# Hytale Client Binary Analysis

CSC_LINK="/Users/sanasol/Downloads/Certificates-hytale.p12" CSC_KEY_PASSWORD="YieocpBVP68Rih*" APPLE_ID="sanasol2008rs@gmail.com" APPLE_APP_SPECIFIC_PASSWORD="ihah-lbta-movj-iqni" APPLE_TEAM_ID="9WVL8YG95H" npm run build:mac
CSC_LINK="/Users/sanasol/Downloads/Certificates-hytale.p12" CSC_KEY_PASSWORD="YieocpBVP68Rih*" APPLE_ID="sanasol2008rs@gmail.com" APPLE_APP_SPECIFIC_PASSWORD="ihah-lbta-movj-iqni" APPLE_TEAM_ID="9WVL8YG95H" npx electron-builder --mac --arm64


password ihah-lbta-movj-iqni
team id 9WVL8YG95H
cert pass YieocpBVP68Rih*

## Overview

This document contains a comprehensive analysis of the HytaleClient binary, documenting all discovered URLs, API endpoints, service domains, patchable strings, and internal functionality.

**Binary Analyzed:** `HytaleClient` (macOS .NET AOT compiled)
**Analysis Date:** 2026-01-27
**String Encoding:** UTF-16LE (Windows .NET string format)

---

## Table of Contents

1. [Service URLs](#1-service-urls)
2. [API Endpoints](#2-api-endpoints)
3. [World Tools & Builder Tools](#3-world-tools--builder-tools)
4. [External Service URLs](#4-external-service-urls)
5. [Patchable Strings](#5-patchable-strings)
6. [Sentry Error Tracking](#6-sentry-error-tracking)
7. [Internal Class References](#7-internal-class-references)
8. [Binary Offsets Reference](#8-binary-offsets-reference)
9. [Implementation Notes](#9-implementation-notes)

---

## 1. Service URLs

### 1.1 Primary Hytale Services

The client connects to four main service subdomains:

| Service | URL Pattern | Purpose | Status |
|---------|-------------|---------|--------|
| **Sessions** | `https://sessions.{domain}` | Authentication, JWT tokens, session management | Implemented in auth-server |
| **Account Data** | `https://account-data.{domain}` | Player profiles, skins, account information | Implemented in auth-server |
| **Telemetry** | `https://telemetry.{domain}` | Analytics, error reporting, usage statistics | Implemented (accepts/discards) |
| **Tools** | `https://tools.{domain}` | Asset editor, prefab management, world tools | **Not implemented** |

### 1.2 URL Construction

The client constructs URLs by combining:
1. Protocol: `https://`
2. Subdomain: `sessions.`, `account-data.`, `telemetry.`, `tools.`
3. Base domain: `hytale.com`

**Example:** `https://` + `sessions.` + `hytale.com` = `https://sessions.hytale.com`

The client patcher replaces these components to redirect traffic to the F2P auth server.

### 1.3 F2P Domain Routing

For F2P mode, all subdomains route to a single endpoint:
- `sessions.{f2p_domain}` → `https://{f2p_domain}`
- `account-data.{f2p_domain}` → `https://{f2p_domain}`
- `telemetry.{f2p_domain}` → `https://{f2p_domain}`
- `tools.{f2p_domain}` → `https://{f2p_domain}`

