Preguntes freqüents

Amb pressa? Pots llegir aquesta ajuda amb tranquil·litat en qualsevol moment dins de l’app, fins i tot sense connexió a Internet.

Què és Delta Chat?

Delta Chat és una aplicació de missatgeria instantània fiable, descentralitzada i segura, disponible per a plataformes mòbils i d’escriptori.

Com puc trobar a les persones amb qui xatejar?

En primer lloc, tingues en compte que Delta Chat és missatgeria privada. No hi ha descobriment públic: tu decideixes sobre els teus contactes.

Ara espera que la connexió s’estableixi.

Si un dels dos no està connectat o la connexió és dolenta, la possibilitat de xatejar es posposa fins que es restableixi la connectivitat.

Enhorabona! A partir d’ara, amb aquest contacte utilitzareu automàticament el xifrat d’extrem a extrem. Si us afegiu mútuament a grups, s’establirà el xifratge punt a punt entre tots els membres.

Perquè un xat és marcat com a “Sol·licitud”?

Al ser missatgeria privada, només les amistats i familia que comparteixis el teu codi QR o l’enllaç d’invitació poden escriure’t.

Les teves amistats poden compartir el teu contacte amb altres amistats, això es mostra com a Sol·licitud

Com puc posar en contacte a dues de les meves amistats?

Adjunta el primer contacte en el xat del segon utilitzant el Paperclip Botó Adjunt → Contacte. També pots afegir un petit missatge introductori.

El segon contacte llavors rebrà una tarjeta i hi podrà premer per iniciar una conversa amb el primer contacte.

Delta Chat permet enviar imatges, vídeos i altres adjunts?

Sí. Es poden enviar imatges, vídeos, fitxers, missatges de veu, etc. utilitzant els botons d’Paperclip Adjunt- o Microphone Missatge de veu.

Per rendiment, les imatges, per defecte, són optimitzades i enviades amb una mida més petita, però pots enviar-les com un fitxer per preservar la original.

Què són els perfils? Com puc canviar entre ells?{#multiple-accounts}

Un perfil és un nom, una imatge i informació adicional per xifrar missatges. Un perfil només existeix en els teu dispositiu(s) i utilitza el servidor per enviar missatges.

Durant la instal·lació de Delta Chat es crea un primer perfil.

Després, pots premer a la teva imatge de perfil, a la part superior esquerra, per Afegir perfils o Canviar de perfil.

Potser vols utilitzar perfils separats per a activitats polítiques, familiars o laborals.

Potser també vols aprendre com utilitzar el mateix perfil en múltiples dispositius.

Qui veu la meva imatge de perfil?

Pots afegir una foto de perfil a la teva configuració. Si escrius als teus contactes o els afegeixes mitjançant un codi QR, la veuran automàticament com la teva foto de perfil.

Per motius de privacitat, ningú no veu la teva foto de perfil fins que no els envies un missatge.

Puc establir una biografia/estat amb Delta Chat? {#signature}

Sí, ho pots fer a Configuració → Perfil → Biografia. Un cop has enviat un missatge a un contacte, aquest el veurà quan consulti les teves dades de contacte.

Què signifiquen Fixar, Silencia i Arxivar?

Use these tools to organize your chats and keep everything in its place:

To use the functions, long tap or right click a chat in the chat list.

Com funcionen els “Missatges Desats”

Saved Messages is a chat that you can use to easily remember and find messages.

Messages stay saved even if they are edited or deleted - may it be by sender, by device cleanup or by disappearing messages of other chats.

Què significa el punt verd?

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”.

What do the ticks shown beside outgoing messages mean?

In groups the second tick means that at least one member has reported back having read the message.

You will only get the second tick if both you and one of the recipients who read the message has Settings → Chats → Read Receipts enabled.

Correct typos and delete messages after sending

While edited messages will have the word “Edited” next to the timestamp, deleted messages will be removed without a marker in the chat. Notifications are not sent and there is no time limit.

Note, that the original message may still be received by chat members who could have already replied, forwarded, saved, screenshotted or otherwise copied the message.

Com funcionen els missatges que desapareixen?

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.

