Iosif (Sifis) Lazanakis

Profile Picture

About Me

Hi, I am Iosif, but most people know me as Sifis.
I hold an Integrated Master's Diploma in Electrical and Computer Engineer from the University of Patras. My diploma thesis was on the topic of Privacy Preservation on Biometric User Authentication Systems, where I developed a system that uses Homomorphic Encryption to protect the user's fingerprint reference template.

My main interests are focused on Computer Science and Computer Engineering topics, with a preference in Cybersecurity and Software Engineering, though I am always eager to explore new areas and broaden my knowledge beyond these fields.

I am currently serving my mandatory military service in the Hellenic Army, and I expect to be discharged by mid-September 2025.

In my free time, I like to practice on my technical skills, read books, go hiking, ride my bike and watch movies. Currently, I have focused on improving my skills in Cybersecurity, by being active on the TryHackMe Cybersecurity Training Platform. My progress, as well as details for my profile, can be accessed by the badge below.

Moreover, I am building a Cybersecurity Home Lab on my PC, using Virtual Machines deployed on VMWare Workstation. The lab mostly simulates a real-world corporate network, with a security solution hosting Firewall, DHCP, DNS and Mail Relay Servers and subnets for the Internal Servers and Clients. All the securtiy solutions and services are running on Open Source Software, such as Shorewall, Postfix, Dovecot, ClamAV, SpamAssassin, bind9 and ISC DHCP Server.

Feel free to contact me through any of the communication channels below. I’d be happy to answer your questions or exchange ideas.

My Diploma Thesis Summary

In my diploma thesis, I developed a biometric authentication system that utilizes fingerprint recognition for user identity verification. To protect the stored biometric templates, I implemented Paillier's Cryptosystem, a partially homomorphic encryption scheme, ensuring robust security for sensitive data.

Key Contributions:

  • Key Generation: I generated a user-specific public/private key pair to enhance security during the authentication process.
  • Fingerprint Template Construction: The system employed three fingerprint samples to create a comprehensive reference template. I extracted minutiae points from each sample, calculated minutiae pairs, and filtered redundant pairs to ensure accuracy.
  • Binary Vector Representation: The selected minutiae pairs were converted into a binary format and hashed into a unified vector, which was then encrypted using the user’s public key to safeguard the biometric information.

Performance Evaluation:

I evaluated the system's performance using the "Neurotechnology CrossMatch DB" dataset, which contains 51 unique fingerprints, each with 8 associated samples (totaling 408 samples). For each fingerprint:

  • A reference template was constructed using the initial three samples.
  • These templates were then compared against the remaining five samples of the same fingerprint and the eight samples from the other 50 fingerprints.
  • This analysis resulted in 255 correct comparisons and 20,400 false comparisons.
Results:
  • I plotted Receiver Operating Characteristic (ROC) curves, achieving an Equal Error Rate (EER) of 16%. This EER was consistent for both encrypted and unencrypted templates.
  • The registration process took approximately 3.5 hours on a high-performance computing system, while the verification process was completed in just 2.3 seconds.

Security Aspects:

The security of the biometric authentication system is fundamentally reliant on the key length of the Paillier Cryptosystem. Utilizing a key length of 3072 bits, I provided 128 bits of entropy, making it computationally infeasible to reverse-engineer the encryption with current technology. The system's security is based on the Decisional Composite Residuosity Assumption, ensuring a robust defense against potential attacks.

If you want to learn more about my diploma thesis, click here

Certifications

To continuously expand my expertise in Computer Science and Engineering, I have pursued various certifications that enhance my skills and knowledge. These certifications reflect my commitment to professional growth and my dedication to making the most of my free time.Some of my certifications include:

(ISC)2 CC Certified in Cybersecurity

By earning the (ISC)2 CC Certified in Cybersecurity certificate, I gained a comprehensive understanding of cybersecurity principles and practices in five key domains:

  1. Security Principles
  2. Incident Response, Business Continuity and Disaster Recovery Concepts
  3. Access Control Concepts
  4. Network Security
  5. Security Operations
The earning of this certification marks the beginning of my journey in the field of Cybersecurity, equipping me with the foundational knowledge and skills necessary to pursue a career in this dynamic and critical domain.

TryHackMe Cybersecurity 101 Learning Path

I completed the Cybersecurity 101 Learning Path on TryHackMe, which provided me with a comprehensive understanding of cybersecurity fundamentals, on both offensive and defensive domains. The curriculum of the learning path included among others:

  • Microsoft Windows, Active Directory and Linux Fundamentals
  • Networking Concepts and Tools
  • Cryptography
  • Exploitation and Web Hacking
  • Offensive and Defensive Security Tools
This learning path equipped me with an understanding of the key concepts and tools used in the field of cybersecurity, as well as practical skills to apply them in real-world scenarios.

IBM Data Science Professional Certificate

By completing the IBM Data Science Specialization on Coursera, I gained a comprehensive understanding of data science concepts and techniques. This certification equipped me with the skills to analyze data, create visualizations, and develop machine learning models. Through hands-on projects, as well as a capstone project, I applied my knowledge to real-world scenarios, enhancing my problem-solving abilities and analytical skills.

Django 4 and Python Full-Stack Developer Masterclass

I completed the Django 4 and Python Full-Stack Developer Masterclass on Udemy, which provided me with a comprehensive understanding of Django and Python. This certification enabled me to develop full-stack web applications and create RESTful APIs.

Linux Unhatched

I completed the Linux Unhatched course, from Cisco's Networking Academy platform, which introduced me to the fundamentals of Linux. This certification equipped me with the skills to navigate the Linux command line, manage files and directories, and perform basic system administration tasks.

Linux Essentials

I completed the Linux Essentials course, from Cisco's Networking Academy platform, which provided me with a comprehensive understanding of Linux fundamentals. This certification enabled me to perform essential Linux tasks, such as managing users and groups, managing ownership and permissions, and configuring network services. Moreover, it equipped me with the skills to develop shell scripts to automize system administration tasks.