---

## 2. API Endpoints

### 2.1 Session Management Endpoints

#### POST /game-session/new
Create a new game session.

**Request:**
```json
{
  "clientVersion": "string",
  "platform": "string"
}
```

**Response:**
```json
{
  "token": "JWT token",
  "refreshToken": "refresh token",
  "expiresIn": 36000
}
```

#### POST /game-session/refresh
Refresh an existing session token.

**Request:**
```json
{
  "refreshToken": "string"
}
```

**Response:**
```json
{
  "token": "new JWT token",
  "refreshToken": "new refresh token",
  "expiresIn": 36000
}
```

#### POST /game-session/child
Create a child session (for server connections).

**Request:**
```json
{
  "parentToken": "string",
  "audience": "server identifier"
}
```

#### DELETE /game-session
Notify server of session end (player disconnect).

### 2.2 Server Join Endpoints

#### POST /server-join/auth-grant
Request authorization grant for connecting to a game server.

**Request:**
```json
{
  "serverAddress": "string",
  "serverPort": number
}
```

**Response:**
```json
{
  "grant": "authorization grant string"
}
```

#### POST /server-join/auth-token
Exchange authorization grant for server-specific token with certificate binding.

**Request:**
```json
{
  "grant": "authorization grant",
  "clientCertHash": "SHA256 hash of client certificate"
}
```

**Response:**
```json
{
  "token": "server-specific JWT with cnf claim"
}
```

### 2.3 Account Endpoints

#### GET /my-account/game-profile
Get the player's game profile.

**Response:**
```json
{
  "uuid": "player UUID",
  "username": "display name",
  "createdAt": "timestamp"
}
```

#### POST /my-account/game-profile
Update the player's game profile.

**Request:**
```json
{
  "username": "new display name"
}
```

#### GET /my-account/cosmetics
Get list of unlocked cosmetics for the player.

**Response:**
```json
{
  "cosmetics": [
    {
      "id": "cosmetic_id",
      "category": "category_name",
      "unlockedAt": "timestamp"
    }
  ]
}
```

#### POST /my-account/skin
Save player's skin/character customization preferences.

**Request:**
```json
{
  "skinTone": "SkinTone_01",
  "bodyType": "Default",
  "parts": {
    "haircut": "Haircut_ShortMessy.Blue",
    "eyes": "Eyes_Default.Green",
    "eyebrows": "Eyebrows_Default",
    "face": "Face_Default"
  }
}
```

### 2.4 JWKS Endpoint

#### GET /.well-known/jwks.json
Get JSON Web Key Set for JWT verification.

**Response:**
```json
{
  "keys": [
    {
      "kty": "OKP",
      "crv": "Ed25519",
      "x": "base64url-encoded-public-key",
      "kid": "key-id",
      "use": "sig",
      "alg": "EdDSA"
    }
  ]
}
```

### 2.5 Profile Lookup Endpoints

#### GET /profile/uuid/{uuid}
Lookup player profile by UUID.

#### GET /profile/username/{username}
Lookup player profile by username (server-scoped).

---

## 3. World Tools & Builder Tools

### 3.1 World Tools (worldtools.*)

These are in-game tools for world creation and editing in builder/creative mode.

| Tool | Command | Description |
|------|---------|-------------|
| **Change Model** | `worldtools.changeModel` | Change the model of an entity in the world |
| **Import Image** | `worldtools.importImage` | Import image files into the world as textures |
| **Import OBJ** | `worldtools.importObj` | Import 3D OBJ model files into the world |
| **Instance** | `worldtools.instance` | Manage world instances and copies |
| **Play Sound** | `worldtools.playSound` | Play sound effects in the world |
| **Prefab Editor** | `worldtools.prefabEditor` | Open the prefab editor interface |
| **Prefab List** | `worldtools.prefabList` | List and manage saved prefabs |
| **Spawn Entity** | `worldtools.spawnEntity` | Spawn entities at specified locations |
| **Spawn Particle** | `worldtools.spawnParticle` | Spawn particle effects |
| **Tint Chunk** | `worldtools.tintChunk` | Apply color tinting to world chunks |

### 3.2 Builder Tools (buildertools.*)

Additional tools for the asset editor and builder mode.

| Tool | Class | Description |
|------|-------|-------------|
| **Image Import** | `buildertools.imageimport.ImageImportPage` | UI page for importing images |
| **OBJ Import** | `buildertools.objimport.ObjImportPage` | UI page for importing OBJ models |
| **Prefab Editor** | `buildertools.prefabeditor.ui.PrefabEditorLoadSettings` | Prefab editor with load/save |
| **Prefab List** | `buildertools.prefablist.PrefabPage` | Prefab listing and management |

### 3.3 Machinima Tool

- **Purpose:** In-game cinematic/video recording tool
- **Access:** Available via hotbar slot
- **Message:** "Hotbar is full. Clear a slot to receive the Machinima tool."

