Sigil

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.