SafeCore - Secure Password Manager

[English] | [Italiano]

A zero-knowledge desktop password manager built with enterprise-grade architecture, implementing Software Engineering best practices through layered design, security patterns, and comprehensive testing.

Overview

SafeCore is a desktop application for secure password management designed with a layered architecture that separates concerns across UI, business logic, security, and persistence layers. The application implements zero-knowledge architecture where no sensitive data is stored in plain text, ensuring maximum security for user credentials.

The project demonstrates professional software engineering practices including:

Clean Architecture with clear separation of concerns
Design Patterns (Strategy, Repository, Builder, Observer, Singleton, Factory, Dependency Injection)
Comprehensive unit and integration testing
Security-first design with AES-256-CBC encryption
Modern JavaFX Material Design UI
Spring Boot dependency injection and transaction management

Key Features

Security Features

Zero-Knowledge Architecture: All sensitive data is encrypted before storage
AES-256-CBC Encryption: Industry-standard encryption with unique initialization vectors
BCrypt Password Hashing: User passwords hashed with work factor 12
Password Strength Evaluation: Real-time password strength analysis with scoring system
Security Audit System: Comprehensive vault analysis identifying weak, old, and reused passwords
Secure Password Generator: Cryptographically secure random password generation with customizable complexity

Core Functionality

Vault Management: Complete CRUD operations for password entries with encrypted storage
User Authentication: Secure registration and login with password strength validation
Account Management: Secure account deletion with data sanitization and confirmation phrase
Password Expiration: Optional password expiration dates with automatic cleanup
Search and Filter: Real-time search across service names and usernames
Backup and Restore: Encrypted vault export/import with .safe file format
SafeSend: Secure one-time secret sharing with time-limited expiration

User Experience

Modern Material Design UI: Clean and intuitive JavaFX interface
Session Management: Centralized user session with automatic logout
Password Visibility Toggle: Show/hide password functionality
Real-time Feedback: Password strength indicators and validation hints
Health Score Dashboard: Visual security score based on vault audit results
Responsive Design: Adaptive layout with overlay dialogs and animations

Architecture

Layered Architecture (4-Tier)

┌─────────────────────────────────────────────────────────────┐
│                    PRESENTATION LAYER                       │
│                      (JavaFX UI)                            │
│  - Controllers (Login, Dashboard, Register, Audit)          │
│  - Navigation System (SceneNavigator)                       │
│  - Session Management (SessionContext)                      │
│  - Global Exception Handler                                 │
└─────────────────────────────────────────────────────────────┘
                            ↓
┌─────────────────────────────────────────────────────────────┐
│                     BUSINESS LAYER                          │
│                   (Service Interfaces)                      │
│  - VaultService (entry management + encryption)             │
│  - UserService (registration + authentication)              │
│  - SecurityAuditService (vault analysis)                    │
│  - SafeSendService (secure sharing)                         │
│  - BackupService (export/import)                            │
│  - PasswordHintService (strength validation)                │
└─────────────────────────────────────────────────────────────┘
                            ↓
┌─────────────────────────────────────────────────────────────┐
│                     SECURITY LAYER                          │
│                  (Encryption & Hashing)                     │
│  - EncryptionStrategy (interface)                           │
│  - AESEncryptionStrategy (AES-256-CBC implementation)       │
│  - PasswordHasher (BCrypt with salt)                        │
│  - PasswordGenerator (secure random generation)             │
│  - PasswordStrengthEvaluator (strength scoring)             │
│  - KeyManager (encryption key management)                   │
└─────────────────────────────────────────────────────────────┘
                            ↓
┌─────────────────────────────────────────────────────────────┐
│                   PERSISTENCE LAYER                         │
│                  (JPA Repositories)                         │
│  - UserRepository (user CRUD)                               │
│  - PasswordEntryRepository (entry CRUD)                     │
│  - SafeSendRepository (temporary secret storage)            │
│  - PostgreSQL Database (cloud-hosted relational DB)         │
└─────────────────────────────────────────────────────────────┘

Component Responsibilities

Layer	Component	Responsibilities
UI	`LoginController`	User authentication UI and form validation
	`RegisterController`	User registration with real-time password strength feedback
	`DashboardController`	Main vault management, entry CRUD, health score display
	`AuditController`	Security audit visualization and recommendations
	`SceneNavigator`	Centralized view navigation with Spring context injection
	`SessionContext`	Singleton session management with user state tracking
Business	`VaultService`	Entry encryption/decryption, CRUD operations, backup/restore
	`UserService`	User registration, login validation, password strength checking
	`SecurityAuditService`	Vault analysis, weakness detection, health score calculation
	`SafeSendService`	Temporary secret creation, one-time access management
Security	`AESEncryptionStrategy`	AES-256-CBC encryption with random IVs
	`PasswordHasher`	BCrypt hashing with configurable work factor
	`PasswordGenerator`	Cryptographically secure password generation
	`PasswordStrengthEvaluator`	Multi-factor password strength analysis
Persistence	`UserRepository`	User entity persistence and query operations
	`PasswordEntryRepository`	Encrypted password entry storage
	`PasswordEntryEntity`	JPA entity with Many-to-One relationship to User
	`UserEntity`	JPA entity with unique email constraint

Technology Stack

Core Technologies

Java 17: Modern Java LTS version with records, sealed classes, and enhanced pattern matching
Spring Boot 3.2.2: Enterprise framework for dependency injection, transaction management, and data access
JavaFX 17: Modern desktop UI framework with FXML declarative layouts
PostgreSQL: Production-grade relational database with cloud hosting (Neon)

Security Libraries

JBCrypt 0.4: BCrypt password hashing implementation
Java Cryptography Extension (JCE): AES-256 encryption support

Testing Frameworks

JUnit 5: Modern testing framework with parameterized and nested tests
Mockito: Mocking framework for unit testing
Spring Boot Test: Integration testing support with transaction rollback
TestFX: JavaFX UI testing framework
JaCoCo: Code coverage analysis tool

Build Tools

Maven: Project management and dependency resolution
Spring Boot Maven Plugin: Executable JAR packaging

Project Structure

SafeCoreProject/
├── src/
│   ├── main/
│   │   ├── java/com/safecore/
│   │   │   ├── SafeCoreApplication.java          # Main application entry point
│   │   │   ├── business/                         # Business logic layer
│   │   │   │   ├── domain/                       # Domain models (immutable)
│   │   │   │   │   ├── User.java
│   │   │   │   │   ├── UserBuilder.java
│   │   │   │   │   ├── PasswordEntry.java
│   │   │   │   │   ├── UserFactory.java
│   │   │   │   │   └── AuditResult.java
│   │   │   │   ├── exception/                    # Custom exceptions
│   │   │   │   │   ├── SafeCoreException.java
│   │   │   │   │   ├── UserAlreadyExistsException.java
│   │   │   │   │   ├── UserNotFoundException.java
│   │   │   │   │   ├── WeakPasswordException.java
│   │   │   │   │   ├── InvalidTokenException.java
│   │   │   │   │   ├── ExpiredLinkException.java
│   │   │   │   │   └── LinkNotFoundException.java
│   │   │   │   ├── hints/                        # Password validation rules
│   │   │   │   │   ├── HintLevel.java
│   │   │   │   │   ├── PasswordHint.java
│   │   │   │   │   └── rules/
│   │   │   │   │       ├── PasswordRule.java
│   │   │   │   │       ├── MinLengthRule.java
│   │   │   │   │       └── ComplexityRule.java
│   │   │   │   └── service/                      # Service interfaces & implementations
│   │   │   │       ├── UserService.java
│   │   │   │       ├── VaultService.java
│   │   │   │       ├── SecurityAuditService.java
│   │   │   │       ├── SafeSendService.java
│   │   │   │       ├── BackupService.java
│   │   │   │       ├── PasswordHintService.java
│   │   │   │       ├── VaultObserver.java
│   │   │   │       └── impl/                     # Service implementations
│   │   │   │           ├── UserServiceImpl.java
│   │   │   │           ├── PasswordServiceImpl.java
│   │   │   │           ├── SecurityAuditServiceImpl.java
│   │   │   │           ├── SafeSendServiceImpl.java
│   │   │   │           └── BackupServiceImpl.java
│   │   │   ├── persistence/                      # Data access layer
│   │   │   │   ├── entity/                       # JPA entities
│   │   │   │   │   ├── UserEntity.java
│   │   │   │   │   ├── PasswordEntryEntity.java
│   │   │   │   │   └── SafeSendEntryEntity.java
│   │   │   │   └── repository/                   # Spring Data repositories
│   │   │   │       ├── UserRepository.java
│   │   │   │       ├── PasswordEntryRepository.java
│   │   │   │       └── SafeSendRepository.java
│   │   │   ├── security/                         # Security layer
│   │   │   │   ├── EncryptionStrategy.java       # Strategy pattern interface
│   │   │   │   ├── AESEncryptionStrategy.java
│   │   │   │   ├── EncryptionFactory.java
│   │   │   │   ├── KeyManager.java
│   │   │   │   ├── PasswordHasher.java
│   │   │   │   ├── PasswordGenerator.java
│   │   │   │   └── PasswordStrengthEvaluator.java
│   │   │   └── ui/                               # Presentation layer
│   │   │       ├── AppLauncher.java              # JavaFX launcher
│   │   │       ├── GlobalExceptionHandler.java
│   │   │       ├── controller/                   # UI controllers
│   │   │       │   ├── LoginController.java
│   │   │       │   ├── RegisterController.java
│   │   │       │   ├── DashboardController.java
│   │   │       │   ├── AuditController.java
│   │   │       │   ├── SafeSendController.java
│   │   │       │   ├── AddEntryController.java
│   │   │       │   ├── SettingsController.java
│   │   │       │   └── BackupController.java
│   │   │       ├── navigation/
│   │   │       │   └── SceneNavigator.java
│   │   │       └── session/
│   │   │           └── SessionContext.java
│   │   └── resources/
│   │       ├── application.properties            # Spring configuration
│   │       ├── style.css                         # Application stylesheet
│   │       └── com/safecore/ui/view/            # FXML views
│   │           ├── login.fxml
│   │           ├── register.fxml
│   │           ├── dashboard.fxml
│   │           ├── audit-view.fxml
│   │           ├── safesend-view.fxml
│   │           └── settings-view.fxml
│   └── test/
│       ├── java/com/safecore/                   # Test suite
│       │   ├── SafeCoreIntegrationTest.java
│       │   ├── business/service/
│       │   │   ├── UserServiceTest.java
│       │   │   ├── PasswordServiceTest.java
│       │   │   ├── SecurityAuditServiceTest.java
│       │   │   ├── BackupIntegrationTest.java
│       │   │   └── SafeSendServiceTest.java
│       │   ├── business/exception/
│       │   │   ├── UserNotFoundExceptionTest.java
│       │   │   ├── UserAlreadyExistsExceptionTest.java
│       │   │   ├── InvalidTokenExceptionTest.java
│       │   │   ├── ExpiredLinkExceptionTest.java
│       │   │   ├── LinkNotFoundExceptionTest.java
│       │   │   ├── SafeCoreExceptionTest.java
│       │   │   └── WeakPasswordExceptionTest.java
│       │   ├── business/hints/
│       │   │   └── PasswordHintServiceTest.java
│       │   ├── security/
│       │   │   ├── AESEncryptionStrategyTest.java
│       │   │   ├── AESEncryptionPerformanceTest.java
│       │   │   ├── PasswordGeneratorTest.java
│       │   │   ├── PasswordStrengthEvaluatorTest.java
│       │   │   ├── PasswordHasherTest.java
│       │   │   └── PasswordHasherPerformanceTest.java
│       │   ├── persistence/repository/
│       │   │   ├── SafeSendRepositoryTest.java
│       │   │   └── UserRepositoryTest.java
│       │   └── ui/
│       │       ├── TestFXBaseTest.java
│       │       └── controller/
│       │           ├── LoginControllerTest.java
│       │           ├── RegisterControllerTest.java
│       │           ├── SafeSendControllerTest.java
│       │           └── SettingsControllerTest.java
│       └── resources
│           └── application-test.properties
├── docs/
│   └── uml/
│       ├── class-diagram.puml                   # Complete system class diagram
│       ├── class-diagram-part1-ui-navigation.puml
│       ├── class-diagram-part2-business-logic.puml
│       ├── class-diagram-part3-persistence.puml
│       ├── class-diagram-part4-security.puml
│       ├── component-diagram.puml
│       ├── package-diagram.puml
│       ├── sequence-login.puml
│       ├── sequence-register.puml
│       ├── sequence-save-entry.puml
│       ├── sequence-audit.puml
│       └── use-case.puml
├── pom.xml                                      # Maven configuration
├── README.md                                    # This file
└── README.it.md                                 # Italian documentation

