@veronika cool, glad you got some good proposals! 
Some feedback based on the short description you gave:
“Enough” is an innovative tool for journalists to communicate with their sources via encrypted technology.
- For 1 and 2 I’m not really sure what the icon is supposed to be. It doesn’t communicate security or encryption, or is an E/e. Just looks a bit like a boat?
- 3 is quite simple, but also a bit basic.
- The one with the OU connected as a locked chain is the best one I would say. If you want to go a step further you could slightly adjust it to make the communication aspect more obvious:
And the icon only would then be:
