Overview

A minimal command-line utility for safely transferring large files and datasets across air-gap boundaries using removable media.

Features

  • Air-gap ready - Designed for systems with no network access

  • Chunked transfers - Split large datasets across multiple USB drives

  • Integrity verification - SHA-256 checksums for all transfers

  • Resume capability - Continue interrupted transfers

  • Cross-platform - macOS, Windows, and Linux support

  • Lightweight - Pure Rust, single binary

How It Works

Transfer large datasets that exceed single USB drive capacity:

  • Pack: Split source files into chunks that fit on available USB drives

  • Transfer: Move USB drives across air-gap boundary

  • Unpack: Reconstruct original files on destination machine with verification

All operations maintain data integrity through cryptographic checksums.

Quick Start

Prerequisites

  • Rust toolchain (for building from source)

  • USB drives with sufficient combined capacity

  • Write access to source and destination directories

Installation

Build from source with Cargo, or use a pre-built binary for your platform.

First Transfer

# On source machine (connected side):
airgap-transfer pack ~/large-dataset /media/usb-drive --chunk-size 16GB

# Physically transfer USB drive(s) across air-gap

# On destination machine (air-gapped side):
airgap-transfer unpack /media/usb-drive ~/restored-dataset

Usage

Pack Operation

Split source files into chunks:

airgap-transfer pack <source> <usb-mount> [options]

Options:

  • --chunk-size <SIZE> - Maximum chunk size (default: auto-detect USB capacity)

  • --dry-run - Preview operations without writing

  • --no-verify - Skip checksum generation (checksums are generated by default)

Unpack Operation

Reconstruct files from chunks:

airgap-transfer unpack <chunk-location> <destination> [options]

Options:

  • --no-verify - Skip checksum verification (verification is enabled by default)

  • --keep-chunks - Don’t delete chunks after successful reconstruction (see FR-TRANSFER-014)

List Operation

Analyze chunk status:

airgap-transfer list <chunk-location>

Shows chunk inventory, sizes, and verification status.

Building

Requires Rust toolchain and platform-specific build tools.

See Roadmap for complete build instructions and architecture details.

Air-Gapped Deployment

AirGap Transfer supports deployment on systems with no internet access. All dependencies can be vendored and transferred offline via USB.

For detailed air-gap deployment procedures, see the AirGap Deploy project documentation.

Use Cases

  • Transfer large datasets (hundreds of GB) across air-gap boundaries

  • Backup critical data to removable media with verification

  • Deploy software and models to isolated systems

  • Migrate data between air-gapped environments

Privacy

AirGap Transfer is private by architecture:

  • Zero network code in the application

  • No analytics, telemetry, or external API calls

  • All data stays on local or removable media

  • Cryptographic verification ensures integrity

Why AirGap Transfer?

AirGap Transfer is the only lightweight, open-source, manifest-driven chunking tool designed specifically for multi-USB air-gap transfers. It fills the gap between manual processes and heavy enterprise solutions.

vs manual processes (tar + split, manual copying):

  • ✅ Automated chunking: No manual calculation of chunk sizes

  • ✅ Manifest tracking: JSON metadata tracks all chunks and verification status

  • ✅ Guaranteed integrity: SHA-256 checksums enforced, not optional

  • ✅ Resume capability: Continue interrupted transfers without starting over

  • ✅ No human error: Automated verification prevents forgotten checksums or lost chunks

vs rsync (rsync):

  • ✅ Multi-USB orchestration: Automatic chunking for drives that don’t fit data

  • ✅ Air-gap workflow: Designed for USB-to-USB transfer, not network/mounted filesystems

  • ✅ Manifest system: Track chunks across multiple drives

  • ✅ Complementary tool: Use rsync for local USB writes, AirGap Transfer for multi-drive orchestration

vs enterprise backup solutions (Commvault, Veeam, HCL BigFix):

  • ✅ Free and open source: No licensing costs

  • ✅ Lightweight: Single Rust binary, no infrastructure required

  • ✅ General-purpose: Not tied to backup/recovery or patch management workflows

  • ✅ Simple CLI: pack/unpack/list commands, nothing more

vs hardware solutions (data diodes, Owl Defense):

  • ✅ Software-only: No expensive hardware required

  • ✅ Bidirectional: Transfer data both ways (hardware diodes are one-way only)

  • ✅ Cost-effective: Free vs thousands/millions for hardware solutions

  • ✅ Flexible: Works with any USB storage, any platform

Unique value proposition: Automated orchestration for the “sneaker net” workflow. Provides enterprise-grade verification and resume capability without enterprise complexity or cost.

Use case: When you need to move 20GB+ across an air-gap and it won’t fit on a single USB drive, AirGap Transfer handles chunking, verification, and reconstruction automatically.

Platform Support

Platform

Support

Notes

macOS

Full

Tested on macOS 10.15+

Linux

Full

Tested on Ubuntu, Fedora, Debian

Windows

Full

Tested on Windows 10/11

Documentation

This README covers installation and usage. For development and technical specifications, see the documents below.

Start Here

Document

Purpose

Principles

Core design principles (read first)

Roadmap

Project status and direction

Technical Documentation

Document

Purpose

Software Requirements

Detailed functional requirements

Software Design

Architecture, data structures, component design

Test Plan

Test cases and procedures

Project Planning

Document

Purpose

Roadmap

MVP implementation milestones

Use Case Analysis

Workflow documentation