Signal-Android

A private messenger for Android.

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deltachat-android

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A Matrix collaboration client for Android.

berty

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Berty is a secure peer-to-peer messaging app that works with or without internet access, cellular data or trust in the network

Quick Overview

Signal-Android is the official Android client for the Signal private messaging system. It provides end-to-end encrypted communication for text messages, voice calls, and video calls, emphasizing user privacy and security. The app is open-source, allowing for community review and contributions.

Pros

Strong focus on privacy and security with end-to-end encryption
Open-source, allowing for transparency and community contributions
Regular updates and active development
Cross-platform support (Android, iOS, and Desktop)

Cons

Requires phone number for registration, which may compromise anonymity
Limited features compared to some other messaging apps
Smaller user base compared to mainstream messaging apps
Occasional syncing issues between devices

Code Examples

As Signal-Android is a full application rather than a code library, specific code examples are not applicable. However, developers interested in contributing or learning from the project can explore the source code on GitHub.

Getting Started

Since Signal-Android is an end-user application, there's no code-based getting started process. Users can download the app from the Google Play Store or F-Droid. Developers interested in contributing to the project can follow these steps:

Fork the repository on GitHub
Clone your fork: git clone https://github.com/your-username/Signal-Android.git
Set up the development environment as per the instructions in the repository's README
Make changes and submit pull requests for review

For more detailed information, refer to the project's CONTRIBUTING.md file.

Competitor Comparisons

Signal-iOS

10,798

A private messenger for iOS.

Pros of Signal-iOS

Written in Swift, a modern and safer language compared to Java
Generally smoother UI performance due to native iOS development
Tighter integration with iOS-specific features and APIs

Cons of Signal-iOS

Smaller contributor base, potentially slower development
Less flexibility in terms of device compatibility (iOS only)
More restrictive App Store policies for updates and features

Code Comparison

Signal-iOS (Swift):

func setupNavigationBar() {
    title = NSLocalizedString("SETTINGS_NAV_BAR_TITLE", comment: "")
    navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(donePressed))
}

Signal-Android (Java):

private void setupToolbar() {
    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setTitle(R.string.settings_activity__title);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}

Both repositories implement similar functionality for setting up navigation bars, but Signal-iOS uses Swift's more concise syntax and iOS-specific UIKit framework, while Signal-Android uses Java and Android's native Toolbar class.

deltachat-android

1,113

Email-based instant messaging for Android.

Pros of Delta Chat

Uses existing email infrastructure, allowing for decentralized communication
No need for phone numbers, enhancing privacy and accessibility
Open federation, enabling communication with non-Delta Chat users

Cons of Delta Chat

Less secure than Signal's end-to-end encryption by default
Potentially slower message delivery due to reliance on email servers
Smaller user base and community compared to Signal

Code Comparison

Delta Chat (Kotlin):

override fun createForwardMessage(msg: DcMsg): DcMsg {
    val forwarded = msg.copyAndForward()
    forwarded.viewType = MessageListAdapter.MsgViewType.OUTGOING
    return forwarded
}

Signal (Java):

public static MessageRecord copyMessage(MessageRecord messageRecord) {
    return new MessageRecord.Builder(messageRecord)
            .withId(SecureRandom.getInstance("SHA1PRNG").nextLong())
            .withDateSent(System.currentTimeMillis())
            .withDateReceived(System.currentTimeMillis())
            .withType(MessageTypes.BASE_OUTBOX_TYPE)
            .build();
}

Both projects implement message forwarding functionality, but Delta Chat uses Kotlin while Signal uses Java. Delta Chat's implementation is more concise, leveraging Kotlin's features, while Signal's approach provides more explicit control over the copied message attributes.

element-android

3,355

A Matrix collaboration client for Android.