Note that you can rely on disappearing messages only as long as you trust your chat partners; malicious chat partners can take photos, or otherwise save, copy or forward messages before deletion.

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

What happens if I turn on “Delete Messages from Device”?

If you want to save storage on your device, you can choose to delete old messages automatically.

To turn it on, go to Settings → Chats → Delete Message from Device. You can set a timeframe between “after an hour” and “after a year”; this way, all messages will be deleted from your device as soon as they are older than that.

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.

Grups

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.

Creació d’un grup

Afegeix i elimina membres

All group members have the same rights. For this reason, everyone can delete any member or add new ones.

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

M’he esborrat a mi mateix per accident

As you’re no longer a group member, you cannot add yourself again. However, no problem, just ask any other group member in a normal chat to re-add you.

I do not want to receive the messages of a group any longer.

As an alternative, you can also “Mute” a group - doing so means you get all messages and can still write, but are no longer notified of any new messages.

Clonar un grup

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.

How many members can participate in a single group?

There is no strict technical limit, but more than 150 is not recommended.

As groups get larger, they can become socially unstable and may need a hierarchy - where Delta Chat is a private messenger for chatting with equal rights. See Dunbar’s number for more insights.

Apps de xat

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

On puc trobar les apps de xat?

Quin nivell de privacitat tenen les aplicacions de xat?

Com puc crear la meva app de xat?

Lliurament de missatges instantanis i Notificacions Push

What are Push Notifications? How can I get instant message delivery?

Push Notifications are sent by Apple and Google “Push services” to a user’s device so that an inactive Delta Chat app can fetch messages in the background and show notifications on a user’s phone if needed.

Les Notificacions Push funcionen amb tots els servidors de chatmail activats

Are Push Notifications enabled on iOS devices? Is there an alternative?

Yes, Delta Chat automatically uses Push Notifications for chatmail profiles. And no, there is no alternative on Apple’s phones to achieve instant message delivery because Apple devices do not allow Delta Chat to fetch data in the background. Push notifications are automatically activated for iOS users because Delta Chat’s privacy-preserving Push Notification system does not expose data to Apple that it doesn’t already have.

Are Push notifications enabled / needed on Android devices?

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

In the Delta Chat “Notifications” settings for “Instant delivery” you can change the following settings effecting all chat profiles:

Both “Background Connection” options are energy-efficient and safe to try if you experience messages arrive only with long delays.

How private are Delta Chat Push Notifications?

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.

Here is how Delta Chat apps perform Push Notification delivery:

The central Delta Chat notification proxy is small and fully implemented in Rust and forgets about device-tokens as soon as Apple/Google/etc processed them, usually in a matter of milliseconds.

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).

Resulting from this overall privacy design, even the seizure of a chatmail server, or the full seizure of the central Delta Chat notification proxy would not reveal private information that Push services do not already have.

Why does Delta Chat integrate with centralized proprietary Apple/Google push services?

Delta Chat is a free and open source decentralized messenger with free server choice, but we want users to reliably experience “instant delivery” of messages, like they experience from WhatsApp, Signal or Telegram apps, without asking questions up-front that are more suited to expert users or developers.

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 :)

Multi-client

Can I use Delta Chat on multiple devices at the same time?

Sí. You can use the same profile on different devices:

In contrast to many other messengers, after successful transfer, both devices are completely independent. One device is not needed for the other to work.

Resolució de problemes

Transferència Manual

This method is only recommended if “Add Second Device” as described above does not work.

Ja esteu sincronitzats i podeu utilitzar els dos dispositius per enviar i rebre missatges xifrats d’extrem a extrem amb els vostres contactes.

Are there any plans for introducing a Delta Chat Web Client?

Avançat

Funcionalitats experimentals

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.

Què són els relés?

Relays are used to temporarily hold messages in case your device is offline. Relays are cheap and dumb servers, that do not store data as group states, your name or avatar - all that exist only on your device. Relays are operated by different groups and people.

By default, after installation, a relay is automatically set up, so you do not need to care about that. However, if you want to, you can configure relays at At Settings → Advanced → Relays:

For more details and future possibilities of relays, you can follow discussions in the Forum.