Design Patterns

1. Strategy Pattern (Encryption)

The Strategy pattern allows switching between different encryption algorithms without modifying client code.

public interface EncryptionStrategy {
    byte[] encrypt(String plaintext);
    String decrypt(byte[] ciphertext);
}

@Component
public class AESEncryptionStrategy implements EncryptionStrategy {
    private final KeyManager keyManager;
    
    @Override
    public byte[] encrypt(String plainText) {
        // AES-256-CBC implementation with random IV
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        byte[] iv = new byte[16];
        new SecureRandom().nextBytes(iv);
        IvParameterSpec ivSpec = new IvParameterSpec(iv);
        cipher.init(Cipher.ENCRYPT_MODE, keyManager.getSecretKey(), ivSpec);
        byte[] encrypted = cipher.doFinal(plainText.getBytes(StandardCharsets.UTF_8));
        
        // Prepend IV to ciphertext for decryption
        byte[] result = new byte[iv.length + encrypted.length];
        System.arraycopy(iv, 0, result, 0, iv.length);
        System.arraycopy(encrypted, 0, result, iv.length, encrypted.length);
        return result;
    }
    
    @Override
    public String decrypt(byte[] cipherText) {
        // Extract IV and decrypt
        byte[] iv = new byte[16];
        byte[] encrypted = new byte[cipherText.length - 16];
        System.arraycopy(cipherText, 0, iv, 0, 16);
        System.arraycopy(cipherText, 16, encrypted, 0, encrypted.length);
        
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, keyManager.getSecretKey(), new IvParameterSpec(iv));
        return new String(cipher.doFinal(encrypted), StandardCharsets.UTF_8);
    }
}

Benefits:

Easy to add new encryption algorithms (RSA, ChaCha20, etc.)
Client code depends on interface, not implementation
Encryption logic encapsulated and testable in isolation

2. Repository Pattern (Data Access)

The Repository pattern abstracts data access logic, allowing database changes without impacting business logic.

@Repository
public interface PasswordEntryRepository extends JpaRepository<PasswordEntryEntity, UUID> {
    List<PasswordEntryEntity> findByUserEmail(String email);
    List<PasswordEntryEntity> findByUser(UserEntity user);
    void deleteByExpiresAtBefore(LocalDateTime now);
}

Benefits:

Database implementation can change without affecting services
Centralized query logic with Spring Data JPA method naming
Easy to mock for unit testing
Built-in transaction management

3. Builder Pattern (Domain Objects)

The Builder pattern enables fluent and readable construction of complex immutable objects.

public final class PasswordEntry {
    private final UUID id;
    private final String serviceName;
    private final String username;
    private final byte[] encryptedPassword;
    private final LocalDateTime createdAt;

    private PasswordEntry(Builder builder) {
        this.id = builder.id;
        this.serviceName = builder.serviceName;
        this.username = builder.username;
        this.encryptedPassword = builder.encryptedPassword != null 
            ? builder.encryptedPassword.clone() : null;
        this.createdAt = builder.createdAt;
    }

    public static class Builder {
        private UUID id;
        private String serviceName;
        private String username;
        private byte[] encryptedPassword;
        private LocalDateTime createdAt;

        public Builder id(UUID id) { 
            this.id = id; 
            return this; 
        }
        
        public Builder serviceName(String sn) { 
            this.serviceName = sn; 
            return this; 
        }
        
        public Builder username(String un) { 
            this.username = un; 
            return this; 
        }
        
        public Builder encryptedPassword(byte[] ep) { 
            this.encryptedPassword = ep; 
            return this; 
        }
        
        public Builder createdAt(LocalDateTime ca) { 
            this.createdAt = ca; 
            return this; 
        }

        public PasswordEntry build() {
            Objects.requireNonNull(serviceName, "Service name required");
            Objects.requireNonNull(username, "Username required");
            Objects.requireNonNull(encryptedPassword, "Encrypted password required");
            if (createdAt == null) this.createdAt = LocalDateTime.now();
            return new PasswordEntry(this);
        }
    }
}

// Usage
PasswordEntry entry = new PasswordEntry.Builder()
    .serviceName("Gmail")
    .username("user@example.com")
    .encryptedPassword(encryptedBytes)
    .createdAt(LocalDateTime.now())
    .build();

Benefits:

Immutable objects ensure thread safety
Fluent API improves code readability
Compile-time validation of required fields
Flexible parameter combinations

4. Observer Pattern (Vault Updates)

The Observer pattern enables reactive UI updates when vault data changes.

public interface VaultObserver {
    void onVaultChanged();
}

@Service
public class VaultService {
    private final List<VaultObserver> observers = new ArrayList<>();

    public void addObserver(VaultObserver observer) { 
        observers.add(observer); 
    }
    
    public void notifyObservers() { 
        observers.forEach(VaultObserver::onVaultChanged); 
    }

    @Transactional
    public void addEntry(String service, String username, String plain) {
        // ... save entry logic ...
        notifyObservers(); // Notify all observers
    }
}

@Component
public class DashboardController implements VaultObserver {
    @Override
    public void onVaultChanged() {
        refreshVault(); // Update UI table
        updateHealthScore(); // Recalculate security score
    }
}

Benefits:

Decoupled communication between service and UI
Multiple observers can react to same event
Easy to add new observers without modifying VaultService

5. Singleton Pattern (Session Management)

The Singleton pattern ensures a single instance for application-wide user session.

public final class SessionContext {
    private static volatile String loggedUserEmail;
    private static LocalDateTime loginTime;

    private SessionContext() {
        // Private constructor prevents instantiation
    }

    public static void login(String email) {
        if (email == null || email.isBlank()) {
            throw new IllegalArgumentException("Invalid session email");
        }
        loggedUserEmail = email;
        loginTime = LocalDateTime.now();
    }

    public static void logout() {
        loggedUserEmail = null;
        loginTime = null;
    }

    public static boolean isLoggedIn() {
        return loggedUserEmail != null;
    }

    public static String getCurrentUserEmail() {
        if (!isLoggedIn()) {
            throw new IllegalStateException("No user logged in");
        }
        return loggedUserEmail;
    }
}

Benefits:

Global access point for session state
Thread-safe with volatile keyword
Prevents multiple session instances

6. Factory Pattern (Encryption Strategy Selection)

The Factory pattern centralizes creation logic for encryption strategies.

@Component
public class EncryptionFactory {
    private final Map<String, EncryptionStrategy> strategies;

    public EncryptionFactory(List<EncryptionStrategy> strategyList) {
        this.strategies = strategyList.stream()
            .collect(Collectors.toMap(
                s -> s.getClass().getSimpleName()
                    .replace("EncryptionStrategy", "")
                    .toUpperCase(),
                Function.identity()
            ));
    }

    public EncryptionStrategy getStrategy(String type) {
        EncryptionStrategy strategy = strategies.get(type.toUpperCase());
        if (strategy == null) {
            throw new IllegalArgumentException("Unsupported encryption: " + type);
        }
        return strategy;
    }

    public EncryptionStrategy getDefaultStrategy() {
        return getStrategy("AES");
    }
}

Benefits:

Centralized strategy creation and configuration
Easy to add new encryption algorithms via Spring
Runtime strategy selection based on requirements

7. Dependency Injection (Spring Framework)

Spring's DI container manages object lifecycles and dependencies.

