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Published: Oct 25, 2023 License: MIT Imports: 17 Imported by: 24



Package login provides functions to decode and encode Minecraft login requests found in the Login packet connection request. The JWT chain found in this connection request may also be verified using this package.



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func Encode

func Encode(loginChain string, data ClientData, key *ecdsa.PrivateKey) []byte

Encode encodes a login request using the encoded login chain passed and the client data. The request's client data token is signed using the private key passed. It must be the same as the one used to get the login chain.

func EncodeOffline

func EncodeOffline(identityData IdentityData, data ClientData, key *ecdsa.PrivateKey) []byte

EncodeOffline creates a login request using the identity data and client data passed. The private key passed will be used to self sign the JWTs. Unlike Encode, EncodeOffline does not have a token signed by the Mojang key. It consists of only one JWT which holds the identity data of the player.

func MarshalPublicKey

func MarshalPublicKey(key *ecdsa.PublicKey) string

MarshalPublicKey marshals an ecdsa.PublicKey to a base64 encoded binary representation.

func Parse

func Parse(request []byte) (IdentityData, ClientData, AuthResult, error)

Parse parses and verifies the login request passed. The AuthResult returned holds the ecdsa.PublicKey that was parsed (which is used for encryption) and a bool specifying if the request was authenticated by XBOX Live. Parse returns IdentityData and ClientData, of which IdentityData cannot under any circumstance be edited by the client. Rather, it is obtained from an authentication endpoint. The ClientData can, however, be edited freely by the client.

func ParsePublicKey

func ParsePublicKey(b64Data string, key *ecdsa.PublicKey) error

ParsePublicKey parses an ecdsa.PublicKey from the base64 encoded public key data passed and sets it to a pointer. If parsing failed or if the public key was not of the type ECDSA, an error is returned.


type AuthResult

type AuthResult struct {
	PublicKey             *ecdsa.PublicKey
	XBOXLiveAuthenticated bool

AuthResult is returned by a call to Parse. It holds the ecdsa.PublicKey of the client and a bool that indicates if the player was logged in with XBOX Live.

