Player identity and username

CyberM gives every installation a durable cryptographic identity. The username shown in chat, nameplates, presence events, and server scripts belongs to that identity and is verified by the Master.

Stable id and display name#

Two identifiers have different jobs:

Always persist userId. A player can rename their profile and receives a new playerId after reconnecting.

Changing the username#

The server browser shows the current username in its Identity field. Pressing Save sends a freshly signed enrollment request to the Master. The Master accepts the update only when the private key already attached to the userId signed it.

Names contain 1 through 32 UTF-8 bytes and cannot contain control characters. A username cannot be changed during an active game session.

The private key never leaves the Windows identity store. The request, response, and saved profile contain no reusable password.

What a game server verifies#

The Master issues an Ed25519 certificate covering all three public profile values:

userId || P-256 public key || displayName

During connection, the game server verifies that certificate and a fresh P-256 session proof bound to its challenge. Changing only the name in a modified client invalidates the Master certificate, so the forged name is rejected before the session becomes active.

Server Lua#

Server resources receive the verified values through the normal player API:

AddEventHandler("playerJoining", function()
    local player = source
    print(GetPlayerIdentifier(player)) -- durable userId
    print(GetPlayerName(player))       -- Master-verified displayName
end)

The username-editing Lua bridge is reserved for the trusted local server-browser package. Downloaded server resources cannot rewrite a player's identity.