authserverVerify

SessionGuard Client

Client-side companion for the SessionGuard server security protocol.

What does this mod do?

SessionGuard Client is a lightweight companion required to play on servers running the SessionGuard security protocol.

When you join a protected server, it sends you a cryptographic challenge. This mod responds by forwarding your official Minecraft access token back to the server — nothing more. The server then contacts Mojang's session API directly to verify you are the legitimate owner of your account.

Your credentials never leave the Minecraft session system. This mod does not make any HTTP requests, does not store any data, and does not modify gameplay in any way.

Why is this needed?

Servers running in offline mode cannot natively verify whether a player actually owns the Minecraft account they claim. SessionGuard solves this by implementing Mojang's official session verification protocol server-side. This mod is the client piece that makes the handshake possible.

Features

• Zero Mojang API calls client-side
• No data stored locally
• No gameplay changes
• No GUI, no commands, no configuration

Requirements

• Minecraft 1.20.1 — Fabric
• Fabric API
• Official Minecraft launcher (required for session verification to succeed)

Developed for the CRETANIA private server network.