常见问题

现在还忙？您可以随时在应用程序中轻松阅读此帮助，即使在离线状态下。

什么是 Delta Chat？

Delta Chat is a reliable, decentralized and secure instant messaging app, available for mobile and desktop platforms.

How can I find people to chat with?

First, note that Delta Chat is a private messenger. There is no public discovery, you decide about your contacts.

Now wait while connection gets established.

Congratulations! You now will automatically use end-to-end encryption with this contact. If you add each other to groups, end-to-end encryption will be established among all members.

Why is a chat marked as “Request”?

As being a private messenger, only friends and family you share your QR code or invite link with can write to you.

Your friends may share your contact with other friends, this appears as a request.

How can I put two of my friends in contact with each other?

Attach the first contact to the chat of the second using Paperclip Attachment Button → Contact. You can also add a little introduction message.

The second contact will receive a card then and can tap it to start chatting with the first contact.

Delta Chat 支持图像、视频和其他附件吗？

什么是账户资料？如何在它们之间切换？

A profile is a name, a picture and some additional information for encrypting messages. A profile lives on your device(s) only and uses the server only to relay messages.

首次安装Delta Chat 时，会创建第一个账户资料文件。

之后，您可以点击左上角的个人资料图像，添加个人账户 或切换账户。

You may want to use separate profiles for political, family or work related activities.

您可能还想了解 如何在多台设备上使用同一账户资料。

谁会看见我的个人资料图片？

Can I set a Bio/Status with Delta Chat?

Yes, you can do so under Settings → Profile → Bio. Once you sent a message to a contact, they will see it when they view your contact details.

固定、静音、归档是什么意思？

使用这些工具来管理您的聊天，让其井然有序：

要归档或固定一个聊天，可以长按（Android）、使用聊天内部的菜单（Android/桌面版）或者左滑（iOS）； 要静音一个聊天，可以使用聊天内部的菜单（Android/桌面版）或者通过聊天概要（iOS）。

“保存的消息”如何工作？

Saved Messages 是专用于存储消息的专属对话窗口，可帮助您便捷存储和快速检索重要信息。

即使消息遭到修改或删除 - 无论是发送者编辑、设备清理操作，还是其他聊天中的临时消息功能所触发 - 这些信息仍将保留在系统中。

绿色圆点代表什么？

You can sometimes see a green dot next to the avatar of a contact. It means they were recently seen by you in the last 10 minutes, e.g. because they messaged you or sent a read receipt.

So this is not a real time online status and others will as well not always see that you are “online”.

显示在发出消息旁边的对勾表示什么？

发送后更正错别字并删除邮件

在聊天场景中，经过编辑的消息会在时间戳旁标注“Edited”提示， 而被删除的信息则会彻底消失且不显示任何痕迹。 相关操作既不会触发系统通知，也没有规定必须在时限内完成修改。

需特别提示：若聊天成员已对消息进行过回复、转发、保存本地、截图留存或其他形式的复制操作， 即使您后续编辑了原始消息，对方设备上仍可能留存原内容。

消息定时销毁是如何工作的？

You can turn on “disappearing messages” in the settings of a chat, at the top right of the chat window, by selecting a time span between 5 minutes and 1 year.

Until the setting is turned off again, each chat member’s Delta Chat app takes care of deleting the messages after the selected time span. The time span begins when the receiver first sees the message in Delta Chat. The messages are deleted both, on the servers, and in the apps itself.

请注意，只有当您信任您的聊天伙伴时，您才可以依赖“消息定时销毁”； 不怀好意的人可能会拍照，或者在删除之前以其他方式保存、复制或转发消息。

Apart from that, if one chat partner uninstalls Delta Chat, the (anyway encrypted) messages may take longer to get deleted from their server.

打开“从设备删除旧消息”后，会发生什么？

How can I delete my chat profile?

If you are using more than one chat profile, you can remove single ones in the top profile switcher menu (on Android and iOS), or in the sidebar with a right click (in the Desktop app). Chat profiles are only removed on the device where deletion was triggered. Chat profiles on other devices will continue to fully function.

If you use a single default chat profile you can simply uninstall the app. This will still automatically trigger deletion of all associated address data on the chatmail server. For more info, please refer to nine.testrun.org address-deletion or the respective page from your chosen 3rd party chatmail server.

Groups

Groups let several people chat together privately with equal rights.

Anyone can change the group name or avatar, add or remove members, set disappearing messages, and delete their own messages from all member’s devices.

Because all members have the same rights, groups work best among trusted friends and family.

创建群组

Add and remove members

QR code and invite link can be used to add several members. However, since groups are meant for trusted people, avoid sharing them publicly.

我不小心删除了我自己。

我不想再收到某个群组中的消息了。

Cloning a group

You can duplicate a group to start a separate discussion or to exclude members without them noticing.

