🛡️ SecureVote - Cryptographic Full-Stack Java Electronic Voting System

SecureVote is an enterprise-grade full-stack Java web application designed for secure, transparent, and tamper-proof electronic elections. The system utilizes an anonymous SHA-256 vote chain ledger (blockchain-inspired) to guarantee absolute vote secrecy, single-ballot enforcement per voter, verifiable digital receipts, real-time result analytics, and automated cryptographic audit verification.

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🌟 Key Features

🔒 1. SHA-256 Cryptographic Chain Ledger

• Immutable Block Sequence: Each cast vote is cryptographically linked to the previous vote block hash (previousHash -> voteHash), forming a tamper-proof chain.
• Salted Voter Anonymization: Voters produce a salted hash sha256(voterId + electionId + positionId + salt) to prevent double voting while ensuring candidate choices remain completely unlinked from voter identities.
• Verifiable Digital Receipts: Voters receive a unique receipt code (e.g., VOTE-REC-D46D519D-9389) to publicly verify that their vote block exists in the ledger without exposing their ballot choices.

🔬 2. Auditor & Security Oversight Center

• Block-by-Block Audit Engine: Scans every ledger block to verify cryptographic parent links and payload hashes.
• Tamper Detection: If database records are illegally altered, the Auditor Portal immediately flags the broken block index and alerts security personnel.
• System Activity Logs: Logs system-wide actions with timestamps, actor IDs, actions, and IP addresses.

🗳️ 3. Digital Voting Booth (Interactive Wizard)

• 4-Step Guided Voting:
  1. Voter Verification: Authorization & constituency check.
  2. Ballot Selection: Interactive candidate cards with party manifestos and photos.
  3. Review & Cryptographic Sign: Final selection review before ledger signing.
  4. Cryptographic Receipt Ticket: Printable digital receipt with block hash details.

📊 4. Real-Time Results Analytics

• Dynamic Chart.js Integration: Live visual bar charts showing vote shares per candidate.
• Metrics Panel: Instant updates for total votes cast, turnout percentage, and leading candidate indicators.
• Candidate Tally Table: Detailed percentage breakdown per office.

⚙️ 5. Multi-Role Management

• Voter: View elections, cast ballots in active elections, verify receipt codes.
• Administrator: Create elections, add positions/candidates, toggle election states (UPCOMING, ACTIVE, PAUSED, CLOSED).
• Auditor: Execute SHA-256 cryptographic chain audits and review security logs.

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🏗️ System Architecture

                          ┌──────────────────────────────────────┐
                          │    SecureVote Web Portal (Frontend)  │
                          │ HTML5 / Glassmorphism CSS / App.js   │
                          └──────────────────┬───────────────────┘
                                             │ REST API (JSON)
                          ┌──────────────────▼───────────────────┐
                          │       Spring Boot 3 Web Application  │
                          │ ┌──────────────────────────────────┐ │
                          │ │ Controllers (Auth, Election, Vote)│ │
                          │ ├──────────────────────────────────┤ │
                          │ │ Services (Crypto, Ledger, Audit) │ │
                          │ ├──────────────────────────────────┤ │
                          │ │ Repositories (Spring Data JPA)   │ │
                          │ └──────────────────────────────────┘ │
                          └──────────────────┬───────────────────┘
                                             │ H2 Persistence
                          ┌──────────────────▼───────────────────┐
                          │   H2 Embedded Database / Ledger DB   │
                          └──────────────────────────────────────┘

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💻 Tech Stack

• Backend: Java 21, Spring Boot 3.3.4, Spring Web, Spring Data JPA
• Database: H2 In-Memory Database (with H2 Web Console)
• Frontend: HTML5, Vanilla CSS3 (Custom Glassmorphism Design System), JavaScript (ES6+), Chart.js (CDN)
• Build Tool: Apache Maven

