Secure. Verifiable. Tamper-proof. A full-stack e-voting system combining biometric identity verification, blockchain transaction signing, and AI-powered document OCR — built to eliminate proxy voting and identity spoofing at scale.

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🧩 The Problem

Traditional online voting systems suffer from three critical flaws:

• Identity spoofing — anyone can impersonate a voter with just credentials
• Proxy voting — physical proxies are hard to detect digitally
• Lack of verifiability — voters can't confirm their vote was counted correctly

E-VoteChain solves all three with a multi-factor biometric pipeline backed by blockchain immutability.

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✅ Key Results

Metric	Result
🗳️ Voters supported	500+
🪪 Onboarding accuracy (Gemini OCR)	96%
🧬 Spoofing reduction (liveness detection)	85%
⚡ API response time improvement	40% faster
📈 System throughput	2.1× improvement

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📸 System in Action

Step 1 — Identity Verification Page (Empty State)

Voter lands on the verification page — uploads Aadhar/Government ID on the left and takes a live photo on the right

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Step 2 — Both Inputs Captured (Ready to Submit)

Document uploaded and live face captured — both green, status shows "Ready to Submit"

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Step 3 — Verification Successful

All checks pass — Gemini OCR extracts name, DOB, document type, and number. Liveness, Face Verification, and Database Storage all pass.

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Step 4 — Verification Details Breakdown

Full pipeline result: Document Processing ✅ · Liveness Detection ✅ · Face Matching ✅ (Facenet · Distance: 0.4499) · Data Storage ✅

🏗️ System Architecture

┌─────────────────────────────────────────────────────────────┐
│                    React Frontend (TypeScript)              │
│    Register → Upload ID → Face Scan → Vote → Confirmation   │
└────────────────────────┬────────────────────────────────────┘
                         │ REST API
┌────────────────────────▼───────────────────────────────────┐
│                     Flask Backend                          │
│                                                            │
│  ┌─────────────────┐   ┌──────────────────────────────┐    │
│  │  ML Identity    │   │   Blockchain Vote Layer      │    │
│  │  Pipeline       │   │                              │    │
│  │                 │   │  MetaMask Wallet Signing     │    │
│  │  1. Gemini OCR  │   │  On-chain vote submission    │    │
│  │  2. DeepFace    │   │  Immutable audit trail       │    │
│  │     Embedding   │   └──────────────────────────────┘    │
│  │  3. Liveness    │                                       │
│  │     Detection   │   ┌──────────────────────────────┐    │
│  │  4. Cosine Sim  │   │       PostgreSQL DB          │    │
│  │     Matching    │   │  Voter sessions & state      │    │
│  └─────────────────┘   └──────────────────────────────┘    │
└────────────────────────────────────────────────────────────┘

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🔐 ML Identity Verification Pipeline

The core of E-VoteChain is a 4-stage biometric verification pipeline that must pass before any vote is cast:

Stage 1 — Document OCR via Gemini API

• Voter uploads Aadhar card or Voter ID
• Gemini Vision API extracts: name, DOB, ID number, address
• Post-processing layer validates structure and handles low-res scans
• 96% extraction accuracy on real Indian government IDs

Stage 2 — Face Embedding via DeepFace

• Live webcam capture is passed through DeepFace to generate a 128-dim face embedding
• Same embedding is generated from the ID photo extracted during OCR

Stage 3 — Liveness Detection

• DeepFace liveness module detects whether the face is from a real person or a spoofed image/video
• Rejects printed photos, screen replays, and masked faces
• 85% reduction in spoofing attempts compared to baseline

Stage 4 — Dual-Stage Cosine Similarity Matching

• Computes cosine similarity between:
  • Live face embedding ↔ ID photo embedding
  • Live face embedding ↔ registered voter embedding (if pre-enrolled)
• Both thresholds must pass for verification to succeed

# Simplified matching logic
similarity = cosine_similarity(live_embedding, id_embedding)
if similarity >= THRESHOLD and liveness_score >= LIVENESS_THRESHOLD:
    grant_vote_access()
else:
    reject_with_reason()