### 3.4 Asset Editor

The client includes an asset editor with these features:
- `AssetEditorDownload` - Download assets from tools service
- `assetEditor.exportModal` - Export modal for assets
- `assetEditor.fileSaveState` - File save state management
- `assetEditor.property.tooltip` - Property tooltips

### 3.5 tools.hytale.com API Requirements

To fully support builder mode, the tools service would need:

```
POST /assets/upload
  - Upload asset files (images, models, sounds)
  - Returns asset ID/URL

GET /assets/{assetId}
  - Download asset by ID
  - Returns asset binary data

POST /prefabs/save
  - Save prefab definition
  - Returns prefab ID

GET /prefabs/{prefabId}
  - Load prefab by ID
  - Returns prefab JSON

GET /prefabs/list
  - List user's saved prefabs
  - Returns array of prefab metadata

DELETE /prefabs/{prefabId}
  - Delete a prefab
```

**Note:** The game functions without tools.hytale.com - it's only needed for cloud-based asset sharing in builder mode.

---

## 4. External Service URLs

### 4.1 Hytale Official URLs

| URL | Purpose | Patchable |
|-----|---------|-----------|
| `https://store.hytale.com/?upgrade=` | In-game store for purchases | Yes |
| `https://hytale.com/help/joining-friends` | Help documentation | Yes |
| `https://discord.gg/hytale` | Official Discord invite | Yes |

### 4.2 Third-Party Service URLs

| URL | Purpose | Notes |
|-----|---------|-------|
| `https://blockbench.net/downloads` | Blockbench download page | 3D model editor |
| `https://blockbench.net/plugins/hytale_plugin` | Hytale Blockbench plugin | For asset creation |
| `https://docs.sentry.io/platforms/dotnet/*` | Sentry documentation | Error tracking docs |
| `https://aka.ms/*` | Microsoft .NET documentation | Runtime docs |
| `https://learn.microsoft.com/*` | Microsoft Learn | .NET API docs |
| `https://go.microsoft.com/*` | Microsoft redirects | Various docs |

### 4.3 Graphics/Rendering References

| URL | Purpose |
|-----|---------|
| `https://www.khronos.org/opengl/wiki/Interface_Block_(GLSL)` | GLSL interface blocks |
| `https://www.khronos.org/opengl/wiki/Sampler_(GLSL)` | GLSL texture samplers |
| `https://www.shadertoy.com/view/Xd23Dh` | Shader reference |
| `https://www.shadertoy.com/view/ltlSRj` | Shader reference |
| `https://aras-p.info/texts/CompactNormalStorage.html` | Normal map compression |
| `https://mynameismjp.wordpress.com/2009/03/10/reconstructing-position-from-depth/` | Depth reconstruction |
| `https://briansharpe.files.wordpress.com/2018/07/moment-transparency-supp-av.pdf` | Transparency rendering |
| `https://www.pmavridis.com/research/fbcompression/` | Frame buffer compression |
| `https://jcgt.org/published/0002/02/09/` | Graphics technique |
| `https://jcgt.org/published/0006/01/03/` | Graphics technique |
| `https://graphics.cs.williams.edu/papers/CSSM/` | Graphics paper |
| `http://www.humus.name/Articles/Persson_LowLevelThinking.pdf` | Low-level graphics |

