42pak-generator - A modern, open-source pak file manager

[mrhasnam]

big appreciation

 

[semsemw]

42pak-generator
A modern, open-source pak file manager for the Metin2 private server community
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What is this?
42pak-generator replaces the legacy EIX/EPK archive format with a new .VPK format featuring:

• AES-256-GCM encryption - per-file authenticated encryption with unique nonces
• LZ4 / Zstandard / Brotli compression - choose the algorithm that fits your needs
• BLAKE3 content hashing - cryptographic integrity verification for every file
• HMAC-SHA256 - archive-level tamper detection
• Single-file format - no more .eix + .epk pairs
• PBKDF2-SHA512 key derivation - 200,000 iterations, no more hardcoded keys
• Filename obfuscation - optional path mangling to prevent enumeration

It comes with both a GUI (WebView2 desktop app with dark/light theme) and a full CLI tool (42pak-cli).

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VPK vs EIX/EPK Comparison

Feature	EIX/EPK (Legacy)	VPK (42pak)
Encryption	TEA / Panama / HybridCrypt	AES-256-GCM
Compression	LZO	LZ4 / Zstandard / Brotli
Integrity	CRC32	BLAKE3 + HMAC-SHA256
File format	Dual file (.eix + .epk)	Single file (.vpk)
Archive entries	512 max	Unlimited
Filename length	160 bytes	512 bytes (UTF-8)
Key derivation	Hardcoded keys	PBKDF2-SHA512 (200k iterations)
Tamper detection	None	HMAC-SHA256 whole-archive

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Screenshots
Dark Theme

Spoiler: Home

Spoiler: Convert

Spoiler: Manage Archives

Spoiler: Settings

Spoiler: Help

Light Theme

Spoiler: Home

Spoiler: Convert

Spoiler: Manage Archives

Spoiler: Settings

Spoiler: Help

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Features
GUI (Desktop App)

• Create VPK archives from directories with drag-and-drop
• Convert EIX/EPK to VPK (supports both 40250 and FliegeV3 variants)
• Browse, search, extract, and validate VPK archives
• Step-by-step creation wizard with real-time progress
• Dark and light themes
• Archive diff view (side-by-side comparison)
• Duplicate file detection across archives

CLI (42pak-cli)

42pak-cli pack <SOURCE_DIR> [--output <FILE>] [--compression <lz4|zstd|brotli|none>] [--level <N>] [--passphrase <PASS>]
42pak-cli unpack <ARCHIVE> <OUTPUT_DIR> [--passphrase <PASS>] [--filter <PATTERN>]
42pak-cli list <ARCHIVE> [--passphrase <PASS>] [--filter <PATTERN>] [--json]
42pak-cli info <ARCHIVE> [--passphrase <PASS>] [--json]
42pak-cli verify <ARCHIVE> [--passphrase <PASS>] [--filter <PATTERN>] [--json]
42pak-cli diff <ARCHIVE_A> <ARCHIVE_B> [--passphrase <PASS>] [--json]
42pak-cli migrate <LEGACY_ARCHIVE> [--output <FILE>] [--compression <TYPE>] [--passphrase <PASS>]
42pak-cli search <WORKSPACE_DIR> <FILENAME_OR_PATTERN>
42pak-cli check-duplicates <WORKSPACE_DIR> [--read-index]
42pak-cli watch <SOURCE_DIR> [--output <FILE>] [--debounce <MS>]

• -q / --quiet suppresses all output except errors
• --json outputs structured JSON for scripting
• Exit codes: 0 = success, 1 = error, 2 = integrity failure, 3 = wrong passphrase

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Metin2 Client Integration
Drop-in C++ integration files are provided for two reference source trees:

• 40250 / ClientVS22 - targets the multi-cipher HybridCrypt architecture (Camellia, Twofish, XTEA)
• FliegeV3 - targets the simpler XTEA/LZ4 architecture

Each profile includes:

• VpkLoader.h/cpp - drop-in CVpkPack class replacing CEterPack
• VpkCrypto.h/cpp - standalone crypto module (AES-GCM, BLAKE3, PBKDF2)
• EterPackManager_Vpk.h/cpp - patched manager with VPK + EPK fallback
• INTEGRATION_GUIDE.md - step-by-step instructions

Integration is just 2 changes:

1. Call SetVpkPassphrase() before the registration loop
2. Replace RegisterPack() with RegisterPackAuto()

VPK and EPK coexist - RegisterPackAuto checks for a .vpk file first and falls back to .eix/.epk if not found. You can convert packs incrementally.
Server integration is also included (optional CVpkHandler for reading configs/protos from VPK).

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VPK File Format
Single-file archive layout:

+-------------------------------------+
| VpkHeader (512 bytes, fixed)        |  Magic "42PK", version, entry count
+-------------------------------------+
| Data Block 0 (aligned to 4096)      |  Compressed + encrypted file data
+-------------------------------------+
| Data Block 1 (aligned to 4096)      |
+-------------------------------------+
| ...                                 |
+-------------------------------------+
| Entry Table (variable size)         |  If encrypted: AES-GCM wrapped
+-------------------------------------+
| HMAC-SHA256 (32 bytes)              |  Covers everything above
+-------------------------------------+

Encryption pipeline:
Original -> LZ4 Compress -> AES-256-GCM Encrypt -> Store
Key derivation:
PBKDF2-SHA512("42PK-v1:" + passphrase, salt, 100000 iter) -> 64 bytes
First 32 bytes = AES key, last 32 bytes = HMAC key.

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Download & Build
Prerequisites

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• Windows 10 version 1809+
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  (usually pre-installed)

Build from source

cd 42pak-generator
dotnet restore
dotnet build --configuration Release

Portable release

# CLI single-exe (~65 MB)
.\publish.ps1 -Target CLI
# GUI portable (~163 MB)
.\publish.ps1 -Target GUI
# Both + Inno Setup installer
.\publish.ps1 -Target All

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Technologies

• Runtime: .NET 8.0 (C# 12)
• UI: WebView2 + WinForms
• Frontend: HTML5, CSS3, Vanilla JS
• Encryption: AES-256-GCM (System.Security.Cryptography)
• Key Derivation: PBKDF2-SHA512 (200,000 iterations)
• Hashing: BLAKE3
• Compression: LZ4, Zstandard, Brotli
• C++ Crypto: OpenSSL 1.1+
• Testing: xUnit (22 tests)

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License
MIT License - free to use, modify, and distribute.
Source Code

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Contributions welcome! Open an issue or pull request on GitHub.

many thanks

 

[serhat1976]

sending love

 

[nagatto]

appreciate you always

 

[alpiepie31]

thank you so much