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Documentation

Everything you need to protect your 3D print files, manage licenses, and catch pirates.

Getting Started

Quick Start Guide

Encrypt your first file in under 2 minutes

Dashboard Overview

Navigate the designer dashboard

Desktop App Setup

Install and configure the unlock app

For Designers

Encrypting Files

Upload STL files and generate .stlx protected files

Token Management

Generate, distribute, and revoke purchase tokens

Bulk Operations

CSV import for batch token generation

Watchdog Scanner

Automated piracy detection across 9 platforms

DMCA Takedowns

Generate platform-specific takedown notices

Evidence Reports

Forensic evidence for legal action

For Buyers

Unlocking Files

How to unlock .stlx files with your token

Web Unlock

Unlock files in your browser — no app needed

Supported Slicers

OrcaSlicer, PrusaSlicer, Cura, Bambu Studio, and more

License Transfer

Transfer your license to a new device

Technical Reference

Encryption Spec

AES-256-GCM with per-product keys and HKDF-SHA256 derivation

.stlx File Format

Binary format specification for encrypted STL files

Watermark Methods

8 forensic watermarking techniques (4 mesh + 4 G-code)

API Reference

REST API endpoints for CLI and integrations

Webhook Events

Etsy order webhooks and event notifications

Integrations

Etsy Integration

Auto-generate tokens from Etsy orders

OctoPrint

Send unlocked files directly to your printer

Slicer Profiles

Upload and distribute slicer profiles with your files

Embeddable Widget

Add a storefront widget to your website

Quick Start

1

Create an account

Sign up free — no credit card required. You get 5 products and 50 tokens/month on the free plan.

2

Upload your STL file

Go to Products → Upload STL. Choose Standard mode (buyer uses their slicer) or Maximum mode (G-code only, raw mesh never exposed).

3

Generate a token for your buyer

Go to Tokens → Generate Token. Enter the buyer's email and select the product. Send them the SHLD-xxxx token with their purchase.

4

Buyer unlocks the file

Your buyer visits stlshield.com.au/unlock, enters their token and email, and downloads the STL. Or they can use the desktop app for offline access.

Encryption Specification

Every STL file is encrypted with a unique AES-256-GCM key derived via HKDF-SHA256. The encryption produces a .stlx file containing:

  • Magic bytes: STLSHLD\0
  • Version: UInt16 LE
  • Header length: UInt32 LE
  • JSON header: product ID, security mode, creation timestamp
  • Encrypted payload: AES-256-GCM ciphertext
  • Authentication tag: 16 bytes (GCM auth tag for tamper detection)

Keys are wrapped with a master key (AES-256-GCM) before storage. The master key is held in an environment variable and never written to disk or logs.

Forensic Watermarking

Every unlocked file is embedded with 8 redundant forensic watermarks — 4 on the mesh, 4 on G-code.

Mesh Watermarks

  • Vertex micro-perturbation (0.001-0.005mm)
  • Face reordering (deterministic shuffle)
  • Normal vector perturbation
  • Attribute byte steganography

G-code Watermarks

  • Feed rate LSB encoding
  • Coordinate LSB encoding
  • Extrusion LSB encoding
  • Comment marker steganography

Watermarks are keyed with HMAC-SHA256 using the buyer's email. They survive format conversion, re-meshing, and re-export — making leaked files traceable to the exact purchaser.

Supported Slicers

OrcaSlicer
PrusaSlicer
Cura
Bambu Studio
Slic3r
Simplify3D
IdeaMaker
FlashPrint
ChiTuBox

Standard mode works with all listed slicers. Maximum mode uses the built-in CuraEngine — the raw mesh never leaves memory.

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