If you don't post suspicious or radical content, even in oppressive regimes there are no problems. This also means that in these regimes using encrypted messages can be suspicious and a very close look from the authorities. In these regimes, then, it is often used to exchange problematic messages through steganography, that is, to hide these messages in innocent images, texts or music that do not arouse suspicion. Some OpenSource apps and services:
- https://stegoshare.sourceforge.net/
- https://www.openstego.com/
- https://steghide.sourceforge.net/
- https://stegcloak.surge.sh/
etc..
There are always manners to show the middle finger to these regimes