The new group is fully independent from the original, which continues to work as before.

In-chat apps

You can send apps to a chat - games, editors, polls and other tools. This makes Delta Chat a truly extensible messenger.

Where can I get in-chat apps?

How private are in-chat apps?

How can I create my own in-chat apps?

即时消息传递和推送通知

什么是推送通知？如何获得即时消息传递？

推送通知由 Apple 和 Google 的“推送服务”发送到用户的设备，以便非活动状态的 Delta Chat 应用可以在后台获取消息，并在需要时在用户的手机上显示通知。

推送通知适用于以下所有 chatmail 服务器：

iOS 设备上是否启用了推送通知？我还有其他的选择吗？

是的，Delta Chat 会自动使用推送通知来接收 chatmail 个人资料。 而且，Apple 手机上没有其他方式可以实现即时消息传递 因为 Apple 设备不允许 Delta Chat 在后台获取数据。 推送通知会自动为 iOS 用户激活，因为 Delta Chat 的隐私保护推送通知系统 不会向 Apple 泄露其尚未拥有的数据。

Android 设备上是否启用/需要推送通知？

If a “Push Service” is available, Delta Chat enables Push Notifications to achieve instant message delivery for all chatmail users.

在 Delta Chat“通知”的“推送通知”设置中，您可以更改以下影响所有聊天配置文件的设置：

如果消息到达时间延迟较长， 则“后台连接”选项都节能且安全，可以尝试。

Delta Chat 推送通知的隐私性如何？

Delta Chat Push Notification support avoids leakage of private information. It does not leak profile data, IP address or message content (not even encrypted) to any system involved in the delivery of Push Notifications.

以下是 Delta Chat 应用如何执行推送通知传递：

中央 Delta Chat 通知代理体积小，完全用 Rust 实现 ，并在 Apple/Google 等处理设备令牌后立即忘记它们， 通常在几毫秒内。

Note that the device token is encrypted between apps and notification proxy but it is not signed. The notification proxy thus never sees profile data, IP-addresses or any cryptographic identity information associated with a user’s device (token).

由此产生的整体隐私设计，即使查封 Chatmail 服务器， 或完全查封中央 Delta Chat 通知代理 也不会泄露推送服务尚未拥有的私人信息。

为什么 Delta Chat 与集中式专有的 Apple/Google 推送服务集成？

Delta Chat 是一款免费且开源的去中心化即时通讯应用，用户可以自由选择服务器， 但我们希望用户可靠地体验到“即时消息传递”， 就像他们从 Whatsapp、Signal 或 Telegram 应用体验到的那样， 而无需预先提出更适合专家用户或开发人员的问题。

Note that Delta Chat has a small and privacy-preserving Push Notification system that achieves “instant delivery” of messages for all chatmail servers including a potential one you might setup yourself without our permission. Welcome to the power of the interoperable chatmail relay network :)

多客户端

我能同时在多个设备上使用 Delta Chat 吗?

是的，您可以在不同设备上使用相同的配置文件：

与其他许多即时通讯应用不同，在成功传输后， 两台设备完全独立。 一台设备不是另一台设备工作的必要条件。

故障排除

手动传输

仅当上述“添加第二台设备”方法不起作用时，才建议使用此方法。

有推出 Delta Chat Web 客户端的计划吗？

Advanced

Experimental Features

At Settings → Advanced → Experimental Features you can try out features we are working on.

The features may be unstable and may be changed or removed.

You can find more information and give feedback in the Forum.

What is “Send statistics to Delta Chat’s developers”?

We would like to improve Delta Chat with your help, which is why Delta Chat for Android asks whether you want to send anonymous usage statistics.

You can turn it on and off at Settings → Advanced → Send statistics to Delta Chat’s developers.

When you turn it on, weekly statistics will be automatically sent to a bot.

We are interested e.g. in statistics like:

We will not collect any personally identifiable information about you.

Can I use a classic email address with Delta Chat?

Yes, but only if the email address is used exclusively by chatmail clients.

It is not supported to share usage of an email address with non-chatmail apps or web-based mailers, for the following reasons:

How can I configure a chat profile with a classic email address as transport?

First off, please do not use the same classic email address also from non-chatmail classic email apps unless you are prepared to deal with encrypted messages in the inbox, double notifications, accidentally deleted emails or similar annoyances.

You can configure a email address for chatting at New Profile → Use Other Server → Use Classic Mail as Transport. Note that classic email providers will generally not support Push Notifications and have other limitations, see Provider Overview. Chatmail uses the default INBOX for relay; ensure the provider setup does too. A chat profile using a classic email address allows to to send and receive unencrypted messages. These messages, and the chats they appear in, are marked with an email icon email.

I want to manage my own server for Delta Chat. What do you recommend?

