1. On the Ljunggren equation $y^2=2x^4-1$, Fibonacci Conference (Patra 2008)

2. Η μέθοδος του Chabauty και Ακέραια Σημεία επί Ελλειπτικών Καμπύλων (In Greek, Department of Mathematics, University of Ioannina; Ioannina, 18 Nov. 2008)

3. Μέθοδοι Αλγεβρικής Γεωμετρίας με έμφαση στις Διοφαντικές Εξισώσεις ( In Greek, National Technical University of Athens; Athens, 27 Jan. 2009)

4. Pell numbers of the form $px^2.$ (3rd Internatonal Conference in Algebraic Informatics, 19-22 May 2009, Thessalolniki.

5. Balanced Solutions of Linear Diophantine Equations, 7th Athens Colloquium on Algorithms and Complexity (ACAC12), 27-28 August, University of Athens, Athens.

6. Balanced Solutions of Linear Diophantine Equations, 2nd International Conference on Applications of Mathematics and Informatics in Military Sciences (AMIMS), 11-12 April 2013, Hellenic Military Academy, Athens.

7. Improved Knapsack Algorithms, 3rd International Conference on Cryptography, Cyber Security an Information Warfare (3rd CryCybIW), 26-27 May 2016, Hellenic Military Academy, Athens).

8. Improved Knapsack Algorithms, 11th Athens Colloquium on Algorithms and Complexity (ACAC 2016), Athens, Greece.

9a. Elliptic curves and Cryptography, 90 years of Mathematics in AUTH, 19 & 20 December 2018, Aristotle University of Thessaloniki, Thessaloniki.

9b. Elliptic curves and cryptography [paper], a summary of the previous talk.

10. Post Quantum Crypto, Invitation by ACM student chapter of AUTH, 20 May 2019

11. Enhancing an Attack to DSA Schemes, CAI 2019, Serbia.

12. Cybersecurity in quantum era, Sfhmmy 12, 23 April 2021, Thessaloniki.

13. Introduction to the terminology of Blockchain. OK!Thess & Europe Direct Thessalonikis (invitation), Thessaloniki,

14. Sagemath computer algebra system, 19/11/2022, Fosscomm 2022 (remote).

15. Why the current encryption standards must be updated? The case of Post Quantum Cryptography., Sfhmmy 14, April 2023, Volos.

16. Message recovery in NTRU based on CVP, NuTMiC 2024, June 24 – June 26, 2024, Szczecin, Poland.