Yes, they're both OK. The first can be understood as a refusal to sign anything without first reading it, or as a statement of fact that you have been instructed not to do this. The second is an imperative, so it is an instruction or advice to someone.

I can't sign something without reading it. Never sign something without reading it. That's what I would say, but I think your sentences are fine.

This is forever forever until death to refuse all Asian. However, I don't have nor do I want any responsibility for this country, so don't bother me. Clearly, my man is perpetually, not bitch Taiwanese or any other Asian, don't dream I will have any friendship or relationship with Asian, is not discrimination. Other Asian females I don't know at all. If you continue to ask me a lot or make any voices to pass messages for your bitch rubbish Asian nations, especially from bitch Taiwanese criminal activities without police officers, only attacking me, for my previous Western men for you bitch rubbish Asian females, why don't to die directly and don't close to me a little bit? I don't want to bitch rubbish is female or male. I don't help any one for relationship or friendship, is legal, certainly, I don't have help any one to connect Asian, so to notice me is useless. Are you sure I must die for Asian or anyone becuase I have ne'er fallen in love with any Asian? That is the point to they still notice when I will die becuase I really don't want to marry Asian for personal choice. Still don't say you don't have any beneifts to use me for other social life or anything they want, just sacrifice me directly.

Or You could say..... I can't sign anything without reading it first. Never sign anything that you haven't read first. :-)