Greetings to all security experts,

I wasn't sure if this was the appropriate place for this thread but figured I could find a few experienced members on this topic. If the mods feel like there is a better place for it please let me know.

I have been searching for encryption tools to securely and privately communicate with people around the world via the internet and smartphones. What I am specifically looking for is encrypted instant messaging, VOIP and smartphone apps that would allow two users to privately exchange text and data across the globe. Since most of these people live in oppressed countries, I would need something that is preferably open source and could provide strong encryption (Like AES 256, ZTRP and etc) to reduce the risk of being exposed by the government.

I have found several options on google but was wondering if anyone has experience using tools like these and suggestions for possible approaches. Also how vulnerable are these tools to attacks and what are the chances of them being cracked if the government would want to listen in or monitor the communications?