离线加密局域网通讯工具 / Offline Encrypted LAN Chat
OfflineChat 是一款无需互联网连接的局域网加密通讯应用。在同一局域网（WiFi、热点、有线网络）内，设备之间可以直接进行加密聊天，无需任何中心化服务器。
任何一台设备都可以成为"房主"，启动聊天室服务；其他设备通过 UDP 广播自动发现房间，或手动输入 IP 地址加入。
- 完全离线 — 无需互联网，局域网内即可通讯
- 端到端加密 — AES-256-CBC + PBKDF2 密钥派生，消息内容全程加密
- 私聊加密 — 基于 ECDH 密钥交换，每对用户拥有独立密钥
- 群组加密 — 小群组消息使用群组共享密钥
- 消息伪装 — 将加密消息伪装成天气预报、代码日志、购物清单等无害内容
- UDP 广播发现 — 自动发现同一网络内的聊天室
- 房间管理 — 支持密码保护、审批加入机制
- 多语言 — 支持 10 种语言，包括 RTL 布局（阿拉伯语、波斯语）
- 举报系统 — 支持举报不当消息
- 跨平台 — 基于 Expo/React Native，支持 Android、iOS、Web
| 语言 | 代码 | RTL |
|---|---|---|
| 简体中文 | zh-CN | |
| 繁体中文 | zh-TW | |
| English | en | |
| Français | fr | |
| Русский | ru | |
| Español | es | |
| العربية | ar | ✓ |
| فارسی | fa | ✓ |
| 日本語 | ja | |
| 한국어 | ko |
| 层级 | 技术 |
|---|---|
| 前端 | Expo 54 + React Native + TypeScript |
| 后端 | Express.js + WebSocket |
| 加密 | CryptoJS (AES-256-CBC, PBKDF2, ECDH) |
| 网络 | TCP/UDP (react-native-tcp-socket) |
| 样式 | Tailwind CSS (Uniwind) |
| 路由 | Expo Router |
├── client/ # React Native 前端
│ ├── app/ # Expo Router 路由目录
│ ├── screens/ # 页面实现
│ │ ├── home/ # 首页（昵称设置 + 服务器发现）
│ │ ├── chatRoom/ # 聊天室
│ │ ├── createRoom/ # 创建房间
│ │ ├── nickname/ # 昵称设置
│ │ └── language/ # 语言切换
│ ├── i18n/ # 国际化模块
│ │ └── translations/ # 10 种语言翻译文件
│ ├── utils/ # 工具函数
│ │ ├── crypto.ts # 加密模块
│ │ ├── disguise.ts # 消息伪装
│ │ ├── mobileServer.ts # 移动端 TCP 服务
│ │ ├── deviceIdentity.ts # 设备身份
│ │ └── storage.ts # 本地存储
│ └── hooks/ # 自定义 Hooks
├── server/ # Express.js 后端
│ └── src/
│ ├── index.ts # 服务入口
│ ├── chatManager.ts # 聊天管理
│ └── broadcast.ts # UDP 广播
└── package.json
# 安装依赖
pnpm install
# 启动开发环境
coze dev
# 静态检查
pnpm -w lint:all- 所有消息在发送前使用 AES-256-CBC 加密，密钥通过 PBKDF2 从共享密钥派生
- 私聊消息使用 ECDH 密钥交换，确保只有对话双方可以解密
- 消息伪装功能可将加密内容伪装成无害文本，防止被识别为加密通讯
- 本工具仅用于合法的局域网通讯场景，请遵守当地法律法规
Hippocratic License 3.0 — 基于 MIT，附加人权条款。 引用《世界人权宣言》，禁止将本软件用于侵犯人权的活动。
OfflineChat is an encrypted LAN communication app that works without internet access. Devices on the same local network (WiFi, hotspot, wired network) can chat securely with each other — no centralized server required.
Any device can become a "room owner" and start a chat room service. Other devices automatically discover rooms via UDP broadcast, or join manually by entering an IP address.
- Fully Offline — No internet needed, works on any local network
- End-to-End Encryption — AES-256-CBC + PBKDF2 key derivation, all messages encrypted in transit
- Private Chat Encryption — ECDH key exchange, each pair of users has a unique shared secret
- Group Encryption — Small group messages use a shared group key
- Message Disguise — Disguise encrypted messages as weather reports, code logs, shopping lists, or system logs
- UDP Broadcast Discovery — Automatically discover chat rooms on the same network
- Room Management — Password protection and approval-based joining
- Multi-Language — 10 languages supported, including RTL layouts (Arabic, Persian)
- Report System — Report inappropriate messages
- Cross-Platform — Built with Expo/React Native for Android, iOS, and Web
| Language | Code | RTL |
|---|---|---|
| Simplified Chinese | zh-CN | |
| Traditional Chinese | zh-TW | |
| English | en | |
| Français | fr | |
| Русский | ru | |
| Español | es | |
| العربية | ar | ✓ |
| فارسی | fa | ✓ |
| 日本語 | ja | |
| 한국어 | ko |
| Layer | Technology |
|---|---|
| Frontend | Expo 54 + React Native + TypeScript |
| Backend | Express.js + WebSocket |
| Encryption | CryptoJS (AES-256-CBC, PBKDF2, ECDH) |
| Network | TCP/UDP (react-native-tcp-socket) |
| Styling | Tailwind CSS (Uniwind) |
| Routing | Expo Router |
├── client/ # React Native Frontend
│ ├── app/ # Expo Router routes
│ ├── screens/ # Screen implementations
│ │ ├── home/ # Home (nickname + server discovery)
│ │ ├── chatRoom/ # Chat room
│ │ ├── createRoom/ # Create room
│ │ ├── nickname/ # Nickname setup
│ │ └── language/ # Language switch
│ ├── i18n/ # Internationalization
│ │ └── translations/ # 10 language files
│ ├── utils/ # Utilities
│ │ ├── crypto.ts # Encryption module
│ │ ├── disguise.ts # Message disguise
│ │ ├── mobileServer.ts # Mobile TCP server
│ │ ├── deviceIdentity.ts # Device identity
│ │ └── storage.ts # Local storage
│ └── hooks/ # Custom Hooks
├── server/ # Express.js Backend
│ └── src/
│ ├── index.ts # Server entry
│ ├── chatManager.ts # Chat management
│ └── broadcast.ts # UDP broadcast
└── package.json
# Install dependencies
pnpm install
# Start development environment
coze dev
# Run static checks
pnpm -w lint:all- All messages are encrypted with AES-256-CBC before sending, keys derived via PBKDF2 from a shared secret
- Private chat messages use ECDH key exchange, ensuring only the two participants can decrypt
- Message disguise feature can camouflage encrypted content as innocuous text to avoid detection as encrypted communication
- This tool is intended for legitimate LAN communication scenarios only. Please comply with local laws and regulations
Hippocratic License 3.0 — Based on MIT with a human rights clause. References the Universal Declaration of Human Rights. Prohibits use of the software for activities that violate human rights.