Free and open source encrypted chat for iOS.

ChatSecure v4.0.9 - Sustainable Open Source Starts With You

ChatSecure v4.0.9 - Sustainable Open Source Starts With You

Coffee Beer Gift Heart Emojis

The v4.0.9 release marks the beginning of a fundraising experiment to measure the long term viability of user-driven open source privacy software development. ChatSecure has been around for over five(!) years now, and grown from a small hobby project to a full time mission to prevent the centralization of communication.

This growth wouldn’t have been possible without the generous funding and support of organizations like The Guardian Project, OpenITP, and the Open Technology Fund along the way. The open source privacy software scene would not be nearly as vibrant without grant funding, and many projects you’ve heard of receive large amounts of funding from similar sources.

Unfortunately there are large risks with this funding model:

  • Funders generally do not support ongoing software maintenance. Grants require specific milestones and deliverables.
  • The grant cycle can be very long. It can take over a year and multiple iterations between a concept and secured funding.
  • Even after multiple rounds of negotiation, funders may ultimately decide not to fund your vision.
  • Fundraising is a full time job. For a small team, that means less time can be spent on improving the product.
  • There’s also the elephant in the room. Although “Internet freedom” appropriations may be safe for now, a large chunk of this funding pool could also quickly dry up, leaving many projects scrambling to keep the lights on.

Other funding models don’t work well either for tools in this space. Venture capital is incapable of funding “privacy software” products without eventually introducing something to monetize you by violating your privacy. The upfront cost of paid App Store builds prevents vulnerable users without reliable access to payment services from downloading the app. Services like Patreon may work for some projects, but most rarely receive enough funds to actually pay anyone for development. Offering white labels and consulting services can also work to fund core development, but it doesn’t scale well and can take a considerable amount of time.

❤️ This Is For You

You, the user, are the reason this project exists. We’ve now put the power of direct funding in your hands. There are quite a few of you now, and if a relatively small fraction of you can contribute a few bucks a month, you will prove that open source privacy software development can be sustainable.

You can now show your continued support directly within the app. The current options are ☕️ $2.99/mo, 🍺 $5.99/mo, and 🎁 $19.99/mo. Hopefully these are enough choices for now, and we’re welcome to any feedback or suggestions. If you’re already a supporter, or don’t have the spare cash right now, you can help in other ways like improving a translation, submitting a bug report, or simply spreading the word.

Thank you so much for your support!

Download the latest ChatSecure version here:

download chatsecure on the app store

Written By
Chris Ballinger

ChatSecure v4.0 - OMEMO and Signal Protocol

ChatSecure v4.0 - OMEMO and Signal Protocol

We’re excited to announce the release of ChatSecure v4.0, our largest step forward in usability since the addition of push messaging six months ago. The most significant new feature is OMEMO Encryption, a mobile-friendly encryption scheme pioneered by Conversations that adapts Signal Protocol to the XMPP world.

Using OTR on mobile has always been problematic because it was designed for desktop computers and synchronous conversations. For example, if you don’t have an active OTR session, you can’t start a new secure session if your contact is offline. Even if you do have an OTR session, it can go stale if one of the sides is purged from RAM due to low memory. This can lead to messages that disappear into the ether with no standardized way for the recipient to indicate which message they couldn’t decrypt.

OMEMO fixes all of these problems, and opens doors to new features that were impossible with OTR, like multi-client support, encrypted group chat, and more reliable file transfers. Multi-client conversations would work particularly well with our planned Desktop client, so we’re excited to add support for these features in future releases.

There are some other major changes in this release that improve the user experience, such as the outgoing message queue and enhanced identity management. The message queue automatically negotiates OMEMO and OTR sessions and allows you to resend messages in case of failure.

Image of Profile View

The new profile view allows you to view a contact’s OMEMO and OTR fingerprints, change each fingerprint’s trust settings, and modify the default encryption method. We’ve made important changes to the way trust is handled for new contacts by adopting the TOFU or “trust on first use” model. The first time you see OMEMO or OTR fingerprints for a contact, they will appear as trusted and marked with “TOFU” in the user interface. Any subsequent fingerprints will be untrusted and need to be manually verified. In this release you can compare fingerprints out-of-band by pressing on the cell and bringing up the system share dialog, but we plan to streamline the fingerprint comparison process in the future.

There are hundreds of other changes under the hood that fix bugs, improve performance, and enhance reliability. On the roadmap for v4.1 and beyond are improvements to group chat, including OMEMO encryption, multi-device chat history synchronization (XEP-0313 MAM), read receipts (aka chat markers XEP-0333), improved file transfer, and more.

We’re excited to see people experience this new frontier for XMPP usability. We will be working with the Zom project to bring OMEMO support to their suite of apps, and we expect other apps will start adopting OMEMO as well.

Thank you to everyone who helped make this release a reality!