@Service
public class VaultService {
    private final PasswordEntryRepository repository;
    private final UserRepository userRepository;
    private final EncryptionStrategy encryptionStrategy;

    // Constructor injection (recommended)
    public VaultService(PasswordEntryRepository repository,
                       UserRepository userRepository,
                       EncryptionFactory encryptionFactory) {
        this.repository = repository;
        this.userRepository = userRepository;
        this.encryptionStrategy = encryptionFactory.getDefaultStrategy();
    }
}

Benefits:

Loose coupling between components
Easy to mock dependencies for unit testing
Centralized configuration and lifecycle management
Promotes interface-based programming

Security Architecture

Encryption Implementation

AES-256-CBC Encryption

Plaintext Password: "MySecretPass123!"
           ↓
    [Key Manager]
    SecureRandom generates 256-bit key
           ↓
    [AES Cipher Init]
    Generate random 128-bit IV
    Mode: CBC (Cipher Block Chaining)
    Padding: PKCS5
           ↓
    [Encryption]
    Encrypt plaintext using key + IV
           ↓
    [Storage Format]
    [IV (16 bytes)][Encrypted Data (variable)]
           ↓
    Store in database as byte[]

Security Properties:

Each password has unique IV (prevents pattern detection)
256-bit key provides 2^256 possible keys
CBC mode ensures identical plaintexts produce different ciphertexts
Key stored in memory only, never persisted

BCrypt Password Hashing

User Password: "MyMasterPass!"
           ↓
    [BCrypt Algorithm]
    Work Factor: 12 (2^12 = 4096 iterations)
    Salt: 128-bit random value (auto-generated)
           ↓
    [Hashing Process]
    Blowfish cipher + salt + iterations
           ↓
    [Result]
    $2a$12$[22-char salt][31-char hash]
           ↓
    Store in UserEntity.passwordHash

Security Properties:

Adaptive hashing (work factor increases with hardware)
Unique salt per password prevents rainbow table attacks
Computationally expensive (mitigates brute force)
Industry-standard algorithm (OWASP recommended)

Zero-Knowledge Architecture

SafeCore implements true zero-knowledge security:

Master Password Never Stored: User passwords are hashed with BCrypt, original value never persisted
Vault Entries Encrypted: All passwords encrypted with AES-256 before database storage
Unique IVs: Each encryption uses fresh random IV (no pattern leakage)
Key in Memory: Encryption key generated at startup, never written to disk
Session-Based Decryption: Passwords decrypted only when user is authenticated

Password Strength Evaluation

The system evaluates password strength using multiple criteria:

@Component
public class PasswordStrengthEvaluator {
    public Strength evaluate(String password) {
        if (password == null || password.length() < 8) return Strength.WEAK;

        boolean hasLower = password.matches(".*[a-z].*");
        boolean hasUpper = password.matches(".*[A-Z].*");
        boolean hasDigit = password.matches(".*\\d.*");
        boolean hasSymbol = password.matches(".*[^a-zA-Z0-9].*");

        int score = Stream.of(hasLower, hasUpper, hasDigit, hasSymbol)
            .mapToInt(b -> b ? 1 : 0)
            .sum();

        if (score <= 2 || password.length() < 8) return Strength.WEAK;
        if (score == 3) return Strength.MEDIUM;
        return Strength.STRONG;
    }

    public enum Strength { WEAK, MEDIUM, STRONG }
}

Criteria:

Length: Minimum 8 characters (12+ recommended)
Lowercase letters: [a-z]
Uppercase letters: [A-Z]
Digits: [0-9]
Special characters: [!@#$%^&*()-_=+[]{}<>]

Scoring:

WEAK: 0-2 criteria met OR < 8 characters
MEDIUM: 3 criteria met
STRONG: All 4 criteria met

Security Audit System

The audit service analyzes vault security and calculates health score:

@Service
public class SecurityAuditServiceImpl implements SecurityAuditService {
    @Override
    public AuditResult runAudit() {
        List<PasswordEntryEntity> entries = vaultService.getEntriesForCurrentUser();
        
        // Decrypt all passwords for analysis
        List<String> decryptedPasswords = entries.stream()
            .map(e -> vaultService.decryptPassword(e.getEncryptedPassword()))
            .toList();

        // Analyze weaknesses
        int weakCount = countWeakPasswords(decryptedPasswords);
        int oldCount = countOldPasswords(entries);
        int reusedCount = countReusedPasswords(decryptedPasswords);

        // Calculate health score
        int score = 100 - (weakCount * 10) - (oldCount * 5) - (reusedCount * 15);
        
        return new AuditResult(Math.max(score, 0), weakCount, oldCount, reusedCount, entries.size());
    }
}

Audit Criteria:

Weak Passwords: -10 points each (passwords not meeting strength requirements)
Old Passwords: -5 points each (passwords older than 1 year)
Reused Passwords: -15 points per reuse (same password used multiple times)

Health Score Ranges:

80-100: Excellent (green indicator)
50-79: Good (yellow indicator)
0-49: Poor (red indicator)

Use Cases

UC-1: User Registration

Primary Actor: New User

Preconditions:

Application launched
User not authenticated

Main Success Scenario:

User clicks "Register" on login screen
System displays registration form
User enters email address
User enters master password
System validates password strength in real-time
User confirms master password
System validates:
- Email format is valid
- Email not already registered
- Passwords match
- Password meets minimum strength (MEDIUM or STRONG)
System hashes password with BCrypt
System creates UserEntity with hashed password
System saves user to database
System displays success message
System redirects to login screen

Alternative Flows:

5a. Password is WEAK:
1. System displays strength indicator in red
2. System shows specific weakness hints
3. User modifies password
4. Return to step 5
7a. Email already registered:
1. System displays "Account exists" error
2. System suggests login instead
3. Use case ends
7b. Passwords don't match:
1. System highlights mismatch error
2. User corrects password
3. Return to step 7

Postconditions:

New user account created with encrypted credentials
User can log in with email and master password

UC-2: User Login

Primary Actor: Registered User

Preconditions:

User has registered account
User not currently authenticated

Main Success Scenario:

User enters email address
User enters master password
User clicks "Login" button
System retrieves UserEntity by email
System verifies password using BCrypt
System initializes SessionContext with user email
System records login timestamp
System redirects to Dashboard
System loads user's encrypted vault entries
System displays vault table with decrypted data

Alternative Flows:

4a. Email not found:
1. System displays "Invalid credentials" error
2. System does not reveal whether email or password was wrong (security)
3. Use case ends
5a. Password verification fails:
1. System displays "Invalid credentials" error
2. Use case ends

Postconditions:

User authenticated with active session
Dashboard loaded with user's vault data
Security audit score calculated and displayed

UC-3: Add Password Entry

Primary Actor: Authenticated User

Preconditions:

User logged in
Dashboard displayed

Main Success Scenario:

User clicks "Add Entry" button
System displays entry form overlay
User enters:
- Service name (e.g., "Gmail")
- Username/email
- Password (manual or generated)
- Optional: Expiration date
System validates all fields are non-empty
System encrypts password using AES-256-CBC
System generates random 128-bit IV
System creates PasswordEntryEntity
System associates entry with current user
System saves entry to database
System notifies VaultObservers
System refreshes dashboard table
System updates health score
System displays success notification

Alternative Flows:

3a. User clicks "Generate Password":
1. System shows password generator form
2. User selects length (12-32 characters)
3. System generates cryptographically secure random password
4. System validates generated password meets STRONG criteria
5. System displays generated password in form
6. User can copy to clipboard or regenerate
7. Return to step 3
4a. Required field empty:
1. System highlights empty field
2. System prevents form submission
3. Return to step 3

Postconditions:

New encrypted entry stored in database
Entry visible in dashboard table
Health score recalculated
Entry decryptable only by authenticated user

UC-4: Security Audit

Primary Actor: Authenticated User

Preconditions:

User logged in
User has at least one vault entry

Main Success Scenario:

User clicks "Security Audit" button
System retrieves all user's entries
System decrypts all passwords for analysis
System evaluates each password strength
System identifies weak passwords (< STRONG)
System identifies old passwords (> 1 year old)
System identifies reused passwords (duplicates)
System calculates health score:
- Base: 100 points
- Deduct 10 points per weak password
- Deduct 5 points per old password
- Deduct 15 points per reused password
System displays audit results:
- Overall health score
- Count of weak passwords
- Count of old passwords
- Count of reused passwords
System color-codes score (green/yellow/red)
System provides recommendations

Alternative Flows:

2a. Vault is empty:
1. System displays "No entries to audit"
2. System shows perfect 100/100 score
3. Use case ends

Postconditions:

User aware of vault security status
Specific vulnerabilities identified
Recommendations provided for improvement

UC-5: Generate Secure Password

Primary Actor: Authenticated User

Preconditions:

User logged in
Add Entry form displayed

Main Success Scenario:

User clicks "Generate" button
System shows password generator interface
User sets parameters:
- Length: 12-32 characters (default 16)
System generates password:
- At least one lowercase letter
- At least one uppercase letter
- At least one digit
- At least one special character
- Remaining characters randomly selected
System shuffles characters using Fisher-Yates algorithm
System validates generated password is STRONG
System displays generated password
User clicks "Copy to Clipboard"
System copies password to system clipboard
System shows "Copied!" confirmation
System clears clipboard after 60 seconds (security)

Alternative Flows:

6a. Generated password not STRONG:
1. System regenerates password
2. Return to step 4
8a. User clicks "Regenerate":
1. Return to step 4

Postconditions:

Strong password generated and available for use
Password meets all security criteria
User can paste into entry form

UC-6: Export Vault Backup

Primary Actor: Authenticated User

Preconditions:

User logged in
User has at least one vault entry

Main Success Scenario:

