The project that Latitude[1] was talking about. I am not saying you are legally obligated to do something (IANAL). I am just saying it is common courtesy.
Trust me. The logo does not make or break your program.
Trust me. The logo does not make or break your program.
Every good logo is trivial in retrospect, it's finding a strong concept that's a bitch. I looked at /gd/ thread and virtually all of it revolves around shaping a keyhole this way or that way. Then suddenly someone says - "Here, done". Turning an empty space into a chat bubble requires a step up, it's an altogether stronger and more complex concept. It is possible that another person came up with it independently, but also consider that with all the variety of secure messaging apps no one had thought of it before 2012. It's not an easy concept to stumble upon.
(edit) This is getting meta. It is plenty obvious that Tox fellas think they are in the clear and it's OK to recycle an existing logo. I think that it's not. That's hard to reconcile.