Download on the App Store

Download ChatSecure on the App Store

Written By
Chris Ballinger

The End of ChatSecure Android

The End of ChatSecure Android

The developers of the Android version have hard forked the code and are no longer maintaining the upstream version. If you still use ChatSecure Android you should migrate to another app immediately. For a similar user experience and the best compatibility with the latest features of ChatSecure iOS, we recommend downloading Conversations.

The development of ChatSecure iOS is unaffected by this change and we will continue to release new features and updates.

Written By
Chris Ballinger

ChatSecure iOS v3.2.3 - XMPP Push

ChatSecure iOS v3.2.3 - XMPP Push

We’re excited to announce that XMPP push (XEP-0357) is now available, finally allowing users to receive push messages from any contact. This feature is only available when used with compatible XMPP servers, and requires special modules to be enabled for Prosody (mod_cloud_notify) or ejabberd (mod_push).

Our next release will focus on OMEMO support for multi-device asynchronous end-to-end encryption, which will provide huge usability gains over OTR on mobile devices. Thankfully the GPL + App Store licensing issues concerning SignalProtocol have been resolved. You can try OMEMO today in other apps such as Conversations, Gajim, and Cryptocat.

v3.2.3 changes:

  • XMPP push for supported servers (XEP-0357)
  • Improved subscription requests UI
  • Basic vCard nickname support
  • Fix issues with missing messages during stale OTR sessions
  • Improved IPv6 support for NAT64/DNS64
  • Fix some issues with presence/availability
  • Added button to view your password
  • Fix issue where message view would appear multiple times
  • Automatically start OTR sessions when contact is online
  • Send error messages back to contact when messages cannot be decrypted

Download on the App Store.

Written By
Chris Ballinger

ChatSecure iOS v3.2 - Decentralized Interoperable Push Support

ChatSecure iOS v3.2 - Decentralized Interoperable Push Support

With the release of ChatSecure iOS v3.2, we have enabled the first phase of a new form of push messaging that is decentralized, interoperable, and reduces identifiable metadata. Users of any app compatible with the ChatSecure Push protocol can send push messages across app boundaries, starting with the latest release of ChatSecure iOS and the next version of Zom Messenger. These push messages currently contain no content and are simply a way to wake up the receiving client for ~20 seconds.

Unlike centralized messaging applications like WhatsApp, Signal or Telegram, a core part of our mission is to allow users to connect any XMPP server of their choice and to encourge users to run their own servers. This privacy win also comes with a major drawback for iOS users, because Apple prevents the application from running in the background. The only way push messages can be sent are through servers run by app developers themselves, which presents a problem when trying to support push for any arbitrary XMPP server.

Example Flow

Alice ([email protected]) and Bob ([email protected]) are both using the ChatSecure iOS app to communicate via their private XMPP server After each OTR session is established, they each send a payload inside the OTR channel that contains a fresh token and their push API endpoint. The token is used by the API endpoint to lookup your device APNS token, and the endpoint parameter is what allows this to work between apps from different developers. Because all of this data is exchanged by the clients themselves, our push server has no idea about the JIDs of Alice or Bob, or where any of the tokens ended up.

Contact Offline

The next time Alice opens the app and she wants to talk to Bob, she sees that Bob is offline.

Knock Sent

On the chat screen there is now a new button called Knock that has replaced the Send button when the contact is offline (and no text is entered). By pressing Knock, it looks up the token and endpoint that Bob gave her earlier, and sends a HTTP POST to that endpoint with the token.

Contact Online

About 5 seconds later Bob’s client will wake up in the background and automatically login to his XMPP account.

Knock Received

His device will also receive back the token he gave to Alice, do a local lookup to see that the incoming push is coming from Alice, and show a local notification visibile on the lock screen. We are able to keep the app open for about 20 seconds in the background, which is enough time for Alice to establish a new OTR session and send a few messages.

Improving the UX

Having a Knock button is not the ideal user experience because it’s a foreign UI concept and not immediately clear how it works. Originally we tried to automatically trigger knock messages, but hit issues with missing messages caused by sending messages to offline contacts, or when in a stale OTR session. Our message pipeline needs to be reworked to handle these cases and ensure that no message ever enters a black hole.

There is a relatively new way for XMPP servers to interact with app push gateways called XEP-0357 but not very many servers support this extension right now. Our current solution works immediately with any XMPP server as long as you’re both running a ChatSecure Push compatible client. In the future we will roll out client support for XEP-0357 to allow you to receive pushes from any contact, as long as you’re connected to a compatible XMPP server.

The Road Ahead

Although OTR has proven to be trustworthy over the years, it is showing its age in the face of more modern protocols like SignalProtocol (formerly known as Axolotl). Originally we wanted to integrate Axolotl/OMEMO but we haven’t been able to acquire a license from Open Whisper Systems. The next post will be about our plans, in collaboration with the Conversations team, to implement a revision of OMEMO that supports Olm instead of SignalProtocol.

Written By
Chris Ballinger

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