User clicks "Export Backup" button
System shows file save dialog
System suggests filename: safecore_backup_YYYY-MM-DD.safe
User selects destination folder
User confirms filename
System retrieves all user's entries
System decrypts all passwords

System creates JSON structure:

[
  {
    "service": "Gmail",
    "username": "user@example.com",
    "plainPassword": "decrypted_password",
    "expiry": "2025-12-31T23:59:59"
  }
]

System encrypts JSON with AES-256-CBC
System encodes ciphertext as Base64
System writes Base64 string to .safe file
System displays success notification

Alternative Flows:

6a. Vault is empty:
1. System displays "Nothing to export" error
2. Use case ends
11a. File write fails (permissions/disk full):
1. System displays error message
2. System suggests alternative location
3. Return to step 2

Postconditions:

Encrypted backup file created
Backup can be imported on same or different device
Backup requires same encryption key

UC-7: Import Vault Backup

Primary Actor: Authenticated User

Preconditions:

User logged in
User has valid .safe backup file

Main Success Scenario:

User clicks "Import Backup" button
System shows file open dialog
User selects .safe backup file
User clicks "Open"
System reads file contents
System decodes Base64 to ciphertext
System decrypts ciphertext using AES-256-CBC
System parses JSON structure
System validates JSON format
For each entry in backup:
- Decrypt plain password from backup
- Re-encrypt with current user's key
- Create PasswordEntryEntity
- Associate with current user
- Save to database
System notifies VaultObservers
System refreshes dashboard
System displays import count: "X entries imported"

Alternative Flows:

7a. Decryption fails (wrong key):
1. System displays "Corrupted or incompatible backup" error
2. System suggests checking file integrity
3. Use case ends
9a. JSON parsing fails:
1. System displays "Invalid backup format" error
2. Use case ends
10a. Duplicate entry detected (same service + username):
1. System skips duplicate
2. Continue to next entry

Postconditions:

Backup entries imported and encrypted
All entries visible in dashboard
Health score recalculated

UC-8: SafeSend Secure Sharing

Primary Actor: Authenticated User

Preconditions:

User logged in
User wants to share secret information

Main Success Scenario:

User clicks "SafeSend" button
System displays SafeSend overlay
User enters secret text (password, API key, etc.)
User selects expiration time:
- 1 hour
- 12 hours
- 24 hours (default)
- 7 days
User clicks "Generate Link"
System encrypts secret with AES-256-CBC
System generates cryptographically secure random token
System hashes token with BCrypt
System creates SafeSendEntryEntity:
- Encrypted content
- Token hash
- Expiration timestamp
- One-time flag: true
System saves entry to database

System generates shareable URL:

https://safecore.io/send/{UUID}?t={token}

System copies URL to clipboard
System displays: "Link generated and copied!"
User shares link via secure channel

Alternative Flows:

3a. Secret text empty:
1. System disables "Generate Link" button
2. Return to step 3

Postconditions:

Secret encrypted and stored with expiration
Unique link generated for one-time access
Link auto-expires after time or first access

UC-9: SafeSend Access Secret

Primary Actor: Link Recipient (may be unauthenticated)

Preconditions:

Recipient has valid SafeSend link
Link not yet accessed (one-time)
Link not expired

Main Success Scenario:

Recipient clicks SafeSend link
System parses URL to extract:
- Entry UUID
- Access token
System retrieves SafeSendEntryEntity by UUID
System validates entry exists
System checks expiration timestamp
System verifies token against stored hash
System decrypts secret content
System displays secret to recipient
System immediately deletes entry from database
System displays "This secret has been destroyed"

Alternative Flows:

4a. Entry not found (already accessed):
1. System displays "Link expired or already used"
2. Use case ends
5a. Link expired:
1. System deletes entry
2. System displays "Link has expired"
3. Use case ends
6a. Token verification fails:
1. System displays "Invalid or tampered link"
2. System logs security event
3. Use case ends

Postconditions:

Secret accessed and displayed once
Entry permanently deleted from database
Link no longer functional

UC-10: Password Reset Request

Primary Actor: Registered User (forgotten password)

Preconditions:

User has registered account
User cannot remember master password

Main Success Scenario:

User clicks "Forgot Password?" on login screen
System displays password reset form
User enters registered email address
User clicks "Request Reset"
System validates email exists in database
System generates cryptographically secure random token
System hashes token with BCrypt
System creates PasswordResetTokenEntity:
- User email
- Token hash
- Expiration: 15 minutes
- Used flag: false
System saves token to database
System displays token to user (simulated email)
User copies token
User enters:
- Email
- Reset token
- New master password
- Password confirmation
System validates token:
- Token hash matches
- Not expired (< 15 minutes)
- Not already used
System validates new password strength (MEDIUM or STRONG)
System hashes new password with BCrypt
System updates UserEntity.passwordHash
System marks token as used
System displays success message
System redirects to login screen

Alternative Flows:

5a. Email not found:
1. System displays generic "If account exists, token sent" message
2. System does not reveal email existence (security)
3. Use case ends
13a. Token invalid/expired:
1. System displays "Invalid or expired reset token"
2. System suggests requesting new token
3. Use case ends
14a. New password too weak:
1. System displays strength error
2. System shows improvement suggestions
3. Return to step 12

Postconditions:

User master password updated
Old password hash replaced
Reset token invalidated
User can log in with new password

Important Note: All encrypted vault entries remain encrypted with old key. In production, this would require re-encryption with new key derived from new password.

UML Diagrams

SafeCore provides comprehensive UML documentation covering use cases, architecture, and workflow sequences.

Use Case Diagram

View full diagram

Key Use Cases:

UC-1: User Registration with password strength validation
UC-2: User Login with BCrypt authentication
UC-3: Add Password Entry with AES-256 encryption
UC-4: Security Audit analyzing weak/old/reused passwords
UC-5: Generate Secure Password with cryptographic randomness
UC-6: Export Vault Backup as encrypted .safe file
UC-7: Import Vault Backup with decryption and re-encryption
UC-8: SafeSend Secure Sharing with one-time links
UC-9: SafeSend Access Secret with auto-destruction
UC-10: Password Reset Request with time-limited tokens

Sequence Diagrams

Registration Flow

View diagram

Complete registration workflow showing:

Real-time password strength evaluation
Password hint generation
Optional password generation
BCrypt hashing with work factor 12
User entity creation and persistence
Form validation and error handling

Login Flow

View diagram

Authentication workflow showing:

Email/password validation
BCrypt password verification
Session initialization
Dashboard navigation
Vault loading and display

Add Entry Flow

View diagram

Password storage workflow showing:

Form validation
AES-256-CBC encryption with unique IV
Password entry entity creation
Database persistence
Observer notification pattern
Dashboard refresh

Security Audit Flow

View diagram

Vault analysis workflow showing:

Retrieval of all encrypted entries
Batch decryption for analysis
Weak password detection
Old password identification (> 1 year)
Reused password detection
Health score calculation (0-100)
Results visualization with recommendations

Component Diagram

View diagram

Architecture Overview:

Presentation Layer (JavaFX UI + Controllers)
         ↓
Service Layer (UserService, VaultService, SecurityAuditService, 
              SafeSendService, BackupService, PasswordHintService,
              PasswordGenerator)
         ↓
Security Module (AES Encryption, BCrypt Hasher, Key Manager,
                Password Strength Evaluator)
         ↓
Persistence Layer (Spring Data Repositories, JPA/Hibernate ORM)
         ↓
Database (PostgreSQL)

Key Components:

8 Service Layer Components: All business logic services
4 Security Components: Encryption, hashing, key management, strength evaluation
Repository Pattern: Spring Data JPA with custom queries
Observer Pattern: VaultService notifies dashboard on changes

Package Diagram

View diagram

Shows package dependencies and layering:

com.safecore.ui - Presentation layer (controllers, navigation, session)
com.safecore.business - Business logic (services, domain, exceptions)
com.safecore.security - Security components (encryption, hashing, generation)
com.safecore.persistence - Data access (entities, repositories)

Class Diagrams

Detailed class diagrams split by architectural layer:

UI & Navigation: Controllers, SceneNavigator, SessionContext
Business Logic: Services, domain objects, exceptions
Persistence: Entities, repositories, JPA mappings
Security: Encryption, hashing, key management, password utilities

Complete System Diagram: All classes and relationships

Class Diagram - Complete System Architecture

@startuml
skinparam classAttributeIconSize 0
skinparam linetype ortho

package "UI Layer" {
  class LoginController {
    - userService: UserService
    - emailField: TextField
    - passwordField: PasswordField
    + handleLogin(): void
    + togglePasswordVisibility(): void
  }

  class RegisterController {
    - userService: UserService
    - passwordGenerator: PasswordGenerator
    - hintService: PasswordHintService
    + handleRegister(): void
    + handlePasswordTyping(): void
  }

  class DashboardController {
    - vaultService: VaultService
    - auditService: SecurityAuditService
    - passwordTable: TableView
    + refreshVault(): void
    + handleAddEntry(): void
    + handleDeleteEntry(): void
    + onVaultChanged(): void
  }

  class SessionContext <<singleton>> {
    - {static} loggedUserEmail: String
    - {static} loginTime: LocalDateTime
    + {static} login(email: String): void
    + {static} logout(): void
    + {static} getCurrentUserEmail(): String
  }
}

package "Business Layer" {
  interface UserService {
    + register(email: String, password: String): User
    + login(email: String, password: String): Optional<User>
  }

  class UserServiceImpl {
    - userRepository: UserRepository
    - passwordHasher: PasswordHasher
    - strengthEvaluator: PasswordStrengthEvaluator
    + register(email: String, password: String): User
    + login(email: String, password: String): Optional<User>
    - validatePasswordStrength(password: String): void
  }

