Inspiration

Traditional biometric systems store raw facial images, creating high-risk attack surfaces in the event of a database breach. We aimed to design a zero-image storage authentication system. Password-based systems remain vulnerable to brute-force attacks, phishing, and credential leaks. We explored secure password-less authentication using biometric embeddings. With the rise of AI surveillance systems, we wanted to build a privacy-preserving alternative that encrypts biometric data at rest.

What it does

  1. Extracts 128-dimensional facial embeddings using a deep metric learning model (ResNet-based architecture from face_recognition).
  2. Encrypts embeddings using salted symmetric encryption (Fernet) before storing them in an SQLite database.
  3. Implements real-time liveness detection using facial landmark geometry (head orientation + blink detection via Eye Aspect Ratio).
  4. Three types of random liveness detection tests have been implemented.
  5. Performs identity verification using Euclidean distance in high-dimensional embedding space.

How we built it

Captured live webcam frames using OpenCV and converted them into RGB format for embedding extraction. Represented each face as a vector:

                                                                               𝐸 ∈ 𝑅^128

Implemented similarity matching using Euclidean distance:

                                                     $$d = \sqrt{\sum_{i=1}^{128}(x_i - y_i)^2}$$

Applied threshold-based decision logic for authentication. Secured stored embeddings using: 1. Salt concatenation 2. Fernet symmetric encryption 3. Local key-based decryption during verification Built an interactive dashboard using Streamlit for enrollment and authentication workflows.

Challenges we ran into

  1. Threshold calibration: Determining an optimal similarity threshold to minimize False Acceptance Rate (FAR) and False Rejection Rate (FRR).
  2. Process synchronization: Handling subprocess stdout/stderr communication between authentication scripts and the Streamlit UI.
  3. Environmental variance: Managing embedding fluctuations caused by lighting changes, camera noise, and slight facial pose variations.
  4. Liveness robustness: Ensuring blink detection and head movement verification were not falsely triggered.

Accomplishments that we're proud of

  1. We have successfully implemented a system for encrypted biometric storage without saving raw facial images to prevent data breaches to a good extent.
  2. Integrated computer vision, cryptography, database handling, and UI into a unified and working system.
  3. Developed a working anti-spoofing mechanism that combines geometric landmark analysis with dynamic challenges.
  4. Built a scalable prototype demonstrating secure password-less authentication.

What we learned

  1. We gained hands-on experience while working with high-dimensional face embeddings and understanding how similarity matching actually works in real-world biometric systems.
  2. Learned how facial landmark geometry can be used to detect blinks and head movement for real-time liveness verification.
  3. Understood why encryption, salting, and secure key management are critical when dealing with sensitive biometric data.
  4. Explored the balance between security and usability while tuning similarity thresholds to avoid false rejections and false acceptances.
  5. Debugged real-time AI workflows involving webcam input, subprocess handling, and integration between backend logic and the Streamlit interface.

What's next for LiveLock: Privacy-First Biometric Vault

Replace Euclidean distance with cosine similarity:

                                                                   similarity=(π‘₯⋅𝑦)/βˆ₯π‘₯βˆ₯βˆ₯𝑦βˆ₯

​ Implement deep learning–based anti-spoofing models (CNN-based presentation attack detection). Deploy as a containerized web service with secure key management. Introduce multi-factor authentication and adaptive threshold tuning. Optimize for edge-device performance and real-time latency reduction.

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