### 4.4 GitHub References

| URL | Purpose |
|-----|---------|
| `https://github.com/NLog/NLog.git` | Logging framework |
| `https://github.com/Noesis/Managed/tree/master/Src/Noesis/Core` | NoesisGUI core |
| `https://github.com/Noesis/Managed/tree/master/Src/NoesisApp/Core` | NoesisGUI app |
| `https://github.com/dotnet/dotnet` | .NET runtime |
| `https://github.com/ektrah/nsec.git` | NSec cryptography |
| `https://github.com/getsentry/sentry-dotnet` | Sentry .NET SDK |

---

## 5. Patchable Strings

### 5.1 Domain Strings

| Original | Replacement | Purpose |
|----------|-------------|---------|
| `hytale.com` | `{f2p_domain}` | Base domain (4-16 chars) |
| `sessions.` | Stripped or replaced | Session service subdomain |
| `account-data.` | Stripped or replaced | Account service subdomain |
| `telemetry.` | Stripped or replaced | Telemetry subdomain |
| `tools.` | Stripped or replaced | Tools service subdomain |

### 5.2 URL Strings

| Original | Can Replace With | Notes |
|----------|------------------|-------|
| `https://store.hytale.com/?upgrade=` | Custom store URL | In-game purchases |
| `https://discord.gg/hytale` | Custom Discord | Community link |
| `https://hytale.com/help/joining-friends` | Custom help docs | Help system |
| `sentry.hytale.com` | Own Sentry or disable | Error tracking |

### 5.3 String Encoding Details

**.NET UTF-16LE Format:**
- Each character is 2 bytes (little-endian)
- Example: "hytale" = `68 00 79 00 74 00 61 00 6c 00 65 00`
- Strings are length-prefixed in the binary

**Length Prefix Format:**
- 1 byte for strings < 128 chars
- 2 bytes (varint) for longer strings
- Followed by UTF-16LE character data

### 5.4 Current Patcher Behavior

The `clientPatcher.js` patches:
1. `sessions.hytale.com` → `{f2p_domain}` (single endpoint)
2. `account-data.hytale.com` → `{f2p_domain}`
3. `telemetry.hytale.com` → `{f2p_domain}`

**Not currently patched:**
- `tools.hytale.com` (builder mode assets)
- `store.hytale.com` (in-game store)
- `sentry.hytale.com` (error tracking)

---

## 6. Sentry Error Tracking

### 6.1 Sentry Configuration

**DSN Found in Binary:**
```
https://ca900df42fcf57d4dd8401a86ddd7da2@sentry.hytale.com/
```

**DSN Components:**
- Protocol: `https`
- Public Key: `ca900df42fcf57d4dd8401a86ddd7da2`
- Host: `sentry.hytale.com`
- Project ID: (after trailing slash)

### 6.2 Sentry Integration

The client uses the official Sentry .NET SDK:
- Package: `sentry-dotnet`
- Documentation refs found in binary

### 6.3 Patching Options

**Option 1: Disable Sentry**
- Replace DSN with invalid string
- Errors won't be reported

**Option 2: Redirect to Own Sentry**
- Replace `sentry.hytale.com` with own Sentry host
- Requires same-length domain or binary patching

**Option 3: Leave As-Is**
- Errors still report to Hypixel
- May expose F2P server information

### 6.4 Sentry Environment Variables

Found configuration references:
- `SENTRY_DSN` - DSN override
- `SENTRY_ENVIRONMENT` - Environment name
- Docs: `https://docs.sentry.io/platforms/dotnet/configuration/environments`

---

## 7. Internal Class References

### 7.1 Package Structure

```
com.hypixel.hytale/
├── builtin/
│   ├── buildertools/
│   │   ├── imageimport/
│   │   │   └── ImageImportPage
│   │   ├── objimport/
│   │   │   └── ObjImportPage
│   │   ├── prefabeditor/
│   │   │   └── ui/PrefabEditorLoadSettings
│   │   └── prefablist/
│   │       └── PrefabPage
│   ├── instances/
│   │   └── page/InstanceListPage
│   └── model/
│       └── pages/ChangeModelPage
├── server/
│   └── core/
│       └── asset/
│           └── type/
│               └── particle/
│                   └── pages/ParticleSpawn*
└── Creation/
    └── navigation/
        ├── buildertools/
        └── worldtools/
            ├── changeModel
            ├── importImage
            ├── importObj
            ├── instance
            ├── playSound
            ├── prefabEditor
            ├── prefabList
            ├── spawnEntity
            ├── spawnParticle
            └── tintChunk
```