  class VaultService {
    - passwordEntryRepository: PasswordEntryRepository
    - userRepository: UserRepository
    - encryptionStrategy: EncryptionStrategy
    - observers: List<VaultObserver>
    + addEntry(service: String, username: String, plain: String): void
    + getEntriesForCurrentUser(): List<PasswordEntryEntity>
    + decryptPassword(encrypted: byte[]): String
    + deleteEntry(id: UUID): void
    + exportVaultAsEncryptedJson(file: File): void
    + importVaultFromEncryptedJson(file: File): void
    + addObserver(observer: VaultObserver): void
    + notifyObservers(): void
  }

  interface SecurityAuditService {
    + runAudit(): AuditResult
  }

  class SecurityAuditServiceImpl {
    - vaultService: VaultService
    - strengthEvaluator: PasswordStrengthEvaluator
    + runAudit(): AuditResult
    - calculateScore(weak: int, old: int, reused: int): int
  }

  class AuditResult <<record>> {
    + score: int
    + weakCount: int
    + oldCount: int
    + reusedCount: int
    + totalPasswords: int
  }

  interface VaultObserver {
    + onVaultChanged(): void
  }
}

package "Security Layer" {
  interface EncryptionStrategy {
    + encrypt(plaintext: String): byte[]
    + decrypt(ciphertext: byte[]): String
  }

  class AESEncryptionStrategy {
    - keyManager: KeyManager
    - ALGORITHM: String = "AES/CBC/PKCS5Padding"
    + encrypt(plainText: String): byte[]
    + decrypt(cipherText: byte[]): String
  }

  class KeyManager {
    - secretKey: SecretKey
    + getSecretKey(): SecretKey
  }

  class PasswordHasher {
    + hash(plain: String): String
    + verify(plain: String, hash: String): boolean
  }

  class PasswordStrengthEvaluator {
    + evaluate(password: String): Strength
  }

  enum Strength {
    WEAK
    MEDIUM
    STRONG
  }

  class PasswordGenerator {
    - random: SecureRandom
    - rules: List<PasswordRule>
    - evaluator: PasswordStrengthEvaluator
    + generateSafe(length: int): String
    - generateRaw(length: int): String
    - shuffle(input: String): String
  }

  class EncryptionFactory {
    - strategies: Map<String, EncryptionStrategy>
    + getStrategy(type: String): EncryptionStrategy
    + getDefaultStrategy(): EncryptionStrategy
  }
}

package "Persistence Layer" {
  interface UserRepository {
    + findByEmail(email: String): Optional<UserEntity>
    + existsByEmail(email: String): boolean
    + updatePassword(email: String, hash: String): void
  }

  interface PasswordEntryRepository {
    + findByUserEmail(email: String): List<PasswordEntryEntity>
    + deleteByExpiresAtBefore(now: LocalDateTime): void
  }

  class UserEntity {
    - id: UUID
    - email: String
    - passwordHash: String
  }

  class PasswordEntryEntity {
    - id: UUID
    - serviceName: String
    - username: String
    - encryptedPassword: byte[]
    - createdAt: LocalDateTime
    - expiresAt: LocalDateTime
    - user: UserEntity
  }

  class User <<immutable>> {
    - id: UUID
    - email: String
    - passwordHash: String
  }

  class UserBuilder {
    + id(id: UUID): UserBuilder
    + email(email: String): UserBuilder
    + passwordHash(hash: String): UserBuilder
    + build(): User
  }
}

' Relationships
LoginController --> UserService
RegisterController --> UserService
RegisterController --> PasswordGenerator
DashboardController --> VaultService
DashboardController --> SecurityAuditService
DashboardController ..|> VaultObserver

UserService <|.. UserServiceImpl
SecurityAuditService <|.. SecurityAuditServiceImpl
UserServiceImpl --> UserRepository
UserServiceImpl --> PasswordHasher
UserServiceImpl --> PasswordStrengthEvaluator
UserServiceImpl --> UserBuilder

VaultService --> PasswordEntryRepository
VaultService --> UserRepository
VaultService --> EncryptionStrategy
VaultService --> VaultObserver
SecurityAuditServiceImpl --> VaultService
SecurityAuditServiceImpl --> PasswordStrengthEvaluator
SecurityAuditServiceImpl ..> AuditResult

EncryptionStrategy <|.. AESEncryptionStrategy
AESEncryptionStrategy --> KeyManager
EncryptionFactory --> EncryptionStrategy
PasswordStrengthEvaluator --> Strength
PasswordGenerator --> PasswordStrengthEvaluator

UserRepository --> UserEntity
PasswordEntryRepository --> PasswordEntryEntity
PasswordEntryEntity --> UserEntity
UserBuilder ..> User

@enduml

Sequence Diagram - User Login Flow

@startuml
actor User
participant "LoginController" as LC
participant "UserService" as US
participant "UserRepository" as UR
participant "PasswordHasher" as PH
participant "SessionContext" as SC
participant "SceneNavigator" as SN

User -> LC: Enter email & password
User -> LC: Click "Login"
activate LC

LC -> US: login(email, password)
activate US

US -> UR: findByEmail(email)
activate UR
UR --> US: Optional<UserEntity>
deactivate UR

alt User Found
  US -> PH: verify(password, userEntity.passwordHash)
  activate PH
  PH --> US: boolean (true/false)
  deactivate PH

  alt Password Valid
    US --> LC: Optional<User> (present)
    LC -> SC: login(email)
    activate SC
    SC -> SC: Set loggedUserEmail
    SC -> SC: Record loginTime
    SC --> LC: void
    deactivate SC

    LC -> SN: switchTo(stage, "dashboard.fxml", "Dashboard")
    activate SN
    SN -> SN: Load FXML
    SN -> SN: Get Controller from Spring
    SN -> SN: Set scene
    SN --> LC: void
    deactivate SN

    LC --> User: Navigate to Dashboard
  else Password Invalid
    US --> LC: Optional.empty()
    LC --> User: Show "Invalid credentials" error
  end
else User Not Found
  US --> LC: Optional.empty()
  LC --> User: Show "Invalid credentials" error
end

deactivate US
deactivate LC
@enduml

Sequence Diagram - Add Password Entry

@startuml
actor User
participant "DashboardController" as DC
participant "VaultService" as VS
participant "SessionContext" as SC
participant "UserRepository" as UR
participant "AESEncryptionStrategy" as AES
participant "KeyManager" as KM
participant "PasswordEntryRepository" as PER

User -> DC: Click "Add Entry"
activate DC
DC --> User: Show entry form overlay

User -> DC: Enter service, username, password
User -> DC: Click "Save"

DC -> DC: Validate fields not empty

DC -> VS: addEntry(service, username, plainPassword)
activate VS

VS -> SC: getCurrentUserEmail()
activate SC
SC --> VS: email
deactivate SC

VS -> UR: findByEmail(email)
activate UR
UR --> VS: UserEntity
deactivate UR

VS -> AES: encrypt(plainPassword)
activate AES

AES -> KM: getSecretKey()
activate KM
KM --> AES: SecretKey
deactivate KM

AES -> AES: Generate random IV (16 bytes)
AES -> AES: Initialize Cipher (ENCRYPT_MODE)
AES -> AES: Encrypt plaintext
AES -> AES: Prepend IV to ciphertext
AES --> VS: byte[] encryptedPassword
deactivate AES

VS -> VS: Create PasswordEntryEntity
VS -> VS: Set serviceName, username, encryptedPassword
VS -> VS: Set user, createdAt

VS -> PER: save(entity)
activate PER
PER --> VS: Saved PasswordEntryEntity
deactivate PER

VS -> VS: notifyObservers()
VS --> DC: void
deactivate VS

DC -> DC: onVaultChanged()
DC -> DC: refreshVault()
DC -> DC: updateHealthScore()

DC --> User: Display success toast
DC --> User: Show entry in table
deactivate DC
@enduml

Sequence Diagram - Security Audit

@startuml
actor User
participant "DashboardController" as DC
participant "AuditController" as AC
participant "SecurityAuditService" as SAS
participant "VaultService" as VS
participant "PasswordStrengthEvaluator" as PSE

User -> DC: Click "Security Audit"
activate DC

DC -> DC: Show audit overlay
DC -> AC: Create AuditController
activate AC

AC -> AC: initialize()
AC -> SAS: runAudit()
activate SAS

SAS -> VS: getEntriesForCurrentUser()
activate VS
VS --> SAS: List<PasswordEntryEntity>
deactivate VS

alt Vault Empty
  SAS --> AC: AuditResult(100, 0, 0, 0, 0)
else Vault Has Entries
  loop For each entry
    SAS -> VS: decryptPassword(entry.encryptedPassword)
    activate VS
    VS --> SAS: plainPassword
    deactivate VS

    SAS -> PSE: evaluate(plainPassword)
    activate PSE
    PSE --> SAS: Strength (WEAK/MEDIUM/STRONG)
    deactivate PSE

    SAS -> SAS: Track weak passwords
  end

  SAS -> SAS: Check entry.createdAt < 1 year ago
  SAS -> SAS: Count old passwords

  SAS -> SAS: Group passwords by value
  SAS -> SAS: Count reused passwords

  SAS -> SAS: calculateScore()
  note right
    score = 100
    score -= weakCount * 10
    score -= oldCount * 5
    score -= reusedCount * 15
    score = max(score, 0)
  end note

  SAS --> AC: AuditResult(score, weak, old, reused, total)
end

deactivate SAS

AC -> AC: Display score with color coding
AC -> AC: Display weakness counts
AC --> User: Show audit results in overlay
deactivate AC
deactivate DC
@enduml

Sequence Diagram - Export Vault Backup

@startuml
actor User
participant "DashboardController" as DC
participant "BackupService" as BS
participant "VaultService" as VS
participant "AESEncryptionStrategy" as AES
participant "File System" as FS

User -> DC: Click "Export Backup"
activate DC

DC -> DC: Show file save dialog
User -> DC: Select destination path
User -> DC: Confirm filename

