Can I refuse a paternity and get all rights to my child?

I am a 22 year old mother to a 3 month old boy. the believed father and I were never in a relationship at any time what so ever. he was my brothers friend and we were all hanging out and had a drunken night. might sound terrible but it happens. I love my son with every bone in my body. besides the point he had put his hands on me shorty after because i refused a relationship with him and is known for getting into fights at bars and also has a terrible record of drugs and other felonies. he was in jail for most of the pregnancy and when he was around he threatend me because i didnt want him around and was trying to leave the state for a better life. i never had him involved in any of the dr appointments nor did i put his name on any papers. ever. i do not trust him or his family with my child. i recently got a letter in the mail saying he wants a paternity test i guess so he can prove its his so he can get his rights. i dont want him to have any rights and i want to make this as hard as possible for him so i can keep my child out of harms way. he doesnt deserve to be around my son and i want to gain all of rights possible to raise my son healthy and happy. i need to know what i can do legally to keep him from getting any kind of custody. WHAT ARE MY RIGHTS?? can i refuse a paternity and how hard can i make it for him so eventually he will give up and let me and my son be??