombia.

Towards Secure Cloud Orchestration for Multi-Cloud Deployments

Authors: Nicolae Paladi, Antonis Michalas and Hai-Van Dang.
Venue: 5th Workshop on CrossCloud Infrastructures & Platforms (CrossCloud’18) in Conjunction with EuroSys 2018.
Where: 23—26, April, 2018, Porto, Portugal.
OA & Research Artifacts: PDF

MemTri: A Memory Forensics Triage Tool using Bayesian Network and Volatility

Authors: Antonis Michalas and Rohan Murray.
Venue: 9th ACM CCS International Workshop on Managing Insider Security Threats (MIST’17) in Conjunction with ACM CCS 2017.
Where: October 30—03 November, 2017, Dallas, USA.
OA & Research Artifacts: PDF

Keep Pies Away from Kids: A Raspberry Pi Attacking Tool

Authors: Antonis Michalas and Ryan Murray.
Venue: 1st ACM CCS International Workshop on Internet of Things Security and Privacy (IoT S&P’17) in Conjunction with ACM CCS 2017.
Where: October 30—03 November, 2017, Dallas, USA.
OA & Research Artifacts: PDF

HealthShare: Using Attribute-Based Encryption for Secure Data Sharing Between Multiple Clouds

Authors: Antonis Michalas and Noam Weingarten.
Venue: 30th IEEE International Symposium on Computer-Based Medical Systems (CBMS’17).
Where: October 22—24 June, 2017, Thessaloniki, Greece.
OA & Research Artifacts: PDF

LocLess: Do You Really Care Your Cloud Files Are?

Authors: Antonis Michalas and Kassaye Yitbarek Yigzaw.
Venue: 9th IEEE/ACM International Conference on Utility and Cloud Computing.
Where: 12—15 December, 2016, Luxembourg.
OA & Research Artifacts: PDF

Sharing in the Rain: Secure and Efficient Data Sharing for the Cloud

Authors: Antonis Michalas
Venue: 11th International Conference for Internet Technology and Secured Transactions (ICITST’16).
Where: 05—07 December, 2016, Barcelona, Spain.
OA & Research Artifacts: PDF

Authors: Antonis Michalas and Rafael Dowsley.
Venue: 9th IEEE/ACM International Conference on Utility and Cloud Computing.
Where: 07—10 December, 2015, Limassol, Cyprus.
OA & Research Artifacts: PDF

PaaSword: A Holistic Data Privacy and Security by Design Framework for Cloud Services

Authors: Y. Verginadis, Antonis Michalas, P. Gouvas, G. Schiefer, G. Hubsch and I. Paraskakis
Venue: 5th International Conference on Cloud Computing and Services Science (CLOSER’15).
Where: 20—22 May, 2015, Lisbon, Portugal.
OA & Research Artifacts: PDF

Security Aspects of e-Health Systems Migration to the Cloud

Authors: Antonis Michalas, Nicolae Paladi and Christian Gehrmann
Venue: 16th IEEE International Conference on E-health Networking, Application & Services (Healthcom'14).
Where: 15—18 October, 2014, Natal, Brazil.
OA & Research Artifacts: PDF

Domain Based Storage Protection with Secure Access Control for the Cloud

Authors: Nicolae Paladi, Antonis Michalas and Christian Gehrmann
Venue: The 2014 International Workshop on Security in Cloud Computing, held in conjunction with the 9th ACM Symposium on Information, Computer and Communications Security (ASIACCS).
Where: 03—06 June, 2014, Kyoto, Japan.
OA & Research Artifacts: PDF

The Lord of the Sense: A Privacy Preserving Reputation System for Participatory Sensing Applications

Authors: Antonis Michalas, and Nikos Komninos
Venue: 19th IEEE International Conference on Communications (ISCC’2014).
Where: 23—26 June, 2014, Madeira, Portugal, 2014.
OA & Research Artifacts: PDF