**Signal** - мобильное приложение, разработанное Signal Messenger LLC. The app provides instant messaging and calls secured with the Signal Protocol, an extremely secure encryption protocol which supports forward secrecy[^1] and post-compromise security.[^2]
3. Enter a username. Your username will always be paired with a unique set of digits to keep your username unique and prevent people from guessing it, for example if you enter "John" your username might end up being `@john.35`. By default, only 2 digits are paired with your username when you create it, but you can add more digits until you reach the username length limit (32 characters).
4. Go back to the main app settings page and select **Privacy**.
5. Select **Phone Number**
6. Change the **Who Can See My Number** setting to: **Nobody**
You can optionally change the **Who Can Find Me By Number** setting to **Nobody** as well, if you want to prevent people who already have your phone number from discovering your Signal account/username.
Contact lists on Signal are encrypted using your Signal PIN and the server does not have access to them. Личные профили также шифруются и предоставляются только тем контактам, с которыми вы переписываетесь. Signal supports [private groups](https://signal.org/blog/signal-private-group-system), where the server has no record of your group memberships, group titles, group avatars, or group attributes. Signal has minimal metadata when [Sealed Sender](https://signal.org/blog/sealed-sender) is enabled. Адрес отправителя шифруется вместе с текстом сообщения, серверу виден только адрес получателя. Функция запечатанного отправителя включена только для людей из вашего списка контактов, но может быть включена для всех получателей с повышенным риском получения спама.
Протокол прошел независимый [аудит](https://eprint.iacr.org/2016/1013.pdf) в 2016 году. The specification for the Signal protocol can be found in their [documentation](https://signal.org/docs).
[Настройка и усиление безопасности Signal :material-arrow-right-drop-circle:](https://blog.privacyguides.org/2022/07/07/signal-configuration-and-hardening)
If you use Android and your threat model requires protecting against [:material-target-account: Targeted Attacks](basics/common-threats.md#attacks-against-specific-individuals ""){.pg-red} you may consider using this alternative app, which features a number of security and usability improvements, to access the Signal network.
**Molly** is an alternative Signal client for Android which allows you to encrypt the local database with a passphrase at rest, to have unused RAM data securely shredded, to route your connection via Tor, and [more](https://blog.privacyguides.org/2022/07/07/signal-configuration-and-hardening#privacy-and-security-features). It also has usability improvements including scheduled backups, automatic locking, [UnifiedPush](https://unifiedpush.org) support, and the ability to use your Android phone as a linked device instead of the primary device for a Signal account.
Molly is updated every two weeks to include the latest features and bug fixes from Signal. The exception is security issues, which are patched as soon as possible. That said, you should be aware that there might be a slight delay compared to upstream, which may affect actions such as [migrating from Signal to Molly](https://github.com/mollyim/mollyim-android/wiki/Migrating-From-Signal#migrating-from-signal).
Note that you are trusting multiple parties by using Molly, as you now need to trust the Signal team *and* the Molly team to deliver safe and timely updates.
There is a version of Molly called **Molly-FOSS** which removes proprietary code like the Google services used by both Signal and Molly, at the expense of some features like battery-saving push notifications via Google Play Services. You can regain push notifications without Google Play Services in either version of Molly with [UnifiedPush](https://unifiedpush.org), but it requires running a separate program called [Mollysocket](https://github.com/mollyim/mollysocket) on another device to function. Mollysocket can either be self-hosted on a separate computer or server (VPS), or alternatively a public Mollysocket instance can be used ([step-by-step tutorial, in German](https://kuketz-blog.de/messenger-wechsel-von-signal-zu-molly-unifiedpush-mollysocket-ntfy)).
Molly and Molly-FOSS support [reproducible builds](https://github.com/mollyim/mollyim-android/tree/main/reproducible-builds), meaning it's possible to confirm that the compiled APKs match the source code.
**SimpleX Chat** is an instant messenger that doesn't depend on any unique identifiers such as phone numbers or usernames. Its decentralized network makes SimpleX Chat an effective tool against [:material-close-outline: Censorship](basics/common-threats.md#avoiding-censorship){ .pg-blue-gray }.
SimpleX provides direct messaging, group chats, and E2EE calls secured with the [SimpleX Messaging Protocol](https://github.com/simplex-chat/simplexmq/blob/stable/protocol/simplex-messaging.md), which uses double ratchet encryption with quantum resistance. Additionally, SimpleX Chat provides metadata protection by using unidirectional ["simplex queues"](https://github.com/simplex-chat/simplexmq/blob/stable/protocol/simplex-messaging.md#simplex-queue) to deliver messages.
To participate in conversations on SimpleX Chat, you must scan a QR code or click an invite link. This allows you to verify a contact out-of-band, which protects against man-in-the-middle attacks by network providers. Your data can be exported and imported onto another device, as there are no central servers where this is backed up.
You can find a full list of the privacy and security [features](https://github.com/simplex-chat/simplex-chat#privacy-and-security-technical-details-and-limitations) implemented in SimpleX Chat on the app's repository.