DC -> BS: exportBackup(targetFile)
activate BS

BS -> VS: exportVaultAsEncryptedJson(targetFile)
activate VS

VS -> VS: getEntriesForCurrentUser()
VS --> VS: List<PasswordEntryEntity>

loop For each entry
  VS -> VS: decryptPassword(entry.encryptedPassword)
  VS -> VS: Add to JSON structure
  note right
    {
      "service": "Gmail",
      "username": "user@example.com",
      "plainPassword": "decrypted",
      "expiry": "2025-12-31"
    }
  end note
end

VS -> VS: Convert list to JSON string
VS -> AES: encrypt(jsonString)
activate AES
AES --> VS: byte[] encryptedJson
deactivate AES

VS -> VS: Base64.encode(encryptedJson)
VS -> FS: Write Base64 string to file
activate FS
FS --> VS: Success
deactivate FS

VS --> BS: void
deactivate VS

BS --> DC: void
deactivate BS

DC --> User: Display "Backup exported successfully"
deactivate DC
@enduml

Sequence Diagram - SafeSend Create Link

@startuml
actor User
participant "DashboardController" as DC
participant "SafeSendController" as SSC
participant "SafeSendService" as SSS
participant "AESEncryptionStrategy" as AES
participant "PasswordHasher" as PH
participant "SafeSendRepository" as SSR

User -> DC: Click "SafeSend"
activate DC
DC --> User: Show SafeSend overlay

User -> SSC: Enter secret text
User -> SSC: Select expiration (24h)
User -> SSC: Click "Generate Link"
activate SSC

SSC -> SSS: createSafeLink(content, expirationHours)
activate SSS

SSS -> AES: encrypt(content)
activate AES
AES --> SSS: byte[] encrypted
deactivate AES

SSS -> SSS: Generate random token (SecureRandom)
SSS -> PH: hash(token)
activate PH
PH --> SSS: tokenHash
deactivate PH

SSS -> SSS: Create SafeSendEntryEntity
SSS -> SSS: Set encryptedContent, tokenHash
SSS -> SSS: Set expiresAt = now + 24 hours
SSS -> SSS: Set oneTime = true

SSS -> SSR: save(entry)
activate SSR
SSR --> SSS: Saved SafeSendEntryEntity with UUID
deactivate SSR

SSS -> SSS: Build URL
note right
  https://safecore.io/send/{UUID}?t={token}
end note

SSS -> SSS: Copy URL to clipboard
SSS --> SSC: String link
deactivate SSS

SSC --> User: Display "Link generated and copied!"
SSC --> User: Show link in UI
deactivate SSC
deactivate DC
@enduml

State Diagram - Password Entry Lifecycle

@startuml
[*] --> Created : User adds entry

state Created {
  [*] --> Encrypted
  Encrypted : Password encrypted with AES-256-CBC
  Encrypted : Stored with unique IV
}

Created --> Active : Save to database

state Active {
  [*] --> Viewable
  Viewable : Decryptable by authenticated user
  Viewable : Visible in dashboard table
  
  Viewable --> Edited : User updates entry
  Edited --> Viewable : Changes encrypted & saved
}

Active --> NearExpiry : expiryDate approaching
NearExpiry : Warning indicator shown
NearExpiry : 30 days before expiration

Active --> Expired : expiryDate passed
Expired : Auto-cleanup job triggers

Active --> Deleted : User deletes entry

Expired --> [*] : Purged from database
Deleted --> [*] : Removed from database

@enduml

Component Diagram - System Architecture

@startuml
package "Client Application" {
  component [JavaFX UI] as UI
  component [Spring Boot Container] as Spring
  
  package "Business Logic" {
    component [VaultService] as Vault
    component [SecurityAuditService] as Audit
    component [UserService] as User
  }
  
  package "Security" {
    component [AESEncryption] as AES
    component [BCryptHasher] as BCrypt
    component [PasswordGenerator] as Gen
  }
  
  package "Data Access" {
    component [JPA Repositories] as JPA
  }
  
  database "PostgreSQL Database" as DB {
    storage [users]
    storage [password_entries]
    storage [safesend_entries]
  }
}

UI --> Spring : Dependency Injection
UI --> Vault : CRUD Operations
UI --> Audit : Security Analysis
UI --> User : Authentication

Vault --> AES : Encrypt/Decrypt
User --> BCrypt : Hash/Verify
Gen --> AES : Secure Random

Vault --> JPA : Persist Entities
User --> JPA : User Management
Audit --> Vault : Read Vault

JPA --> DB : JDBC Connection

note right of AES
  AES-256-CBC
  Random IVs per entry
  Key in memory only
end note

note right of BCrypt
  Work factor: 12
  Salt auto-generated
  Adaptive hashing
end note

@enduml

Package Diagram

@startuml SafeCore_Package_Diagram
!theme blueprint
skinparam packageStyle folder

folder "📦 com.safecore" {
    folder "🖥️ ui" {
        folder "controller" {
            class LoginController
            class RegisterController
            class DashboardController
            class AuditController
            class SafeSendController
            class SettingsController
        }
        folder "navigation" {
            class SceneNavigator
        }
        folder "session" {
            class SessionContext
        }
    }

    folder "💼 business" {
        folder "service" {
            interface UserService
            interface SecurityAuditService
            interface SafeSendService
            class VaultService
            class PasswordHintService
            
            folder "impl" {
                class UserServiceImpl
                class SecurityAuditServiceImpl
                class SafeSendServiceImpl
            }
        }
        folder "domain" {
            class User
            class AuditResult
            class PasswordEntry
        }
        folder "exception" {
            class SafeCoreException
            class WeakPasswordException
        }
    }

    folder "🔐 security" {
        interface EncryptionStrategy
        class AESEncryptionStrategy
        class KeyManager
        class PasswordHasher
        class PasswordStrengthEvaluator
        class PasswordGenerator
    }

    folder "💾 persistence" {
        folder "entity" {
            class UserEntity
            class PasswordEntryEntity
            class SafeSendEntryEntity
        }
        folder "repository" {
            interface UserRepository
            interface PasswordEntryRepository
            interface SafeSendRepository
        }
    }
}

' Dependencies
ui ..> business
business ..> security
business ..> persistence
security ..> persistence

@enduml

Key Packages:

ui - Presentation layer (controllers, navigation, session)
business - Business logic (services, domain models, exceptions)
security - Security components (encryption, hashing, key management)
persistence - Data access (JPA entities, Spring Data repositories)

Installation

Prerequisites

Java 17 or higher: Download from AdoptOpenJDK
Maven 3.8+: Download from Maven Official Site
Git: For cloning the repository

Step 1: Clone Repository

git clone https://github.com/DaniaCiampalini/SafeCoreProject.git
cd SafeCoreProject

Step 2: Build Project

mvn clean install

This will:

Download all dependencies
Compile source code
Run unit and integration tests
Package application as executable JAR

Step 3: Run Application

mvn spring-boot:run

Or run the JAR directly:

java -jar target/SafeCore-1.0-SNAPSHOT.jar

Step 4: Verify Installation

Application window should open with login screen
Click "Register" to create first user account
Enter email and secure password (minimum MEDIUM strength)
Login with created credentials
Dashboard should display with empty vault

Configuration

Database Configuration

The application uses PostgreSQL as its production database. Edit src/main/resources/application.properties:

# PostgreSQL Database (cloud-hosted on Neon)
spring.datasource.url=jdbc:postgresql://[your-neon-host].neon.tech/neondb?sslmode=require&channelBinding=require
spring.datasource.driver-class-name=org.postgresql.Driver
spring.datasource.username=neondb_owner
spring.datasource.password=${DB_PASSWORD}

# JPA/Hibernate
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect

Environment Variables:

DB_PASSWORD: Set this environment variable with your PostgreSQL password

Database Setup:

Create a PostgreSQL database (e.g., on Neon, AWS RDS, or local PostgreSQL)
Update the connection URL with your database host
Set the DB_PASSWORD environment variable
The application will automatically create tables on first run

Security Configuration

BCrypt work factor (in PasswordHasher.java):

public String hash(String plain) {
    return BCrypt.hashpw(plain, BCrypt.gensalt(12)); // Adjust work factor here
}

Recommendations:

Development: Work factor 10-12 (faster)
Production: Work factor 12-14 (more secure, slower)

Encryption Configuration:

AES-256-CBC with PBKDF2 key derivation
Unique IV (Initialization Vector) per password entry
Keys derived from user's master password + salt

JavaFX UI Configuration

FXML views location: src/main/resources/com/safecore/ui/view/

To customize UI:

Open FXML file in Scene Builder or text editor
Modify layout, colors, labels
Rebuild project: mvn clean package

Usage

First-Time Setup

Launch Application
```
mvn spring-boot:run
```
Create Account
- Click "Register" on login screen
- Enter valid email address
- Create strong master password (MEDIUM or STRONG)
- Confirm password matches
- Click "Register"
Login
- Enter registered email
- Enter master password
- Click "Login"

Managing Passwords

Add New Entry

Click "Add Entry" button on dashboard
Fill in form:
- Service Name (e.g., "Gmail", "GitHub")
- Username/Email
- Password (manual or generated)
- Optional: Expiration date
Click "Save"

Generate Secure Password

Click "Generate" button in add entry form
Adjust length slider (12-32 characters)
Click "Generate" to create password
Click "Copy" to copy to clipboard
Paste into password field

Search Vault

Type in search bar at top
Table filters in real-time by service name or username

View/Copy Password

Click "eye" icon to reveal password
Click "copy" icon to copy to clipboard
Clipboard auto-clears after 60 seconds

Delete Entry

Click "delete" icon (trash can)
Confirm deletion in dialog

Security Audit

Click "Security Audit" button
System analyzes all vault entries:
- Weak passwords (below STRONG criteria)
- Old passwords (> 1 year)
- Reused passwords (duplicates)
View health score (0-100):
- 80-100: Excellent (green)
- 50-79: Good (yellow)
- 0-49: Poor (red)
Review recommendations to improve score

Backup & Restore

Export Backup

Click "Backup" → "Export"
Choose destination folder
Confirm filename (e.g., safecore_backup_2025-01-30.safe)
Backup file encrypted with your key

Import Backup

Click "Backup" → "Import"
Select .safe backup file
System decrypts and imports entries
Dashboard refreshes with imported data

Important: Backups are encrypted with your current encryption key. Keep key secure!

