How to quickly establish secure chats with QR codes

Delta Chat has a QR-code based mechanism for inviting people to a chat, without needing to first exchange phone numbers or e-mail addresses. You can use it to establish one-on-one chats or to let people join a group.

This HOWTO first explains how to scan QR codes on Android and Desktop, and then shows how to create QR codes for yourself or for a group chat. You can find it here:

We hope it’s helpful and would be happy to get your feedback. There is also - slightly hidden - a Feedback group in the Howto, can you find it? If yes, please join if you have questions or remarks! Have fun with scanning and chatting! :slight_smile:


I’m still unsure about the whole interaction between printing and verify-contact. The story of printing QR codes seems like it is more or less established practice, but intuitively to me it breaks verify-contact as now Alice (who’s business card it is) will have Bob marked as verified, but really anyone could have scanned the QR code as it was left on the train. So whoever gets this card first effectively gets to MITM Bob if they are dedicated enough about it.

On an entirely different aspect of printing, the printing section only says “you could do this” but doesn’t explain how you get the QR code from your device onto paper (via pdf? some other way?).

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good point Flub! I am working on a revision of the howto and will include this. We tried to express the problem with the verification when you print a QR code, but maybe it wasn’t clear enough.

Hi Flores, I updated the How To incorporating your feedback and other peoples feedback, the new version can be found under the same link:
Thanks everyone for contributing and feedbacking!