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:

Les aplicacions que no són de chatmail, en general, no aconsegueixen oferir xifratge automàtic d’extrem a extrem per correu electrònic als seus usuaris, mentre que les aplicacions i els relés de chatmail apliquen de manera omnipresent el xifrat d’extrem a extrem i els estàndards de seguretat.

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

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 Relay. 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.

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.

Ens interessen, per exemple, estadístiques com ara:

We will not collect any personally identifiable information about you.

I’m interested in the technical details. Can you tell me more?

See Standards used in Delta Chat.

Encriptació i Seguretat

Quins estàndards s’utlitzen per una xifrat d’extrem a extrem?

Delta Chat utilitza un subconjunt segur de l’estandard OpenPGP Oferint xifrat d’extrem a extrem automàtic utilitzant aquests protocols:

Delta Chat does not query, publish or interact with any OpenPGP key servers.

Com puc saber si els missatges són xifrats d’extrem a extrem?

Tots els missatges a Delta Chat són xifrats d’extrem a extrem per defecte. Desde el llançament de la versió 2 de Delta Chat (Juliol 2025) ja no hi haurà més candaus o marques semblants als missatges xifrats d’extrem a extrem.

Encara es pot rebre missatges sense xifrat d’extrem a extrem?

Si utilitzes el relé de chatmail per defecte, no és possible de rebre o enviar missatges sense xifrat d’extrem a extrem.

Si enlloc d’això utilitzes un servidor de correu clàssic, podràs enviar i rebre missatges amb o sense xifrat d’extrem a extrem. Els missatges que no vagin xifrats d’extrem a extrem es marcaran amb la icona de correu-e 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.

Per a una discussió més profunda sobre el “xifratge d’extrem a extrem garantit”, consulteu els protocols Secure-Join i llegiu específicament sobre els “Grups Verificats”, el terme tècnic que designa el que aquí s’anomenen xats amb “marcat de verificació verda” o de “xifratge d’extrem a extrem garantit”.

Els adjunts (imatges, fitxers, audio, etc.) es xifren d’extrem a extrem?

Sí.

Quan parlem d’un “missatge xifrat d’extrem a extrem”, sempre ens referim a un missatge xifrat sencer, incloent-hi tots els fitxers adjunts i les metadades d’aquests, com ara els noms de fitxer.

És OpenPGP segur?

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 is not insecure by itself. Most publicly discussed OpenPGP security problems actually stem from bad usability or bad implementations of tools or apps (or both). It is particularly important to distinguish between OpenPGP, the IETF encryption standard, and GnuPG (GPG), a command line tool implementing OpenPGP. Many public critiques of OpenPGP actually discuss GnuPG which Delta Chat has never used. Delta Chat rather uses the OpenPGP Rust implementation rPGP, available as an independent “pgp” package, and security-audited in 2019 and 2024.

We aim, along with other OpenPGP implementors, to further improve security characteristics by implementing the new IETF OpenPGP Crypto-Refresh which was thankfully adopted in summer 2023.

Heu considerat utilitzar alternatives a l’OpenPGP per al xifratge d’extrem a extrem?

Sí, estem seguint iniciatives com MLS, però adoptar-les significaria trencar la interoperabilitat del xifrat d’extrem a extrem. Per tant, no seria una decisió fàcil de prendre i hi hauria d’haver millores tangibles per a les usuaries.

Delta Chat adopta un enfocament holístic de “seguretat usable” i treballa amb una àmplia gamma de col·lectius activistes, així com amb investigadors de renom com TeamUSEC, per millorar els resultats reals dels usuaris davant de les amenaces de seguretat. El protocol i estàndard de xifrat d’extrem a extrem és només una part dels “resultats per a l’usuari”, vegeu les respostes a les preguntes sobre confiscació del dispositiu i metadades dels missatge.

És Delta Chat vulnerable a EFAIL?

No, Delta Chat never was vulnerable to EFAIL because its OpenPGP implementation rPGP uses Modification Detection Code when encrypting messages and returns an error if the Modification Detection Code is incorrect.

Delta Chat also never was vulnerable to the “Direct Exfiltration” EFAIL attack because it only decrypts multipart/encrypted messages which contain exactly one encrypted and signed part, as defined by the Autocrypt Level 1 specification.

