ngdp-crypto

Encryption and decryption support for Blizzard's NGDP/TACT system.

Installation

Add this to your Cargo.toml:

[dependencies]
ngdp-crypto = "0.3"

Overview

This crate provides cryptographic functionality for handling encrypted content in Blizzard's games. It implements the specific cipher configurations and key management required for TACT (Trusted Application Content Transfer) files.

Features

Salsa20 Stream Cipher: Modern encryption used in recent WoW versions
ARC4 (RC4) Cipher: Legacy encryption for older content
Key Management: Automatic loading and management of encryption keys
Multiple Key Sources: File-based, environment variables, and hardcoded keys
Format Support: CSV, TXT, and TSV key file formats

Usage

Basic Decryption

use ngdp_crypto::{KeyService, decrypt_salsa20};

// Initialize key service
let mut key_service = KeyService::new();
key_service.load_from_standard_dirs()?;

// Get a key by name
let key_name = 0xFA505078126ACB3E_u64;
if let Some(key) = key_service.get_key(key_name) {
    // Decrypt data
    let decrypted = decrypt_salsa20(encrypted_data, key, iv, block_index)?;
}

Key File Management

The KeyService automatically searches for key files in:

~/.config/cascette/
~/.tactkeys/
Path specified in CASCETTE_KEYS_PATH environment variable

Supported key file formats:

# CSV Format (WoW.txt style)
FA505078126ACB3E,BDC51862ABED79B2DE48C8E7E66C6200

# TXT Format with description
FA505078126ACB3E BDC51862ABED79B2DE48C8E7E66C6200 WoW 8.2.0.30898 Nazjatar Cinematic

# TSV Format
FA505078126ACB3E BDC51862ABED79B2DE48C8E7E66C6200

Cipher Details

Salsa20

Uses 16-byte keys extended to 32 bytes (by duplication)
4-byte IV extended to 8 bytes (by duplication)
Block index XORed with first 4 bytes of IV
Compatible with WoW's BLTE encryption

ARC4/RC4

Combines key (16 bytes) + IV (4 bytes) + block_index (4 bytes)
Padded to 32 bytes with zeros
Used for legacy content

Key Sources

The crate includes hardcoded keys for common WoW content and can load additional keys from:

TACTKeys Repository: Community-maintained key database
Local Files: User-provided key files
Built-in Keys: Common keys hardcoded in the library

Examples

Loading Keys from File

use ngdp_crypto::KeyService;
use std::path::Path;

let mut key_service = KeyService::new();
let keys_loaded = key_service.load_key_file(Path::new("/path/to/WoW.txt"))?;
println!("Loaded {} keys", keys_loaded);

Decrypting BLTE Blocks

use ngdp_crypto::{decrypt_salsa20, decrypt_arc4};

// For Salsa20 encrypted blocks
let decrypted = decrypt_salsa20(
    encrypted_data,
    key,
    iv,
    block_index
)?;

// For ARC4 encrypted blocks
let decrypted = decrypt_arc4(
    encrypted_data,
    key,
    iv,
    block_index
)?;

Performance

Zero-copy operations where possible
Efficient key lookups using HashMap
Minimal allocations during decryption

License

MIT OR Apache-2.0

ngdp-crypto 0.4.2