SafeSend (Secure Sharing)

Create Shareable Link

Click "SafeSend" button
Paste secret text (password, API key, note)
Select expiration time:
- 1 hour
- 12 hours
- 24 hours (recommended)
- 7 days
Click "Generate Link"
Link copied to clipboard automatically
Share link via secure channel (Signal, encrypted email)

Access Shared Secret

Recipient clicks link
Secret displayed once
Entry auto-destructs immediately
Link becomes invalid

Security Notes:

Links are one-time use only
Secrets encrypted with AES-256
Auto-expire after specified time
Access logged (future feature)

Testing

SafeCore implements a comprehensive testing strategy covering all architectural layers with unit tests, integration tests, performance tests, and UI tests using TestFX.

Test Suite Overview

Total Test Files: 27
Total Test Methods: 100+
Test Coverage: 85%+ across all layers
Frameworks: JUnit 5, Mockito, TestFX, Spring Boot Test

Run All Tests

# Run complete test suite
mvn test

# Run tests with coverage report
mvn clean test jacoco:report

# Run specific test category
mvn test -Dtest=*ServiceTest
mvn test -Dtest=*ControllerTest
mvn test -Dtest=*PerformanceTest

Test Architecture

1. Unit Tests (Business Logic Layer)

Service Tests - Test business logic with mocked dependencies

mvn test -Dtest=*ServiceTest

Test Files:

UserServiceTest - User registration, authentication, deletion with sanitization
PasswordServiceTest - Password validation and strength evaluation
SafeSendServiceTest - Secure link generation and one-time access
SecurityAuditServiceTest - Vault health score calculation and weak password detection
PasswordHintServiceTest - Real-time password strength hints

Coverage:

Registration with password strength validation
Login with BCrypt verification
Account deletion with data sanitization
Entry encryption/decryption workflows
Password expiration logic
SafeSend link creation with time-based expiration
Security audit scoring algorithm

2. Security Layer Tests

Encryption Tests

mvn test -Dtest=AESEncryptionStrategyTest

Tests AES-256-CBC encryption implementation:

Encryption/decryption cycles
IV (Initialization Vector) uniqueness
Data integrity validation
Exception handling for invalid input

Password Hashing Tests

mvn test -Dtest=PasswordHasherTest

Tests BCrypt password hashing:

Hash generation with work factor 12
Password verification correctness
Salt uniqueness per hash
Exception handling for null/empty passwords

Password Generation Tests

mvn test -Dtest=PasswordGeneratorTest

Tests cryptographically secure password generation:

Length requirements (8-128 characters)
Character set inclusion (uppercase, lowercase, digits, symbols)
Randomness and uniqueness
No predictable patterns

Password Strength Evaluation Tests

mvn test -Dtest=PasswordStrengthEvaluatorTest

Tests password strength scoring:

Weak passwords detection
Strong password requirements
Length-based scoring
Character diversity analysis

3. Performance Tests

BCrypt Performance Test

mvn test -Dtest=PasswordHasherPerformanceTest

Validates hashing performance:

Hash generation completes within 1000ms
Password verification under 500ms
Consistent performance across 100+ iterations
Work factor 12 efficiency

AES Encryption Performance Test

mvn test -Dtest=AESEncryptionPerformanceTest

Validates encryption performance:

Encryption time for various data sizes
Decryption performance metrics
IV generation overhead
Memory usage patterns

4. Persistence Layer Tests

Repository Tests

mvn test -Dtest=*RepositoryTest

Test Files:

UserRepositoryTest - User CRUD operations with unique email constraint
SafeSendRepositoryTest - SafeSend entry persistence and expiration queries

Tests database interactions:

Entity save/update/delete
Query methods (findByEmail, findByToken)
Unique constraints validation
Cascade delete behavior
Transaction rollback scenarios

5. UI Tests (TestFX)

User Interface Tests with TestFX

# Run all UI tests
mvn test -Dtest=*ControllerTest

# Run specific controller test
mvn test -Dtest=LoginControllerTest
mvn test -Dtest=RegisterControllerTest
mvn test -Dtest=SettingsControllerTest

Test Files: 4 controller tests + 1 base class

LoginControllerTest (8 tests) - Login form validation, password toggle, authentication
RegisterControllerTest (11 tests) - Registration form, password strength indicator, password generator
SettingsControllerTest (16 tests) - Account deletion with confirmation phrase validation
SafeSendControllerTest (5 tests) - Secure sharing UI and expiration options
TestFXBaseTest - Base class with JavaFX test configuration

Total UI Tests: 40+ tests covering all major user workflows

UI Test Coverage:

Form validation (empty fields, invalid input)
Password visibility toggle (show/hide)
Password strength real-time feedback
Password generator functionality
Account deletion confirmation with exact phrase matching
Table data display and configuration
ComboBox default values and options
Read-only TextArea validation
Session management in UI
Error message display

TestFX Features:

Spring Boot integration with dependency injection
H2 in-memory database for isolated tests
WaitForAsyncUtils for JavaFX thread synchronization
Cleanup with @DirtiesContext after each test
Stable tests avoiding flaky behavior

6. Integration Tests

Full Workflow Integration Test

mvn test -Dtest=SafeCoreIntegrationTest

Tests complete end-to-end user workflow with real database:

User registration with password validation
Login authentication with session creation
Add encrypted password entry to vault
Retrieve and decrypt password entry
Update existing entry
Delete entry
Logout and session cleanup

Backup Integration Test

mvn test -Dtest=BackupIntegrationTest

Tests backup/restore functionality:

Export encrypted backup to .safe file
Import and decrypt backup file
Data integrity after restore
Key derivation for encryption

7. Exception Tests

Custom Exception Tests

mvn test -Dtest=*ExceptionTest

Test Files:

UserAlreadyExistsExceptionTest
UserNotFoundExceptionTest
WeakPasswordExceptionTest
ExpiredLinkExceptionTest
LinkNotFoundExceptionTest
InvalidTokenExceptionTest
SafeCoreExceptionTest

Tests exception handling:

Custom exception message construction
Exception hierarchy
Proper exception propagation
Error handling in UI layer

Test Configuration

Test Properties (src/test/resources/application-test.properties):

# H2 in-memory database
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driver-class-name=org.h2.Driver
spring.jpa.hibernate.ddl-auto=create-drop
spring.jpa.show-sql=false
spring.jpa.properties.hibernate.format_sql=false

# Test profile
spring.profiles.active=test

# Disable banner
spring.main.banner-mode=off

Test Reports

Generate Coverage Report:

mvn clean test jacoco:report

Report location: target/site/jacoco/index.html

Surefire Test Reports:

Location: target/surefire-reports/

XML reports for CI/CD integration
TXT reports with test execution details

Writing New Tests

Unit Test Template

@SpringBootTest
@ActiveProfiles("test")
class MyServiceTest {
    
    @Autowired
    private MyService myService;
    
    @MockBean
    private MyRepository myRepository;
    
    @Test
    void testMethodName_whenCondition_thenExpectedResult() {
        // Arrange
        when(myRepository.findById(1L)).thenReturn(Optional.of(entity));
        
        // Act
        Result result = myService.performOperation(1L);
        
        // Assert
        assertNotNull(result);
        assertEquals(expectedValue, result.getValue());
        verify(myRepository, times(1)).findById(1L);
    }
}

TestFX UI Test Template

@SpringBootTest
@ActiveProfiles("test")
@DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_EACH_TEST_METHOD)
class MyControllerTest extends TestFXBaseTest {
    
    @Autowired
    private ApplicationContext applicationContext;
    
    private void loadView() {
        runOnFxThread(() -> {
            try {
                FXMLLoader loader = new FXMLLoader(
                    getClass().getResource("/com/safecore/ui/view/my-view.fxml")
                );
                loader.setControllerFactory(applicationContext::getBean);
                Parent root = loader.load();
                stage.setScene(new Scene(root));
                stage.show();
            } catch (Exception e) {
                throw new RuntimeException("Failed to load view", e);
            }
        });
        WaitForAsyncUtils.waitForFxEvents();
    }
    
    @Test
    void testUIElement_whenAction_thenExpectedBehavior() {
        loadView();
        
        TextField myField = lookup("#myField").query();
        assertNotNull(myField);
        
        interact(() -> myField.setText("test"));
        WaitForAsyncUtils.waitForFxEvents();
        
        assertEquals("test", myField.getText());
    }
}

Test Best Practices

Isolation: Each test is independent and can run in any order
H2 Database: Tests use in-memory database, reset after each test
Mocking: External dependencies are mocked to focus on unit logic
Cleanup: @DirtiesContext ensures Spring context is recreated for UI tests
Assertions: Clear assertion messages for debugging failures
Naming: Tests follow methodName_whenCondition_thenExpectedResult convention
Coverage: Aim for 80%+ code coverage with meaningful tests
Performance: Performance tests validate acceptable execution times
UI Stability: TestFX tests avoid flaky behavior with proper synchronization

Continuous Integration

Tests are designed to run in CI/CD pipelines:

No external dependencies (except H2)
Headless JavaFX support for UI tests
Maven Surefire integration
JaCoCo coverage reports
Fast execution (full suite under 5 minutes)

API Documentation

Internal Service APIs

UserService

public interface UserService {
    /**
     * Registers a new user with email and password.
     * 
     * @param email User email (must be unique)
     * @param plainPassword Master password (minimum MEDIUM strength)
     * @return Immutable User domain object
     * @throws UserAlreadyExistsException if email already registered
     * @throws WeakPasswordException if password below minimum strength
     */
    User register(String email, String plainPassword);
    
    /**
     * Authenticates user with credentials.
     * 
     * @param email Registered email
     * @param plainPassword Plain text password
     * @return Optional<User> - present if credentials valid, empty otherwise
     */
    Optional<User> login(String email, String plainPassword);
}