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

Si envieu o rebeu missatges de correu electrònic sense xifratge de punta a punta (fent servir un servidor de correu electrònic clàssic), encara estan protegits de les companyies de telefonia mòbil o per cable, que no poden llegir ni modificar els vostres missatges de correu electrònic. Però tant el vostre proveïdor de correu electrònic com el del destinatari poden llegir, analitzar o modificar els vostres missatges, inclosos els fitxers adjunts.

Delta Chat utilitza per defecte un xifrat TLS estricte, que protegeix les connexions entre el teu dispositiu i el teu proveïdor de correu electrònic. Tota la gestió de TLS de Delta Chat ha estat objecte d’una auditoria de seguretat independent. A més a més, la connexió entre el vostre proveïdor de correu electrònic i el del destinatari també sol xifrar les comunicacions. Si els servidors de correu electrònic implicats admeten MTA-STS, aleshores es xifraran les comunicacions entre els proveïdors de correu electrònic, i en aquest cas les comunicacions de Delta Chat mai no estaran exposades en text pla a Internet, fins i tot si el missatge no estava xifrat d’extrem a extrem.

How does Delta Chat protect metadata in messages?

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.

Per tant, els servidors només poden veure:

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

How to protect metadata and contacts when a device is seized?

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.

Qui veu la meva Adreça IP?

The used relay needs to know your IP Address, as well as sometimes your contact’s devices if you have a call or use apps together.

IP Addresses are needed for connectivity and efficiency. They are neither persisted nor exposed. Note that the IP Address is not like a detailed address you give to a delivery service, but much more coarse, often defining region or country only.

As this is just how the internet and other messengers work by default, we do not offer options here or ask upfront questions.

If you see your IP Address as a security or privacy risk, we recommend to use a VPN, in combination with system lockdown mode. Hunting down options in all apps on your system will leave gaps. For example, tapping a link exposes IP Addresses to unknown parties and is the by far larger risk here.

Delta Chat admet “Remitent Segellat””?

No, encara no.

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.

Does Delta Chat support Perfect Forward Secrecy?

Not yet, but it’s coming with Autocrypt v2.

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.

Autocrypt v2, scheduled for full implementation in 2026, will provide reliable deletion (forward secrecy) through automatic key rotation. This approach is specified in the Autocrypt v2 OpenPGP Certificates draft.

Delta Chat implementa Criptografia Post-Quàntica?

Not yet, but it’s coming with Autocrypt v2.

Autocrypt v2, scheduled for full implementation in 2026, will bring post-quantum resistant encryption to protect against quantum computer attacks. Delta Chat uses the Rust OpenPGP library rPGP which supports the latest IETF Post-Quantum-Cryptography OpenPGP draft. The implementation is specified in the Autocrypt v2 OpenPGP Certificates draft.

Com puc comprobar manualment la informació d’encriptació?

You may check the end-to-end encryption status manually in the “Encryption” dialog (user profile on Android/iOS or right-click a user’s chat-list item on desktop). Delta Chat shows two fingerprints there. If the same fingerprints appear on your own and your contact’s device, the connection is safe.

Can I reuse my existing private key?

No.

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.

Was Delta Chat independently audited for security vulnerabilities?

Yes, multiple times. The Delta Chat project continuously undergoes independent security audits and analysis, from most recent to older:

Miscel·lània

Quins permissos necessita Delta Chat?

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

Consulta la política de privacitat per una visió general detallada.

On poden trobar Delta Chat els meus amics?

Delta Chat is available for all major and some minor platforms:

Com es finança el desenvolupament de Delta Chat?

Delta Chat does not receive any Venture Capital and is not indebted, and under no pressure to produce huge profits, or to sell users and their friends and family to advertisers (or worse). We rather use public funding sources, so far from EU and US origins, to help our efforts in instigating a decentralized and diverse chat messaging eco-system based on Free and Open-Source community developments.

Concretely, Delta Chat developments have so far been funded from these sources, ordered chronologically:

The monetary funding mentioned above is mostly organized by merlinux GmbH in Freiburg (Germany), and is distributed to more than a dozen contributors world-wide.

Please see Delta Chat Contribution channels for both monetary and other contribution possibilities.