For the posters such as EstellaHanclay accusing @saubbs of being selfish, first, I do understand at lease second hand how much it can hurt to not know one's father, because that happened to someone who is very, very close to me. I have seen the lifelong damage that can cause, and I am sorry you had to experience that.
However, I think it might be more helpful to the child if we all accept that right now, the OP is facing a dilemma. She actually posted here in the first place because she is trying to work out what is the right thing to do for her DD right now, and she is asking for support and advice on this forum.
I agree with you that the best for her DD would probably be if OP can find a way to let the father know, while also keeping her safe, because if he does know, then there is at least some chance for DD to have a healthy relationship with him.
However, in part from reading all the other stories on here about the behaviour of some males, I also understand the concerns about handing over power and possibly unsupervised access to her DD to a man whom she does not know well, and who might be very angry at OP for having given birth to his child without telling him and without giving him an opportunity to apply pressure to terminate the pregnancy, which he might well have done had he known about it. To be clear, I am not saying she should have done anything differently: his major decision point was when he chose to have sex with OP, and after that, it was her body, her choice. But, however he may now feel about this birth and this child is a reality that will have consequences for DD.
Perhaps a solicitor would be one good source of advice around how best to protect DD, and otherwise, I think OP is looking for advice about how to let the father know in order to give her DD the best chance of being accepted emotionally by him.