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🗳️ Voting Flow

[1] Register          →  Voter submits Aadhar/Voter ID
[2] OCR Extraction    →  Gemini extracts identity fields
[3] Face Enrollment   →  DeepFace embeds and stores face vector
[4] Liveness Check    →  Live selfie verified as real person
[5] Face Match        →  Cosine similarity against registered embedding
[6] Wallet Connect    →  MetaMask wallet linked to verified identity
[7] Cast Vote         →  Vote signed and submitted on-chain
[8] Confirmation      →  Immutable receipt returned to voter

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🛠️ Tech Stack

Layer	Technology
Frontend	React 18, TypeScript, Tailwind CSS, Vite
Backend	Python, Flask, REST APIs
AI / OCR	Google Gemini API (Vision)
Biometrics	DeepFace (face recognition + liveness)
Database	PostgreSQL (voter sessions, verification state)
Blockchain	MetaMask (wallet signing + on-chain vote submission)
Deployment	Docker, Dockerfile

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📁 Repository Structure

Votechain_ML/
├── app.py                        # Flask entry point — API routes & orchestration
├── ml_logic/
│   ├── ocr.py                    # Gemini Vision OCR pipeline
│   ├── face_verification.py      # DeepFace embedding + liveness
│   ├── similarity.py             # Cosine similarity matching logic
│   └── utils.py                  # Preprocessing helpers
├── frontend/
│   ├── src/
│   │   ├── components/           # Registration, FaceScan, VotingUI
│   │   └── services/             # API client + MetaMask integration
│   └── package.json
├── uploads/                      # Temp storage for ID images (cleared post-verification)
├── index.html                    # Entry HTML
├── Dockerfile                    # Containerized deployment
├── requirements_final_cpu.txt    # Python dependencies (CPU-optimized)
└── README.md

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🚀 Getting Started

Prerequisites

• Python 3.10+
• Node.js 18+
• PostgreSQL running locally or via Docker
• Google Gemini API key
• MetaMask browser extension

Option A — Local Setup

# 1. Clone the repo
git clone https://github.com/E-VoteChain/Votechain_ML.git
cd Votechain_ML

# 2. Backend setup
python -m venv venv
source venv/bin/activate          # Windows: venv\Scripts\activate
pip install -r requirements_final_cpu.txt

# 3. Configure environment
cp .env.example .env
# Set: GEMINI_API_KEY, DATABASE_URL, SECRET_KEY

# 4. Run Flask backend
python app.py

# 5. Frontend setup (new terminal)
cd frontend
npm install
npm run dev
# → http://localhost:5173

Option B — Docker

docker build -t votechain-ml .
docker run -p 5000:5000 \
  -e GEMINI_API_KEY=your_key \
  -e DATABASE_URL=your_db_url \
  votechain-ml

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🔒 Security Design

• No raw biometric data stored — only embeddings (vectors), never photos
• Liveness detection prevents replay attacks using static images or videos
• One vote per verified identity — enforced at DB level with unique voter session constraints
• MetaMask signing ensures votes are cryptographically tied to a wallet, not just a session
• Upload hygiene — ID images are processed and deleted immediately, never persisted

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🧠 Challenges & Solutions

Challenge	Solution
Low-res Indian ID scans breaking OCR	Fine-tuned Gemini prompts + post-processing validation layer
Face spoofing via printed photos	DeepFace liveness detection module
High API latency on verification chain	Modular async pipeline — each stage runs independently
Dual embedding mismatch at edge cases	Two-threshold system with tuned cosine similarity floor

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👥 Team

Built as part of the E-VoteChain initiative — a full-stack e-voting platform with biometric security for accessible, tamper-proof digital democracy.

Role	Contributor
Frontend & ML Pipeline & Backend	Ayush Gupta
Blockchain	E-VoteChain Team

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Built with a belief that secure digital voting is not just possible — it's necessary.