OffCrypt Desktop - Professional Windows Encryption Suite

OffCrypt Desktop is a professional Windows encryption application providing secure text and file encryption using cutting-edge cryptographic algorithms. Features both password-based encryption (ECDH+HKDF+AES-GCM) and X25519 public-key cryptography with NIST 2024 compliance for maximum security.

🔐 Fully Offline • 🔑 PGP-Style Keys • ⏰ Disappearing Messages • 📁 File Encryption • 🛡️ Zero Data Collection

⚡ Quick Start

System Requirements

• OS: Windows 10 version 1809 or later
• Framework: .NET 6.0 or later
• Architecture: x64, ARM64
• RAM: 512 MB minimum, 1 GB recommended

Installation

1. Download the latest release from GitHub Releases
2. Extract the .exe file to your preferred location
3. Run OffCryptDesktop.exe as administrator (first time only)
4. Set your master password in Tab 1

First Steps

1. Password Mode: Set master password → Type message → Click "Encrypt"
2. Public Key Mode: Generate X25519 keys → Share public key → Import recipient's key
3. File Encryption: Create encrypted .enc or .pgp files for secure storage

🔐 Key Features

Modern Cryptography

• ECDH + HKDF + AES-GCM: NIST 2024 compliant password-based encryption
• X25519 + AES-GCM: Next-generation public key cryptography
• Multiple ECDH Curves: P-256, P-384, P-521, and ephemeral keys
• Perfect Forward Secrecy: Session-based key derivation

Advanced Security

• Disappearing Messages: Time-limited secure communication (hours/days/weeks/months)
• PGP-Style Identity Management: Contact trust levels and fingerprint verification
• Memory Protection: Secure data handling with automatic cleanup
• Windows DPAPI Integration: OS-level private key protection

Professional Features

• File Operations: Create encrypted .enc and .pgp files
• Offline-First Design: No internet connection required or used
• Attack Protection: Constant-time operations, replay prevention
• Complete Data Wipe: Nuclear option for secure data removal

📱 Screenshots

Main Interface

Windows encryption software main dashboard showing ECDH+HKDF+AES-GCM configuration and secure messaging interface

Password-Based Encryption

Password-based encryption mode with disappearing messages settings and AES-256-GCM security options

X25519 Public Key Mode

X25519 public key cryptography interface for PGP-style secure communication without servers

📖 Documentation

• Complete User Manual - Comprehensive guide with step-by-step instructions
• How to Use - Quick reference for common operations
• Security Best Practices - Guidelines for secure usage
• Troubleshooting - Common issues and solutions

🛡️ Security & Standards

Cryptographic Compliance

• NIST SP 800-56A Rev. 3: Key establishment standards
• RFC 5869: HKDF implementation
• RFC 7748: X25519 elliptic curve
• FIPS 140-2: Validated cryptographic modules

Privacy & Security

• Zero Data Collection: No telemetry, analytics, or user data stored
• Open Source: GPL-3.0 license for full transparency
• Memory Safety: Secure handling of passwords and private keys
• Offline Operation: No network communication, fully air-gapped

🔧 Technical Specifications

Encryption Algorithms

Mode	Algorithm	Key Size	Authentication
Password	ECDH+HKDF+AES-GCM	256-bit	Built-in GCM
Public Key	X25519+AES-GCM	256-bit	Built-in GCM
Legacy Support	PBKDF2+AES-CBC	256-bit	HMAC-SHA256

Platform Integration

• Windows DPAPI: Secure private key storage
• Windows Forms/WPF: Native Windows UI framework
• Windows Cryptography API: OS-provided secure random generation
• .NET 6.0+: Modern runtime with security enhancements

🚀 Development

Technology Stack

• Language: C# (.NET 9.0+)
• UI Framework: Windows Forms
• Cryptography: Windows Cryptography API, Bouncy Castle
• Storage: Windows DPAPI, Registry, INI files

Building from Source

git clone https://github.com/EmptyCode0x86/OffCryptDesktop
cd OffCryptDesktop
dotnet restore
dotnet build --configuration Release

Project Structure

OffCryptDesktop/
├── Core/              # Cryptographic implementations
├── UI/                # Windows Forms interface
├── Security/          # Memory management & key storage
├── FileOperations/    # Encrypted file handling
└── Documentation/     # User guides and technical docs

💝 Support & Community

Get Help

• 📚 Documentation: User Manual
• 🐛 Issues: GitHub Issues
• 🐦 Updates: @OffCryptAndroid

Support Development

If you find OffCrypt Desktop useful, consider supporting the project:

Contributing

Contributions are welcome! Please read our contributing guidelines and ensure all security-related changes are thoroughly reviewed.

📄 License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.

Third-Party Acknowledgments

• Bouncy Castle: Cryptographic library
• Microsoft .NET: Runtime framework
• Windows Cryptography API: Secure random generation and key storage

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⚠️ Security Notice: This software is provided as-is for educational and legitimate security purposes. Users are responsible for compliance with local laws and regulations regarding encryption software.

🔐 OffCrypt Desktop - Secure communication without compromise

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Made by EmptyCode0x86 | Follow updates: @OffCryptAndroid