SimpleX Chat was independently audited in [July 2024](https://simplex.chat/blog/20241014-simplex-network-v6-1-security-review-better-calls-user-experience.html#simplex-cryptographic-design-review-by-trail-of-bits) and in [October 2022](https://simplex.chat/blog/20221108-simplex-chat-v4.2-security-audit-new-website).
**Briar** is an encrypted instant messenger that [connects](https://briarproject.org/how-it-works) to other clients using the Tor Network, making it an effective tool at circumventing [:material-close-outline: Censorship](basics/common-threats.md#avoiding-censorship){ .pg-blue-gray }. Briar также может передавать сообщения через Wi-Fi или Bluetooth, если получатель находится в непосредственной близости. Режим локальной сети Briar может быть полезен, когда Вы не имеете доступа к Интернету.
To add a contact on Briar, you must both add each other first. You can either exchange `briar://` links or scan a contact’s QR code if they are nearby.
The client software was independently [audited](https://briarproject.org/news/2017-beta-released-security-audit), and the anonymous routing protocol uses the Tor network which has also been audited.
Briar supports forward secrecy[^1] by using the Bramble [Handshake](https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BHP.md) and [Transport](https://code.briarproject.org/briar/briar-spec/blob/master/protocols/BTP.md) protocol.
These messengers do not have forward secrecy[^1], and while they fulfill certain needs that our previous recommendations may not, we do not recommend them for long-term or sensitive communications. Любая компрометация ключа среди получателей сообщений повлияет на конфиденциальность **всех** прошлых сообщений.
**Element** is the flagship client for the [Matrix](https://matrix.org/docs/chat_basics/matrix-for-im) protocol, an [open standard](https://spec.matrix.org/latest) for secure decentralized real-time communication.
With the integration of [Element Call](https://element.io/blog/we-have-lift-off-element-x-call-and-server-suite-are-ready) into Element's web app, desktop apps, and its [rewritten mobile apps](https://element.io/blog/element-x-experience-the-future-of-element), group VoIP and video calls are E2EE by default.
The Matrix protocol itself [theoretically supports forward secrecy](https://gitlab.matrix.org/matrix-org/olm/blob/master/docs/megolm.md#partial-forward-secrecy)[^1], however this is [not currently supported in Element](https://github.com/vector-im/element-web/issues/7101) due to it breaking some aspects of the user experience such as key backups and shared message history.
The protocol was independently [audited](https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-encryption-security-assessment-released-and-implemented-cross-platform-on-riot-at-last) in 2016. The specification for the Matrix protocol can be found in their [documentation](https://spec.matrix.org/latest). The [Olm cryptographic ratchet](https://matrix.org/docs/matrix-concepts/end-to-end-encryption) used by Matrix is an implementation of Signal’s [Double Ratchet algorithm](https://signal.org/docs/specifications/doubleratchet).
**Session** - это децентрализованный мессенджер, ориентированный на приватные, безопасные и анонимные коммуникации. Session предлагает поддержку обычных чатов, групповых чатов и голосовых вызовов.
Session uses the decentralized [Oxen Service Node Network](https://oxen.io) to store and route messages. Каждое зашифрованное сообщение проходит через три узла в сети Oxen Service Node Network, что делает практически невозможным для узлов собрать значимую информацию о тех, кто пользуется сетью.
Session allows for E2EE in one-on-one chats or closed groups which allow for up to 100 members. It is also possible to [set up](https://docs.oxen.io/oxen-docs/products-built-on-oxen/session/guides/open-group-setup) or join open groups which can host thousands of members, but messages in these open groups are **not** end-to-end encrypted between participants.
Session was previously based on Signal Protocol before replacing it with their own in December 2020. Session Protocol does [not](https://getsession.org/blog/session-protocol-technical-information) support forward secrecy.[^1]
**Обрати внимание, что у нас нет связей ни с одним проектом, который мы рекомендуем.** В дополнение к [нашим стандартным критериям](about/criteria.md) мы разработали четкий набор требований, позволяющий давать объективные рекомендации. Перед тем, как вы решите выбрать какой-либо проект, мы рекомендуем вам ознакомиться со списком критериев и провести собственное исследование, чтобы убедиться в правильности своего выбора.
Эти критерии представляют собой то, что мы хотели бы видеть от идеального проекта в этой категории. Наши рекомендации могут не соответствовать всем или нескольким из этих критериев, но проекты, которые им соответствуют, расположены выше остальных.
[^1]: [Forward secrecy](https://en.wikipedia.org/wiki/Forward_secrecy) is where keys are rotated very frequently, so that if the current encryption key is compromised, it does not expose **past** messages as well.
[^2]: Future Secrecy (or Post-Compromise Security) is a feature where an attacker is prevented from decrypting **future** messages after compromising a private key, unless they compromise more session keys in the future as well. This effectively forces the attacker to intercept all communication between parties, since they lose access as soon as a key exchange occurs that is not intercepted.
