Jami

Free open source end-to-end encrypted peer-to-peer calling and messaging app. It supports video calls, audio, messaging and has a Skype-style interface. It has apps for all major platforms including Android, iPhone/iPad, Linux, Mac and Windows.

Fediverse address:
@Jami@mstdn.io

Cryptomator

Free open source app that lets you add an end-to-end encrypted folder to your existing cloud service. It works with popular cloud services such as Nextcloud, DropBox, Google Drive, One Drive, iCloud etc. There are apps for Linux, Mac, Windows, iPhone/iPad and Android.

Fediverse address:
@cryptomator@mastodon.online

Tutanota

Independent privacy-friendly email and calendar provider which is ad-free and paid for entirely by their users’ subscriptions. There are free open source Tutanota apps for Android, iOS, Linux, Mac and Windows. There’s also support for E2EE and 2FA wherever possible.

Fediverse address:
@Tutanota@mastodon.social

Delta Chat

Free open source end-to-end encrypted messaging system that works through email. This means if you both have Delta apps running you can chat in encrypted mode, but even people without Delta can chat with you through their normal email account. It’s available for Android, iOS, Linux, Mac and Windows.

Fediverse address:
@delta@chaos.social

Briar

Free open source end-to-end encrypted peer-to-peer messaging system for Android and Linux which can be used online through Tor, or locally through wifi or bluetooth. Because it has local support it can be used even if the internet is shut down or broken, for example at demonstrations or in disaster zones.

Fediverse address:
@briar@fosstodon.org