To deliver patches safely, sign each patch with a key kept off general build machines, verify the signature in the game before loading, fetch only from your own hosts over HTTPS, and log which patch loaded. Godot's documentation names the compromised launcher and the swapped file as real scenarios, and the same logic applies to any engine.
Where a patch can be tampered with
Follow the patch from your build to a player's memory. Each handoff is a place it could change.
| Stage | Risk | Control |
|---|---|---|
| Build machine | Someone alters the output or signs a bad build | Limited access; signing key not on every agent |
| Storage and CDN | A compromised account replaces the file | Strong login, few writers, audit of changes |
| Download | Interception or redirection | HTTPS from your own domains |
| Local disk | Malware swaps the file after download | Verify at load, not only at download |
| Launcher or loader | Launcher is compromised | Signature checked by the game itself, not only the launcher |
Godot's documentation describes three scenarios in this spirit: a mod with malicious code, malware on the end user's PC replacing the PCK, and a launcher used to distribute patches becoming compromised. It suggests asymmetric cryptography, with a public key in the main pack and patch packs signed by the private key. Unity's documentation separately offers a CRC-32 option when loading an AssetBundle from a file, which catches corruption and some tampering when the expected value comes from a trusted source.
The checklist
- Inventory patch types. Code patches, data packs, content bundles, config files. Treat code and script bearing packs as highest risk.
- Pick a signing method. A public key shipped inside the game build and a private key held by release engineers.
- Protect the private key. A hardware token or a managed key service, not a file on a shared server. Name who can use it.
- Sign in a controlled step. A release job with approvals, not a laptop.
- Verify in the game. Check the signature before loading anything from the pack. Refuse to load on failure and log it.
- Do not trust the checksum next to the file. If the number lives with the file, an attacker replaces both.
- Pin hosts. The game should only fetch patches from domains you control.
- Support rollback. Keep the previous good patch and a way to revert quickly.
- Log the patch ID. Include it in crash reports so support can see what a player was running.
- Rehearse a bad patch. Practise the response once: pull the patch, publish a replacement, tell players.
Limit what a patch can do
Even a signed patch can contain a mistake. The smaller the patch's power, the smaller the damage. Prefer data patches over code patches where you can. If a patch can load scripts, review it like code and test it before release. Our guide on Godot mod loading routes shows the same idea for mods.
What the checklist does not cover
It does not protect against a leaked signing key, which is why step 3 matters most. It also does not cover what the patch depends on. Libraries and plugins in the patch have their own supply chain.
Safeguard's SBOM and dependency scanning covers the packages and libraries your repositories declare, and you can try a free scan at gold.safeguard.sh/scan. Signing and distribution design stay with your release team.
Quick check
Is HTTPS enough to protect a patch?
It protects the download. A file can still be swapped on disk afterwards, so verify at load time.
Where should the public key live?
Godot's documentation suggests storing it in the main pack, so the shipped game can verify later packs.
What is the biggest single risk?
A leaked signing key, because it lets an attacker produce patches that pass verification.
Sources
- Godot documentation: Exporting packs, patches, and mods
- Unity Scripting API: AssetBundle.LoadFromFile
Last reviewed: 19 October 2026.
