免费模式如何支撑其安全实现？

How does the free model support its security implementation?

开源代码使加密与密钥处理可被独立审计，无广告、无订阅、无数据采集则消除了将数据变现的激励，免费与安全可长期并存。

Open source lets the encryption and key handling be independently audited, while no ads, subscriptions, or data collection removes any incentive to monetize data — free and secure coexist long term.

安装包的供应链风险如何规避？

How is supply-chain risk for installers avoided?

安装包应仅来自官方入口，并对分发过程保持溯源；第三方下载站的安装包可能在编译后被打包篡改，须避免经该渠道获取。

Installers should come only from official entries with traceable distribution; third-party download sites may repackage binaries after compilation and must be avoided.

桌面扫码登录的校验逻辑是什么？

How does desktop QR login verification work?

扫码校验将桌面设备与已登录账号绑定，替代在桌面端直接输入账号凭据的方式，减少凭据在本机的暴露范围，降低冒用风险。

The scan binds the desktop device to an already-authenticated account, replacing credential entry on the desktop and shrinking the local credential exposure surface.

密文流转如何界定服务端可见性？

How does ciphertext flow bound server visibility?

消息在发送端加密、接收端解密，服务端仅处理密文的存储与路由，不持有解密所需密钥，因而无法获知明文内容。

Messages encrypt at the sender and decrypt at the receiver; the server only stores and routes ciphertext without holding decryption keys, so plaintext never appears there.

客户端侧还有哪些可配置的防护面？

What configurable protections exist on the client?

应用锁、防截屏与阅后即焚分别约束本机访问、屏幕输出与消息留存，叠加强密码与双重验证，可覆盖多类越权读取路径。

App lock, screenshot protection, and self-destruct respectively constrain local access, screen output, and message retention; strong passwords plus two-factor verification cover further unauthorized-read paths.