### 7.2 UI Components

| Component | Path | Purpose |
|-----------|------|---------|
| GameLoading | `/GameLoading.u` | Loading screen |
| GamePageNavigation | `/GamePageNavigation.u` | Main navigation |
| ServerButton | `/ServerButton.u` | Server list button |
| ServerModal | `/ServerModal.u` | Server details modal |
| ServersPage | `/Servers/ServersPage.u` | Server browser |
| DirectConnectPopup | `/Servers/DirectConnectPopup.u` | Direct connect dialog |
| EditServerPopup | `/Servers/EditServerPopup.u` | Edit server dialog |
| JoinViaCodePopup | `/Servers/JoinViaCodePopup.u` | Join via code dialog |
| MinigamesPage | `/Minigames/MinigamesPage.u` | Minigames browser |

### 7.3 Configuration Files

| File | Purpose |
|------|---------|
| `/GameplayConfigs/Default.json` | Default gameplay settings |
| `hytale_plugin.js` | Blockbench plugin script |
| `hytale_assets` | Asset reference |

---

## 8. Binary Offsets Reference

### 8.1 URL String Offsets (macOS binary)

| Offset | Content | Length |
|--------|---------|--------|
| `0x1bf0098` | `https://account-data` | ~21 chars |
| `0x1bf00c9` | `https://aka.ms/dotnet-warnings/{0}` | ~35 chars |
| `0x1bf0114` | `https://blockbench.net/downloads` | ~33 chars |
| `0x1bf015d` | `https://blockbench.net/plugins/hytale_plugin` | ~45 chars |
| `0x1bf01bc` | `https://...@sentry.hytale.com/` | ~60 chars |
| `0x1bf023b` | `https://discord.gg/hytale` | ~26 chars |
| `0x1bf0274` | `https://hytale.com/help/joining-friends` | ~40 chars |
| `0x1bf02c9` | `https://sessions` | ~17 chars |
| `0x1bf02f2` | `https://store.hytale.com/?upgrade=` | ~35 chars |
| `0x1bf033d` | `https://telemetry` | ~18 chars |
| `0x1bf0368` | `https://tools` | ~14 chars |

### 8.2 API Endpoint Offsets

| Offset | Endpoint |
|--------|----------|
| `0x1b115d2` | `/game-session/child` |
| `0x1b115ff` | `/game-session/refresh` |
| `0x1b117c2` | `/server-join/auth-grant` |
| `0x1b117f7` | `/server-join/auth-token` |
| `0x1b11689` | `/my-account/cosmetics` |
| `0x1b116ba` | `/my-account/game-profile` |
| `0x1b116f1` | `/my-account/skin` |
| `0x1b10d8c` | `/.well-known/jwks.json` |

### 8.3 Notes on Offsets

- Offsets are for the macOS binary
- Windows/Linux binaries will have different offsets
- Offsets may change between game versions
- Always verify offsets before patching

---

## 9. Implementation Notes

### 9.1 Current Auth Server Implementation

The auth server (`hytale-auth-server`) currently implements:

**Fully Implemented:**
- [x] `/game-session/new` - Session creation
- [x] `/game-session/refresh` - Token refresh
- [x] `/server-join/auth-grant` - Auth grants
- [x] `/server-join/auth-token` - Token exchange with cert binding
- [x] `/my-account/cosmetics` - Cosmetic list
- [x] `/my-account/game-profile` - Profile get/update
- [x] `/my-account/skin` - Skin save
- [x] `/.well-known/jwks.json` - JWKS endpoint
- [x] `/profile/uuid/{uuid}` - UUID lookup
- [x] `/profile/username/{username}` - Username lookup
- [x] Telemetry endpoints (accept and discard)