type ClientData

type ClientData struct {
	// AnimatedImageData is a list of image data for animations. Each of the elements in this slice holds the
	// image data of a single frame of the animation.
	AnimatedImageData []SkinAnimation
	// CapeData is a base64 encoded string of cape data. This is usually an empty string, as skins typically
	// don't carry capes themselves.
	CapeData string
	// CapeID is an ID which, like the SkinID, identifies a skin. Usually this is either empty for no skin or
	// some ID containing a UUID in it.
	CapeID string `json:"CapeId"`
	// CapeImageHeight and CapeImageWidth are the dimensions of the cape's image.
	CapeImageHeight, CapeImageWidth int
	// CapeOnClassicSkin specifies if the cape that the player has equipped is part of a classic skin, which
	// usually points to one of the older MineCon capes.
	CapeOnClassicSkin bool
	// ClientRandomID is a random client ID number generated for the client. It usually remains consistent
	// through sessions and through game restarts.
	ClientRandomID int64 `json:"ClientRandomId"`
	// CurrentInputMode is the input mode used by the client. It is 1 for mobile and win10, but is different
	// for console input.
	CurrentInputMode int
	// DefaultInputMode is the default input mode used by the device.
	DefaultInputMode int
	// DeviceModel is a string indicating the device model used by the player. At the moment, it appears that
	// this name is always '(Standard system devices) System devices'.
	DeviceModel string
	// DeviceOS is a numerical ID indicating the OS of the device.
	DeviceOS protocol.DeviceOS
	// DeviceID is usually a UUID specific to the device. A different user will have the same UUID for this.
	// DeviceID is not guaranteed to always be a UUID. It is a base64 encoded string under some circumstances.
	DeviceID string `json:"DeviceId"`
	// GameVersion is the game version of the player that attempted to join, for example '1.11.0'.
	GameVersion string
	// GUIScale is the GUI scale of the player. It is by default 0, and is otherwise -1 or -2 for a smaller
	// GUI scale than usual.
	GUIScale int `json:"GuiScale"`
	// IsEditorMode is a value to dictate if the player is in editor mode.
	IsEditorMode bool
	// LanguageCode is the language code of the player. It looks like 'en_UK'. It follows the ISO language
	// codes, but hyphens ('-') are replaced with underscores. ('_')
	LanguageCode string
	// PersonaSkin specifies if the skin was a persona skin, meaning that it was created through the in-game
	// skin creator.
	PersonaSkin bool
	// PlatformOfflineID is either a UUID or an empty string ...
	PlatformOfflineID string `json:"PlatformOfflineId"`
	// PlatformOnlineID is either a uint64 or an empty string ...
	PlatformOnlineID string `json:"PlatformOnlineId"`
	// PlatformUserID holds a UUID which is only sent if the DeviceOS is of type device.XBOX. Its function
	// is not exactly clear.
	PlatformUserID string `json:"PlatformUserId,omitempty"`
	// PremiumSkin indicates if the skin the player held was a premium skin, meaning it was obtained through
	// payment.
	PremiumSkin bool
	// SelfSignedID is a UUID that remains consistent through restarts of the game and new game sessions.
	SelfSignedID string `json:"SelfSignedId"`
	// ServerAddress is the exact address the player used to join the server with. This may be either an
	// actual address, or a hostname. ServerAddress also has the port in it, in the shape of
	// 'address:port`.
	ServerAddress string
	// TODO: Find out what value SkinAnimationData holds and when it does hold something.
	SkinAnimationData string
	// SkinData is a base64 encoded byte slice of 64*32*4, 64*64*4 or 128*128*4 bytes. It is a RGBA ordered
	// byte representation of the skin colours.
	SkinData string
	// SkinGeometry is a base64 JSON encoded structure of the geometry data of a skin, containing properties
	// such as bones, uv, pivot etc.
	SkinGeometry string `json:"SkinGeometryData"`
	// SkinGeometryVersion is the version for SkinGeometry.
	SkinGeometryVersion string `json:"SkinGeometryDataEngineVersion"`
	// SkinID is a unique ID produced for the skin, for example 'c18e65aa-7b21-4637-9b63-8ad63622ef01_Alex'
	// for the default Alex skin.
	SkinID string `json:"SkinId"`
	// PlayFabID is the PlayFab ID produced for the player's skin. PlayFab is the company that hosts the
	// Marketplace, skins and other related features from the game. This ID is the ID of the skin used to
	// store the skin inside of PlayFab.
	PlayFabID string `json:"PlayFabId"`
	// SkinImageHeight and SkinImageWidth are the dimensions of the skin's image data.
	SkinImageHeight, SkinImageWidth int
	// SkinResourcePatch is a base64 encoded string which holds JSON data. The content of the JSON data points
	// to the assets that should be used to shape the skin. An example with a head animation can be found
	// below.
	// {
	//   "geometry" : {
	//      "animated_face" : "geometry.animated_face_persona_d1625e47f4c9399f_0_1",
	//      "default" : "geometry.persona_d1625e47f4c9399f_0_1"
	//   }
	// }
	// A skin resource patch must be present at all times. The minimum required data that the field must hold
	// is {"geometry": {"default": "geometry.persona_d1625e47f4c9399f_0_1"}}
	SkinResourcePatch string
	// SkinColour is a hex representation (including #) of the base colour of the skin. An example of the
	// colour sent here is '#b37b62'.
	SkinColour string `json:"SkinColor"`
	// ArmSize is the size of the arms of the player's model. This is either 'wide' (generally for male skins)
	// or 'slim' (generally for female skins).
	ArmSize string
	// PersonaPieces is a list of all persona pieces that the skin is composed of.
	PersonaPieces []PersonaPiece
	// PieceTintColours is a list of specific tint colours for (some of) the persona pieces found in the list
	// above.
	PieceTintColours []PersonaPieceTintColour `json:"PieceTintColors"`
	// ThirdPartyName is the username of the player. This username should not be used however. The DisplayName
	// sent in the IdentityData should be preferred over this.
	ThirdPartyName string
	// ThirdPartyNameOnly specifies if the user only has a third party name. It should always be assumed to be
	// false, because the third party name is not XBOX Live Auth protected, meaning it can be tempered with
	// and the username changed.
	// Although this field is obviously here for a reason, allowing this is too dangerous and should never be
	// done.
	ThirdPartyNameOnly bool
	// UIProfile is the UI profile used. For the 'Pocket' UI, this is 1. For the 'Classic' UI, this is 0.
	UIProfile int
	// TrustedSkin is a boolean indicating if the skin the client is using is trusted.
	TrustedSkin bool
	// OverrideSkin is a boolean that does not make sense to be here. The current usage of this field is unknown.
	OverrideSkin bool
	// CompatibleWithClientSideChunkGen is a boolean indicating if the client's hardware is capable of using the client
	// side chunk generation system.
	CompatibleWithClientSideChunkGen bool

ClientData is a container of client specific data of a Login packet. It holds data such as the skin of a player, but also its language code and device information.

func (ClientData) Validate

func (data ClientData) Validate() error

Validate validates the client data. It returns an error if any of the fields checked did not carry a valid value.

