NoteVault — Password Protected Notes Application

Java Swing + SQLite + BCrypt + AES-256

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Project Overview

NoteVault is a secure desktop notes application that protects your data using:

• BCrypt for password hashing (work factor 12)
• AES-256-CBC with PBKDF2 key derivation for note encryption
• SQLite for persistent local storage
• Java Swing for the GUI

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Project Structure

src/
├── Main.java                     ← Entry point
├── model/
│   ├── User.java                 ← User data model
│   └── Note.java                 ← Note data model
├── service/
│   ├── AuthService.java          ← BCrypt login / register
│   ├── NoteService.java          ← Encrypted CRUD operations
│   └── EncryptionService.java    ← AES-256-CBC encrypt/decrypt
├── database/
│   └── DBConnection.java         ← SQLite connection + schema
└── ui/
    ├── LoginUI.java              ← Login & register screen
    └── DashboardUI.java          ← Main notes dashboard

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Dependencies (JAR files needed)

Download and place in a lib/ folder:

Library	Purpose	Download
sqlite-jdbc-3.x.x.jar	SQLite database driver	https://github.com/xerial/sqlite-jdbc/releases
jbcrypt-0.4.jar	BCrypt password hashing	https://www.mindrot.org/projects/jBCrypt/

Maven equivalents:

<dependency>
    <groupId>org.xerial</groupId>
    <artifactId>sqlite-jdbc</artifactId>
    <version>3.45.1.0</version>
</dependency>
<dependency>
    <groupId>org.mindrot</groupId>
    <artifactId>jbcrypt</artifactId>
    <version>0.4</version>
</dependency>

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Compilation & Run

Option A — Command Line

# From the project root
javac -cp "lib/*" -d out/ src/**/*.java src/Main.java
java  -cp "lib/*:out/" Main

On Windows:

javac -cp "lib\*" -d out src\**\*.java src\Main.java
java  -cp "lib\*;out" Main

Option B — IntelliJ IDEA

1. File → New Project → Empty Project
2. Add lib/ JARs as dependencies (Project Structure → Libraries)
3. Set Main.java as the Run Configuration entry point
4. Click Run

Option C — Eclipse

1. File → New Java Project
2. Right-click project → Build Path → Add External JARs → select both JARs
3. Right-click Main.java → Run As → Java Application

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Application Flow

Start App
    │
    ▼
Login / Register Screen
    │
    ├─ Register: BCrypt.hashpw(password) → stored in DB
    │
    └─ Login:    BCrypt.checkpw(input, hash)
                    │
                    ▼
              Dashboard
                    │
                    ├─ Add Note → AES-256 encrypt body → save to DB
                    ├─ View Note → load from DB → AES-256 decrypt → show
                    ├─ Edit Note → re-encrypt on save
                    ├─ Delete Note → remove from DB
                    ├─ Search → decrypt in memory → keyword match
                    └─ Logout → dispose window → return to Login

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Security Design

Password Storage (BCrypt)

// Registration — never store plain text
String hash = BCrypt.hashpw(plainPassword, BCrypt.gensalt(12));
// 12 = work factor (2^12 iterations)

// Login — constant-time comparison
boolean ok = BCrypt.checkpw(inputPassword, storedHash);

Note Encryption (AES-256-CBC)

// Key derivation from password
PBKDF2WithHmacSHA256(password, salt, 65536 iterations) → 256-bit AES key

// Per-note encryption
Random IV (16 bytes) → AES/CBC/PKCS5Padding → Base64(IV + ciphertext) → DB

// Decryption
Base64 decode → split IV + ciphertext → AES decrypt → plain text

Database Schema

CREATE TABLE users (
    id            INTEGER PRIMARY KEY AUTOINCREMENT,
    username      TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,   -- BCrypt hash ONLY
    first_name    TEXT NOT NULL,
    last_name     TEXT NOT NULL,
    created_at    DATETIME DEFAULT (datetime('now'))
);

CREATE TABLE notes (
    id         INTEGER PRIMARY KEY AUTOINCREMENT,
    user_id    INTEGER NOT NULL,
    title      TEXT NOT NULL,
    body       TEXT NOT NULL,      -- AES-256 ciphertext ONLY
    category   TEXT DEFAULT 'Personal',
    created_at DATETIME DEFAULT (datetime('now')),
    updated_at DATETIME DEFAULT (datetime('now')),
    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
);

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Features Implemented

Feature	Status
User Registration	✅
BCrypt Password Hashing	✅
User Login	✅
AES-256 Note Encryption	✅
PBKDF2 Key Derivation	✅
SQLite Database	✅
Add / Edit / Delete Notes	✅
Search Notes by Keyword	✅
Categories (Work/Study/Personal)	✅
Created/Updated Timestamps	✅
Auto Logout (5 min inactivity)	✅
Password Strength Checker	✅
Swing GUI	✅
Multi-user Login System	✅

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Java APIs Used

• javax.crypto.* — Java Cryptography Extension (JCE)
• java.security.* — Java Security API
• java.sql.* — JDBC for SQLite
• javax.swing.* — Swing GUI framework
• java.awt.* — AWT layout and events

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Author Notes

Plain-text passwords are NEVER written to disk. Note bodies are encrypted BEFORE leaving memory. The encryption key is derived per-session from the user's password and discarded on logout.