Any well behaving email server setup will do fine except if your users’ devices require Google/Apple Push Notifications to work properly.

We generally recommend to set up a chatmail relay. Chatmail is a community-driven project that encompasses both the setup of relays and core Rust developments that power chatmail clients of which Delta Chat is the most well known.

我对技术细节很感兴趣。能告诉我更多吗？

加密和安全

端到端加密使用了哪些标准 ？

Delta Chat 使用 OpenPGP 标准的安全子集 使用以下协议提供自动端到端加密：

Delta Chat 不会查询、发布或与任何 OpenPGP 密钥服务器交互。

How can I know if messages are end-to-end encrypted?

Delta Chat 中的所有消息 默认都采用端到端加密。 自 Delta Chat 版本 2 发布系列（2025 年 7 月）起， 端到端加密消息上不再有锁或类似的标记。

Can I still receive or send messages without end-to-end encryption?

如果您使用默认的 chatmail 中继， 则不可能在没有端到端加密的情况下接收或发送消息。

If you instead use a classic email server, you can send and receive messages with or without end-to-end encryption. Messages lacking end-to-end encryption are marked with an email icon email.

What does the green checkmark in a contact profile mean?

A contact profile might show a green checkmark green checkmark and an “Introduced by” line. Every green-checkmarked contact either did a direct QR-scan with you or was introduced by a another green-checkmarked contact. Introductions happen automatically when adding members to groups. Whoever adds a green-checkmarked contact to a group with only green-checkmarked members becomes an introducer. In a contact profile you can tap on the “Introduced by …” text repeatedly until you get to the one with whom you directly did a QR-scan.

有关“保证的端到端加密”的更深入讨论， 请参阅 安全加入协议， 并专门阅读有关“已验证群组”的内容，这是 此处所谓的“带有绿色复选标记”或“保证的端到端加密”聊天的技术术语。

附件（图片、文件、音频等）是否已端到端加密？

是的。

当我们谈论“端到端加密消息”时， 我们始终指的是整个消息都已加密， 包括所有附件和附件元数据，例如文件名。

OpenPGP 安全吗？

Yes, Delta Chat uses a secure subset of OpenPGP requiring the whole message to be properly encrypted and signed. For example, “Detached signatures” are not treated as secure.

OpenPGP 加密标准本身不存在安全隐患。 目前公众讨论中涉及的 OpenPGP 安全问题， 大多源自相关工具或应用的用户体验缺陷或技术实现漏洞（或二者叠加）。 需特别澄清的是：OpenPGP 作为 IETF 制定的加密标准， 与基于命令行操作的 GnuPG（GPG）工具不可混为一谈。 诸多对 OpenPGP 的质疑实际指向 GnuPG 工具，而 Delta Chat 即时通讯应用从未采用该工具。 Delta Chat 实际使用的是 Rust 语言编写的 OpenPGP 实现库 rPGP， 该库以独立 “pgp” 组件包形式提供， 且已通过 2019 和 2024 年两次安全审计。

我们的目标是与其他 OpenPGP 实现者一起， 通过实施 新的 IETF OpenPGP Crypto-Refresh 来进一步提高安全特性，该标准已于 2023 年夏季获得通过，令人欣慰。

Did you consider using alternatives to OpenPGP for end-to-end-encryption?

Yes, we are following efforts like MLS but adopting them would mean breaking end-to-end encryption interoperability. So it would not be a light decision to take and there must be tangible improvements for users.

Delta Chat 采用整体“可用安全性”方法， 并与广泛的活动家团体以及 TeamUSEC 等知名研究人员合作 ，以改进针对安全威胁的实际用户结果。 用于建立端到端加密的线路协议和标准 只是“用户结果”的一部分， 另请参阅我们对 设备查封 和 消息元数据 问题的回答。

Delta Chat 是否容易受到 EFAIL 攻击？

不，Delta Chat 从未受到任何 EFAIL 攻击 因为所使用的 OpenPGP 实现了 rPGP 在加密消息时“修改检测代码” 并且如果“修改检测代码”不正确则返回 错误。

Delta Chat 也从未容易受到“直接泄露”EFAIL 攻击， 因为它只解密 multipart/encrypted 消息， 这些消息正好包含一个加密和签名的部分， 如 Autocrypt Level 1 规范所定义。

Are messages marked with the mail icon exposed on the Internet?

If you are sending or receiving email messages without end-to-end encryption (using a classic email server), they are still protected from cell or cable companies who can not read or modify your email messages. But both your and your recipient’s email providers may read, analyze or modify your messages, including any attachments.

Delta Chat by default uses strict TLS encryption which secures connections between your device and your email provider. All of Delta Chat’s TLS-handling has been independently security audited. Moreover, the connection between your and the recipient’s email provider will typically be transport-encrypted as well. If the involved email servers support MTA-STS then transport encryption will be enforced between email providers in which case Delta Chat communications will never be exposed in cleartext to the Internet even if the message was not end-to-end encrypted.

