WhatsApp Back Up Restoration

I'm trying to restore my WhatsApp chat history, and it's asking for a encryption code or a password, I don't have a encryption code, and when I try to login with a password it's saying "Your account is not associated with a password. Please enter your 64-digit encryption key instead. Now what possibilities do I have to restore my backup? or is there a way to restore a older backup where end to end encryption was not activated or simply as I say older version of the back up?