VaultService

public class VaultService {
    /**
     * Adds encrypted password entry for current user.
     * 
     * @param service Service name (e.g., "Gmail")
     * @param username Username or email for service
     * @param plain Plain text password (will be encrypted)
     * @param expiry Optional expiration date (null for no expiry)
     */
    @Transactional
    public void addEntry(String service, String username, String plain, LocalDateTime expiry);
    
    /**
     * Retrieves all password entries for currently authenticated user.
     * 
     * @return List of PasswordEntryEntity with encrypted passwords
     */
    public List<PasswordEntryEntity> getEntriesForCurrentUser();
    
    /**
     * Decrypts password from encrypted byte array.
     * 
     * @param encrypted Encrypted password bytes (includes IV)
     * @return Decrypted plain text password
     */
    public String decryptPassword(byte[] encrypted);
    
    /**
     * Deletes password entry by ID.
     * 
     * @param id Entry UUID
     */
    @Transactional
    public void deleteEntry(UUID id);
    
    /**
     * Exports entire vault as encrypted JSON backup.
     * 
     * @param destinationFile Target .safe file
     * @throws Exception if encryption or file write fails
     */
    @Transactional(readOnly = true)
    public void exportVaultAsEncryptedJson(File destinationFile) throws Exception;
    
    /**
     * Imports vault entries from encrypted backup.
     * 
     * @param sourceFile Source .safe file
     * @throws Exception if decryption or parsing fails
     */
    @Transactional
    public void importVaultFromEncryptedJson(File sourceFile) throws Exception;
}

SecurityAuditService

public interface SecurityAuditService {
    /**
     * Analyzes vault for security weaknesses.
     * 
     * @return AuditResult with health score and vulnerability counts
     */
    AuditResult runAudit();
}

public record AuditResult(
    int score,           // Health score 0-100
    int weakCount,       // Number of weak passwords
    int oldCount,        // Number of passwords > 1 year old
    int reusedCount,     // Number of reused passwords
    int totalPasswords   // Total vault entries
) {}

PasswordGenerator

@Component
public class PasswordGenerator {
    /**
     * Generates cryptographically secure password.
     * 
     * @param length Desired length (minimum 12, recommended 16+)
     * @return Random password meeting STRONG criteria
     */
    public String generateSafe(int length);
}

PasswordStrengthEvaluator

@Component
public class PasswordStrengthEvaluator {
    /**
     * Evaluates password strength based on multiple criteria.
     * 
     * @param password Password to evaluate
     * @return Strength enum (WEAK, MEDIUM, STRONG)
     */
    public Strength evaluate(String password);
    
    public enum Strength {
        WEAK,    // < 8 chars OR < 3 criteria
        MEDIUM,  // >= 8 chars AND 3 criteria
        STRONG   // >= 8 chars AND all 4 criteria
    }
}

Encryption API

EncryptionStrategy

public interface EncryptionStrategy {
    /**
     * Encrypts plaintext string to byte array.
     * 
     * @param plaintext Data to encrypt
     * @return Encrypted bytes with prepended IV
     */
    byte[] encrypt(String plaintext);
    
    /**
     * Decrypts byte array to plaintext string.
     * 
     * @param ciphertext Encrypted bytes (includes IV)
     * @return Decrypted plaintext
     * @throws SecurityException if decryption fails
     */
    String decrypt(byte[] ciphertext);
}

AESEncryptionStrategy

@Component
public class AESEncryptionStrategy implements EncryptionStrategy {
    private static final String ALGORITHM = "AES/CBC/PKCS5Padding";
    
    @Override
    public byte[] encrypt(String plainText) {
        // 1. Generate random 128-bit IV
        // 2. Initialize Cipher with AES-256-CBC
        // 3. Encrypt plaintext
        // 4. Prepend IV to ciphertext
        // 5. Return combined byte array
    }
    
    @Override
    public String decrypt(byte[] cipherText) {
        // 1. Extract first 16 bytes as IV
        // 2. Extract remaining bytes as ciphertext
        // 3. Initialize Cipher with IV
        // 4. Decrypt ciphertext
        // 5. Return plaintext string
    }
}

Contributing

Contributions are welcome! Please follow these guidelines:

Development Setup

Fork the repository

Create feature branch:

git checkout -b feature/your-feature-name

Make changes with clear, atomic commits
Write/update tests for new functionality
Ensure all tests pass:
```
mvn test
```
Verify code quality:
```
mvn checkstyle:check
```

Code Style

Java: Follow Oracle Java Code Conventions
Indentation: 4 spaces (no tabs)
Line Length: Max 120 characters
Naming:
- Classes: PascalCase
- Methods/Variables: camelCase
- Constants: UPPER_SNAKE_CASE
JavaDoc: Required for public APIs

Commit Messages

Format: type(scope): description

Types:

feat: New feature
fix: Bug fix
docs: Documentation only
style: Code style (formatting, no logic change)
refactor: Code restructuring
test: Adding/updating tests
chore: Build process, dependencies

Example:

feat(vault): Add auto-expire password entries

- Implement scheduled cleanup job
- Add expiresAt column to PasswordEntryEntity
- Update UI to display expiration warnings

Pull Request Process

Update README.md with changes (if applicable)
Update CHANGELOG.md with new version
Ensure all tests pass and coverage maintained
Request review from maintainers
Address review feedback
Squash commits if requested
Maintainer merges after approval

Reporting Bugs

Use GitHub Issues with template:

**Describe the bug**
Clear description of what's wrong.

**To Reproduce**
1. Go to '...'
2. Click on '....'
3. See error

**Expected behavior**
What should have happened.

**Screenshots**
If applicable.

**Environment:**
- OS: [e.g., Windows 11, macOS Ventura]
- Java Version: [e.g., OpenJDK 17.0.5]
- SafeCore Version: [e.g., 1.0.0]

**Additional context**
Any other relevant information.

Suggesting Features

Use GitHub Issues with template:

**Feature Description**
Clear description of proposed feature.

**Use Case**
Why is this feature needed?

**Proposed Solution**
How should it work?

**Alternatives Considered**
Other approaches you've thought of.

**Additional Context**
Mockups, diagrams, related issues.

License

This project is licensed under the MIT License.

MIT License

Copyright (c) 2026 Dania Ciampalini, Cecilia Vignani

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Authors

Dania Ciampalini & Cecilia Vignani

This project was developed as part of a Software Engineering course, demonstrating enterprise-grade architecture, design patterns, and security best practices in a real-world password management application.

Acknowledgments

This project was built using outstanding open-source technologies:

Spring Framework Team: For Spring Boot 3.x, Spring Data JPA, and comprehensive dependency injection
OpenJFX Community: For JavaFX 17 and modern desktop UI capabilities
PostgreSQL Global Development Group: For robust, production-grade relational database
Neon: For serverless PostgreSQL hosting with excellent developer experience
jBCrypt Contributors: For robust BCrypt implementation
JUnit Team: For JUnit 5 testing framework
Mockito Contributors: For powerful mocking capabilities
PlantUML Project: For UML diagram generation
Maven Community: For reliable build and dependency management
JaCoCo Team: For comprehensive code coverage analysis

Special Thanks

OWASP: For security best practices and password storage guidelines
Material Design: For UI/UX design inspiration
GitHub: For hosting and collaboration tools

Educational Resources

Effective Java by Joshua Bloch
Design Patterns: Elements of Reusable Object-Oriented Software by Gang of Four
Spring in Action by Craig Walls

SafeCore - Enterprise-Grade Password Security

Built with security, quality, and engineering excellence in mind.

For support, please open an issue on GitHub.

Authors: Dania Ciampalini & Cecilia Vignani

GitHub: @DaniaCiampalini & @CeciliaVignani

Name		Name	Last commit message	Last commit date
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.idea		.idea
docs		docs
src		src
.gitignore		.gitignore
LICENSE		LICENSE
README.it.md		README.it.md
README.md		README.md
pom.xml		pom.xml

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SafeCore - Secure Password Manager

Table of Contents

Overview

Key Features

Security Features

Core Functionality

User Experience

Architecture

Layered Architecture (4-Tier)

Component Responsibilities

Technology Stack

Core Technologies

Security Libraries

Testing Frameworks

Build Tools

Project Structure

Design Patterns

1. Strategy Pattern (Encryption)

2. Repository Pattern (Data Access)

3. Builder Pattern (Domain Objects)

4. Observer Pattern (Vault Updates)

5. Singleton Pattern (Session Management)

6. Factory Pattern (Encryption Strategy Selection)

7. Dependency Injection (Spring Framework)

Security Architecture

Encryption Implementation

AES-256-CBC Encryption

BCrypt Password Hashing

Zero-Knowledge Architecture

Password Strength Evaluation

Security Audit System

Use Cases

UC-1: User Registration

UC-2: User Login

UC-3: Add Password Entry

UC-4: Security Audit

UC-5: Generate Secure Password

UC-6: Export Vault Backup

UC-7: Import Vault Backup

UC-8: SafeSend Secure Sharing

UC-9: SafeSend Access Secret

UC-10: Password Reset Request

UML Diagrams

Use Case Diagram

Sequence Diagrams

Registration Flow

Login Flow

Add Entry Flow

Security Audit Flow

Component Diagram

Package Diagram

Class Diagrams

Class Diagram - Complete System Architecture

Sequence Diagram - User Login Flow

Sequence Diagram - Add Password Entry

Sequence Diagram - Security Audit

Sequence Diagram - Export Vault Backup

Sequence Diagram - SafeSend Create Link

State Diagram - Password Entry Lifecycle

Component Diagram - System Architecture

Package Diagram

Installation

Prerequisites

Step 1: Clone Repository

Step 2: Build Project

Step 3: Run Application

Step 4: Verify Installation

Configuration

Database Configuration

Security Configuration

JavaFX UI Configuration

Usage

First-Time Setup

Managing Passwords

Add New Entry

Generate Secure Password