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📁 Project Structure

ElectronicVotingSystem/
├── pom.xml
├── README.md
└── src/
    ├── main/
    │   ├── java/com/evoting/app/
    │   │   ├── ElectronicVotingSystemApplication.java
    │   │   ├── controller/
    │   │   │   ├── AdminController.java
    │   │   │   ├── AuditController.java
    │   │   │   ├── AuthController.java
    │   │   │   ├── ElectionController.java
    │   │   │   └── VotingController.java
    │   │   ├── model/
    │   │   │   ├── AuditLog.java
    │   │   │   ├── Candidate.java
    │   │   │   ├── Election.java
    │   │   │   ├── Position.java
    │   │   │   ├── User.java
    │   │   │   └── VoteLedger.java
    │   │   ├── repository/
    │   │   │   ├── AuditLogRepository.java
    │   │   │   ├── CandidateRepository.java
    │   │   │   ├── ElectionRepository.java
    │   │   │   ├── PositionRepository.java
    │   │   │   ├── UserRepository.java
    │   │   │   └── VoteLedgerRepository.java
    │   │   └── service/
    │   │       ├── AuditService.java
    │   │       ├── AuthService.java
    │   │       ├── CryptoService.java
    │   │       ├── DataInitializer.java
    │   │       ├── ElectionService.java
    │   │       └── VotingService.java
    │   └── resources/
    │       ├── application.properties
    │       └── static/
    │           ├── css/
    │           │   └── styles.css
    │           ├── js/
    │           │   └── app.js
    │           └── index.html

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🚀 Getting Started

Prerequisites

• Java Development Kit (JDK 21 or higher)
• Apache Maven 3.8+

1. Clone & Build the Application

git clone https://github.com/NKumar-B/Electronic_voting_system.git
cd Electronic_voting_system

# Compile project using Maven
mvn clean compile

2. Run the Application

mvn spring-boot:run

Once started, access the Web Portal in your browser:

• Web Portal: http://localhost:8080
• H2 Database Console: http://localhost:8080/h2-console
  • JDBC URL: jdbc:h2:mem:evotingdb
  • Username: sa
  • Password: (leave blank)

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🔑 Pre-Loaded Seed Credentials

The application auto-seeds initial demo users, active elections, candidates, and initial cryptographic vote blocks on startup:

Role	Voter ID	Email	Password	Access Rights
Voter 1	VOTER-1001	alice@example.com	voter123	Digital Voting Booth, Receipt Verification
Voter 2	VOTER-1002	bob@example.com	voter123	Digital Voting Booth, Receipt Verification
Admin	VOTER-ADMIN-001	admin@securevote.gov	admin123	Create Elections, Manage Candidates, Toggle Status
Auditor	VOTER-AUDIT-001	auditor@securevote.gov	audit123	Run SHA-256 Chain Verification, Inspect Audit Logs

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📡 REST API Documentation

Authentication (/api/auth)

• POST /api/auth/login: Authenticate user session.
• POST /api/auth/register: Register new voter.
• GET /api/auth/users: List registered users.

Elections (/api/elections)

• GET /api/elections: Fetch all system elections.
• GET /api/elections/{id}/ballot: Fetch positions, candidates, and total votes cast for an election.
• POST /api/elections: Create new election (Admin).
• PUT /api/elections/{id}/status: Toggle election status (ACTIVE, CLOSED, PAUSED) (Admin).
• POST /api/elections/positions/{positionId}/candidates: Add candidate to position (Admin).

Voting (/api/vote)

• POST /api/vote/cast: Atomically record vote in SHA-256 chain ledger.
• GET /api/vote/check: Check if voter has cast ballot for position.
• GET /api/vote/verify-receipt/{receiptCode}: Verify receipt code in cryptographic chain.

Audit & Security (/api/audit)

• GET /api/audit/verify-chain: Trigger full SHA-256 block chain verification.
• GET /api/audit/logs: Retrieve system activity audit logs.

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🛡️ Security & Integrity Design

Block N-1: [Hash: 6f8c4e...] <───┐
                                  │ Parent Link
Block N:   [Prev: 6f8c4e... | Election: 1 | VoterHash: a3b... | Candidate: 2 | Timestamp]
           └──► Block Hash (SHA-256): a01f37...

1. Chain Integrity: Changing any field in a past block alters its voteHash, causing all subsequent blocks to fail verification.
2. Double-Voting Prevention: The existsByElectionIdAndPositionIdAndVoterHash check prevents duplicate votes without identifying the voter's candidate selection.
3. Concurrency Safety: VotingService.castVote() uses synchronized transactions to prevent race conditions during vote registration.

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📜 License

This project is open-source and available under the MIT License.