Sigil
Hardens Minecraft server access with cryptographic authentication and trust pinning.
About this Mod
Sigil is a security-focused Forge mod that adds cryptographic access control to Minecraft servers. Instead of relying solely on vanilla UUID checks, Sigil requires players to authenticate using server-signed Ed25519 certificates during login.
Sigil supports both online-mode servers (certificates bound to Mojang UUIDs) and offline-mode servers (certificates bound to cryptographic keypairs), allowing private, LAN, or invite-only servers to enforce strong identity guarantees.
Each server has a deterministic identity derived from its signing key, and clients pin the server fingerprint to prevent man-in-the-middle attacks or credential leakage. Certificates can be time-limited, revoked instantly, and distributed through ready-to-use admin bundles.
Sigil is designed for server operators who want explicit control over who may connect, without turning Minecraft into an account system or permissions mod.
For information on utilizing this mod please visit the main repository page
To report any bugs or issues please create an issue on the offical issues page
Sigil enforces access control - not anti-cheat or gameplay rules.
Available Versions
How to Install Sigil on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set forge Loader
In the panel under "Egg", select the forge loader and matching Minecraft version (1.20.1).
Install Mod
Open the mod browser in the dashboard and search for "Sigil". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.20.1
Server-side
✓ RequiredRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Sigil server crashes on startup – what to do?
Most common cause: wrong forge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.20.1). You can switch loaders with one click in the panel.
Is Sigil compatible with forge?
Sigil officially supports forge for Minecraft 1.20.1. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Sigil – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Sigil consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
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Rent Modded Server
Install Sigil with just one click on your server.