is password required to extract certs and mac

Hello,

I am newbie.  

Couple questions, please help.

1. Is login password to modem required in order to extract certs and mac? using the tool JTAG and cmnonexpv
2. For a working sub modem, if i extra cert and mac, will this modem become unusable?
3. I see people saying full dump, what is dump? 

Thank you