There are many secure open source applications you can choose from. Kahla is one such messenger.
Kahla is not owned by any corporation. The messenger will not display ads. No one, including the owners of Kahla, will read your messages.
It is completely free, so it’s a great option if you want an app that doesn’t charge you money for texting. Kahla also supports opening in a browser without installation.
The app supports one-to-one conversations, group chats, attaching photos. It also has all the other features you’d expect from an app like this: themes, emoticons, read receipts, and so on.
Kahla is completely open-source, peer-reviewed, and not affiliated with any major technology company. Best of all, it allows you to securely exchange data over the Internet using a strong end-to-end encryption protocol.
All messages, group chats, transferred files, photos, voice calls and video calls in Kahla are securely encrypted. The participants in the conversation can only see them. Encryption occurs without the participation of servers, according to the E2EE principle – from device to device.
Kahla uses so-called secure enclaves — completely isolated storage deployed on the company’s servers, to which even the server owners do not have access.
Thanks to them, you can find out which of your friends uses Kahla without disclosing information from the phone’s address book to the developers. Nobody but you will see the content of the request.