**Not Implemented:**
- [ ] `tools.hytale.com` API (asset upload/download)
- [ ] Prefab cloud storage
- [ ] Asset sharing between players

### 9.2 Tools Service Implementation (Future)

If implementing tools.hytale.com functionality:

```javascript
// Suggested endpoints for auth-server

// Asset upload
app.post('/tools/assets/upload', async (req, res) => {
  // Handle multipart file upload
  // Store in local filesystem or S3
  // Return asset ID
});

// Asset download
app.get('/tools/assets/:assetId', async (req, res) => {
  // Retrieve asset by ID
  // Stream file to client
});

// Prefab operations
app.post('/tools/prefabs', async (req, res) => {
  // Save prefab JSON
  // Associate with user
});

app.get('/tools/prefabs/:prefabId', async (req, res) => {
  // Get prefab by ID
});

app.get('/tools/prefabs', async (req, res) => {
  // List user's prefabs
});

app.delete('/tools/prefabs/:prefabId', async (req, res) => {
  // Delete prefab
});
```

### 9.3 Patching Recommendations

**Essential (Already Done):**
1. Patch `sessions.hytale.com` → F2P domain
2. Patch `account-data.hytale.com` → F2P domain
3. Patch `telemetry.hytale.com` → F2P domain (or disable)

**Optional Enhancements:**
1. Patch `tools.hytale.com` → F2P domain (if implementing tools API)
2. Patch `sentry.hytale.com` → Own Sentry or disable
3. Patch `discord.gg/hytale` → Community Discord
4. Patch `store.hytale.com` → Custom store (if applicable)

**Not Recommended to Patch:**
- Blockbench URLs (useful for modding)
- Microsoft documentation URLs
- Graphics reference URLs

### 9.4 Security Considerations

1. **Sentry DSN Exposure**
   - Current: Errors report to Hypixel's Sentry
   - Risk: May expose F2P server details
   - Recommendation: Disable or redirect

2. **Telemetry Data**
   - Current: Accepted but discarded
   - Alternative: Log for analytics
   - Risk: Privacy concerns

3. **Asset Upload (if implemented)**
   - Validate file types
   - Limit file sizes
   - Scan for malicious content
   - Rate limit uploads

---

## Appendix A: String Extraction Commands

### Extract UTF-16LE Strings
```bash
python3 << 'EOF'
with open("HytaleClient", "rb") as f:
    data = f.read()

pattern = b'h\x00t\x00t\x00p\x00s\x00:\x00/\x00/\x00'
idx = 0
while True:
    idx = data.find(pattern, idx)
    if idx == -1:
        break
    end = idx
    chars = []
    while end < len(data) - 1:
        char = data[end] | (data[end+1] << 8)
        if 0x20 <= char <= 0x7e:
            chars.append(chr(char))
            end += 2
        else:
            break
    print(f"{hex(idx)}: {''.join(chars)}")
    idx += 2
EOF
```

### Search for Specific Pattern
```bash
xxd HytaleClient | grep "h.y.t.a.l.e"
```

### Extract Context Around Offset
```bash
dd if=HytaleClient bs=1 skip=$((0x1bf0000)) count=2048 | xxd
```

---

## Appendix B: Version History

| Date | Changes |
|------|---------|
| 2026-01-27 | Initial analysis of macOS client binary |

---

## Appendix C: Related Documentation

- `CLAUDE.md` - Project overview and architecture
- `DUAL_AUTH_FLOW.md` - Dual authentication flow diagrams
- `STEAMDECK_CRASH_INVESTIGATION.md` - libzstd crash fix
- `PLAYER_PASSWORD_FEATURE.md` - Planned password authentication
- `backend/utils/clientPatcher.js` - Client patcher implementation