Can my best friend be the legal father of my baby though he is not the biological dad?

I'm 18 and pregnant. I'm only 12 weeks but the biological father is not involved and doesn't want to be involved. My best friend has offered to claim the baby completely. I've never been married and have been emotionally attached to my best friend for a very long time where the father of the baby was just a 3 month high school boyfriend. My best friend and I have talked to the bio father and he agrees and would prefer that my best friend claim the baby and sign the certificate. We are all in agreement that the best friend should raise the baby with me including the bio father. Is this okay? I don't want anyone to ever know who the real father is we have told everyone is the father. If he claims it and the bio father never fights it is there any issue? If there is a problem, could the bio father explain that he knows what was going on and he agrees with it and it all be handled without any family ever knowing. We live in indiana. Everyone involved agrees we just do not want to go through all the legal stuff. He is willing to sign the papers and be the father completely and the bio father is willing to let him claim the baby.