type IdentityData

type IdentityData struct {
	// XUID is the XBOX Live user ID of the player, which will remain consistent as long as the player is
	// logged in with the XBOX Live account. It is empty if the user is not logged into its XBL account.
	XUID string
	// Identity is the UUID of the player, which will also remain consistent for as long as the user is logged
	// into its XBOX Live account.
	Identity string `json:"identity"`
	// DisplayName is the username of the player, which may be changed by the user. It should for that reason
	// not be used as a key to store information.
	DisplayName string `json:"displayName"`
	// TitleID is a numerical ID present only if the user is logged into XBL. It holds the title ID (XBL
	// related) of the version that the player is on. Some of these IDs may be found below.
	// Win10: 896928775
	// Mobile: 1739947436
	// Nintendo: 2047319603
	// Note that these IDs are protected using XBOX Live, making the spoofing of this data very difficult.
	TitleID string `json:"titleId,omitempty"`

IdentityData contains identity data of the player logged in. It is found in one of the JWT claims signed by Mojang, and can thus be trusted.

func (IdentityData) Validate

func (data IdentityData) Validate() error

Validate validates the identity data. It returns an error if any data contained in the IdentityData is invalid.

type PersonaPiece

type PersonaPiece struct {
	// Default specifies if the piece is one of the default pieces. This is true when the piece is one of
	// those that a Steve or Alex skin have.
	Default bool `json:"IsDefault"`
	// PackID is a UUID that identifies the pack that the persona piece belongs to.
	PackID string `json:"PackId"`
	// PieceId is a UUID that identifies the piece itself, which is unique for each separate piece.
	PieceID string `json:"PieceId"`
	// PieceType holds the type of the piece. Several types I was able to find immediately are listed below.
	// - persona_skeleton
	// - persona_body
	// - persona_skin
	// - persona_bottom
	// - persona_feet
	// - persona_top
	// - persona_mouth
	// - persona_hair
	// - persona_eyes
	// - persona_facial_hair
	PieceType string
	// ProductID is a UUID that identifies the piece when it comes to purchases. It is empty for pieces that
	// have the 'IsDefault' field set to true.
	ProductID string `json:"ProductId"`

PersonaPiece represents a piece of a persona skin. All pieces are sent separately.

type PersonaPieceTintColour

type PersonaPieceTintColour struct {
	// Colours is an array of four colours written in hex notation (note, that unlike the SkinColor field in
	// the ClientData struct, this is actually ARGB, not just RGB).
	// The colours refer to different parts of the skin piece. The 'persona_eyes' may have the following
	// colours: ["#ffa12722","#ff2f1f0f","#ff3aafd9","#0"]
	// The first hex colour represents the tint colour of the iris, the second hex colour represents the
	// eyebrows and the third represents the sclera. The fourth is #0 because there are only 3 parts of the
	// persona_eyes skin piece.
	Colours [4]string `json:"Colors"`
	// PieceType is the type of the persona skin piece that this tint colour concerns. The piece type must
	// always be present in the persona pieces list, but not each piece type has a tint colour sent.
	// Pieces that do have a tint colour that I was able to find immediately are listed below.
	// - persona_mouth
	// - persona_eyes
	// - persona_hair
	PieceType string

PersonaPieceTintColour describes the tint colours of a specific piece of a persona skin.

type SkinAnimation

type SkinAnimation struct {
	// Frames is the amount of frames of the animation. The number of Frames here specifies how many
	// frames may be found in the Image data.
	Frames float64
	// Image is a base64 encoded byte slice of ImageWidth * ImageHeight bytes. It is an RGBA ordered byte
	// representation of the animation image pixels. The ImageData contains FrameCount images in it, which
	// each represent one stage of the animation. The actual part of the skin that this field holds
	// depends on the Type, where SkinAnimationHead holds only the head and its hat, whereas the other
	// animations hold the entire body of the skin.
	Image string
	// ImageHeight and ImageWidth are the dimensions of the animated image. Note that the size of this
	// image is not always 32/64/128.
	ImageHeight, ImageWidth int
	// Type is the type of the animation, which defines what part of the body the Image data holds. It is
	// one of the following:
	// 0 -> 'None', doesn't typically occur.
	// 1 -> Face animation.
	// 2 -> 32x32 Body animation.
	// 3 -> 128x128 Body animation.
	Type int
	// ExpressionType is the type of expression made by the skin, which is one of the following:
	// 0 -> Linear.
	// 1 -> Blinking.
	AnimationExpression int

SkinAnimation is an animation that may be present. It is applied on top of the skin default and is cycled through client-side.

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