Pros of Element

Decentralized architecture: Element uses the Matrix protocol, allowing for federated servers and greater user control
More customizable: Offers extensive theming options and server choices
Open ecosystem: Supports third-party integrations and bridges to other platforms

Cons of Element

Steeper learning curve: More complex setup and configuration options
Less widespread adoption: Smaller user base compared to Signal
Performance: Can be slower and more resource-intensive due to its decentralized nature

Code Comparison

Element (Kotlin):

class RoomListViewModel @Inject constructor(
    private val session: Session,
    private val roomListViewModelFactory: RoomListViewModelFactory
) : ViewModel() {
    // Room list management logic
}

Signal (Java):

public class ConversationListViewModel extends ViewModel {
    private final Application application;
    private final ConversationRepository repository;

    public ConversationListViewModel(Application application, ConversationRepository repository) {
        this.application = application;
        this.repository = repository;
    }
    // Conversation list management logic
}

Both projects use MVVM architecture, but Element uses Kotlin while Signal uses Java. Element's codebase tends to be more modern and concise due to Kotlin's features, while Signal's Java code is more verbose but potentially more familiar to some developers.

berty

7,583

Berty is a secure peer-to-peer messaging app that works with or without internet access, cellular data or trust in the network

Pros of Berty

Fully decentralized, peer-to-peer architecture
Supports offline messaging without relying on servers
Open-source protocol that can be implemented by other apps

Cons of Berty

Smaller user base and community compared to Signal
Less mature and potentially less stable than Signal
Fewer features and integrations available

Code Comparison

Signal-Android (Java):

public class SignalServiceMessageSender {
    public void sendMessage(SignalServiceDataMessage message) {
        // Send encrypted message using Signal protocol
    }
}

Berty (Go):

func (s *service) SendMessage(ctx context.Context, req *messengertypes.SendMessage_Request) (*messengertypes.SendMessage_Reply, error) {
    // Send message using Berty protocol
}

Both projects use different programming languages and architectures. Signal-Android is built in Java and relies on centralized servers, while Berty is written in Go and uses a decentralized, peer-to-peer approach. The code snippets show basic message sending functions, highlighting the different implementation styles and protocols used by each project.

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README

Signal Android

Signal is a simple, powerful, and secure messenger.

Signal uses your phone's data connection (WiFi/3G/4G/5G) to communicate securely. Millions of people use Signal every day for free and instantaneous communication anywhere in the world. Send and receive high-fidelity messages, participate in HD voice/video calls, and explore a growing set of new features that help you stay connected. Signalâs advanced privacy-preserving technology is always enabled, so you can focus on sharing the moments that matter with the people who matter to you.

Currently available on the Play Store and signal.org.

Contributing Bug reports

We use GitHub for bug tracking. Please search the existing issues for your bug and create a new one if the issue is not yet tracked!

https://github.com/signalapp/Signal-Android/issues

Joining the Beta

Want to live life on the bleeding edge and help out with testing?

You can subscribe to Signal Android Beta releases here: https://play.google.com/apps/testing/org.thoughtcrime.securesms

If you're interested in a life of peace and tranquility, stick with the standard releases.

Contributing Code

If you're new to the Signal codebase, we recommend going through our issues and picking out a simple bug to fix (check the "easy" label in our issues) in order to get yourself familiar. Also please have a look at the CONTRIBUTING.md, that might answer some of your questions.

For larger changes and feature ideas, we ask that you propose it on the unofficial Community Forum for a high-level discussion with the wider community before implementation.

Contributing Ideas

Have something you want to say about Signal projects or want to be part of the conversation? Get involved in the community forum.

Help

Support

For troubleshooting and questions, please visit our support center!

https://support.signal.org/

Documentation

Looking for documentation? Check out the wiki!

https://github.com/signalapp/Signal-Android/wiki

Legal things

Cryptography Notice

This distribution includes cryptographic software. The country in which you currently reside may have restrictions on the import, possession, use, and/or re-export to another country, of encryption software. BEFORE using any encryption software, please check your country's laws, regulations and policies concerning the import, possession, or use, and re-export of encryption software, to see if this is permitted. See http://www.wassenaar.org/ for more information.

The U.S. Government Department of Commerce, Bureau of Industry and Security (BIS), has classified this software as Export Commodity Control Number (ECCN) 5D002.C.1, which includes information security software using or performing cryptographic functions with asymmetric algorithms. The form and manner of this distribution makes it eligible for export under the License Exception ENC Technology Software Unrestricted (TSU) exception (see the BIS Export Administration Regulations, Section 740.13) for both object code and source code.

License

Licensed under the GNU AGPLv3: https://www.gnu.org/licenses/agpl-3.0.html

Google Play and the Google Play logo are trademarks of Google LLC.

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