Delta Chat 如何保护消息中的元数据？

Unlike most other messengers, Delta Chat apps do not store any metadata about contacts or groups on servers, also not in encrypted form. Instead, all group metadata is end-to-end encrypted and stored on end-user devices, only.

Servers can therefore only see:

By default, the addresses are randomly generated.

All other message, contact and group metadata resides in the end-to-end encrypted part of messages.

当设备被查封时，如何保护元数据和联系人？

Both for protecting against metadata-collecting servers as well as against the threat of device seizure we recommend to use a chatmail relay to create chat profiles using random addresses for transport. Note that Delta Chat apps on all platforms support multiple profiles so you can easily use situation-specific profiles next to your “main” profile with the knowledge that all their data, along with all metadata, will be deleted. Moreover, if a device is seized then chat contacts using short-lived profiles can not be identified easily.

Does Delta Chat support “Sealed Sender”?

No, not yet.

The Signal messenger introduced “Sealed Sender” in 2018 to keep their server infrastructure ignorant of who is sending a message to a set of recipients. It is particularly important because the Signal server knows the mobile number of each account, which is usually associated with a passport identity.

Even if chatmail relays do not ask for any private data (including no phone numbers), it might still be worthwhile to protect relational metadata between addresses. We don’t foresee bigger problems in using random throw-away addresses for sealed sending but an implementation has not been agreed as a priority yet.

Delta Chat 是否支持完美前向保密？

No, not yet.

Delta Chat today doesn’t support Perfect Forward Secrecy (PFS). This means that if your private decryption key is leaked, and someone has collected your prior in-transit messages, they will be able to decrypt and read them using the leaked decryption key. Note that Forward Secrecy only increases security if you delete messages. Otherwise, someone obtaining your decryption keys is typically also able to get all your non-deleted messages and doesn’t even need to decrypt any previously collected messages.

We designed a Forward Secrecy approach that withstood initial examination from some cryptographers and implementation experts but is pending a more formal write up to ascertain it reliably works in federated messaging and with multi-device usage, before it could be implemented in chatmail core, which would make it available in all chatmail clients.

Does Delta Chat support Post-Quantum-Cryptography?

No, not yet.

Delta Chat uses the Rust OpenPGP library rPGP which supports the latest IETF Post-Quantum-Cryptography OpenPGP draft. We aim to add PQC support in chatmail core after the draft is finalized at the IETF in collaboration with other OpenPGP implementers.

How can I manually check encryption information?

你可以在“加密”对话框中手动检查端到端加密状态 （Android/iOS 上的用户配置文件或桌面上的用户聊天列表项上右键单击）。 Delta Chat 在此处显示两个指纹。 如果相同的指纹出现在你自己的设备和你联系人的设备上， 则连接是安全的。

我可以重复使用现有的私钥吗？

不。

Delta Chat generates secure OpenPGP keys according to the Autocrypt specification 1.1. We do not recommend or offer users to perform manual key management. We want to ensure that security audits can focus on a few proven cryptographic algorithms instead of the full breadth of possible algorithms allowed with OpenPGP. If you want to extract your OpenPGP key, there only is an expert method: you need to look it up in the “keypairs” SQLite table of a profile backup tar-file.

Delta Chat 是否已进行独立的安全漏洞审计？

确实如此，且已进行多次。 Delta Chat 长期接受第三方独立机构的安全审计与漏洞分析， 以下按时间倒序列出历年检测记录：

自 2024 年 12 月之后，各应用商店发布的 Delta Chat 版本均已修复上述安全公告提及的问题。 相关更新作为常规版本升级的一部分，现已全面覆盖所有 appstore 平台。

杂项

Delta Chat 需要哪些权限？

Some features require certain permissions, e.g. you need to grant camera permission if you want to scan an invite QR code.

See Privacy Policy for a detailed overview.

我的朋友在哪里可以找到 Delta Chat？

Delta Chat 适用于所有主要平台和一些次要平台：

Delta Chat 的开发是如何被资助的?

Delta Chat 没有接受风险投资，也没有负债累累，更没有承受产生巨额利润或将用户及其朋友和家人卖给广告商（或更糟）的压力。我们宁愿使用目前来自欧盟和美国的公共资金，来帮助我们努力建立一个基于自由开源社区开发的、去中心化的、多样化的聊天消息软件生态系统。

具体而言，Delta Chat 的开发迄今为止已从以下来源获得资金， 按时间顺序排列：

上面提到的钱款资助主要是由在弗赖堡（德国）的 merlinux GmbH 组织的，分发给了来自世界各地的十多位贡献者。

请参阅 Delta Chat 捐款渠道 以了解货币捐款和其他捐款的可能性。