I saw on a movie a man said “Need not to know”. Is this natural and grammatically correct?

Conversation;
-Who… the hell are you?
-Need not to know. I’m just a elementary school student.

Question

I saw on a movie a man said “Need not to know”. Is this natural and grammatically correct?

Conversation; 
-Who… the hell are you?
-Need not to know. I’m just a elementary school student.

Answer

No. It's not a grammatically correct sentence, and it doesn't sound like natural speech.

Answer

expression should be "no need to know (that)".