I've recently imported a private key into the client on a livecd offline computer. I used bitaddress.org to generate an address and private key. I sent some bitcoin to my address and wanted to make sure I could access them with the private key bitaddress.org gave me.
It worked and I verified that my address was in there and the private key works however I have some concern after a few quesstions I asked before and what I read on the wiki about importing private keys.
WARNING
Before reading this page, users should note that messing with ECDSA private keys is very dangerous and can result in losing bitcoins, even long after the import. It is recommended that outside of self-generated vanity addresses, users should never import (or export) private keys
What does this mean? this is at the wiki. Some other user tried to explain it but I couldnt quite understand and didn't get any answers off anyone else.
Question number 2:
I then came across this message:
Because bitcoins can only be spent once, when they are spent using a private key, the private key becomes worthless. It is often possible, but inadvisable and insecure, to use the address implemented by the private key again, in which case the same private key would be reused.
What does this mean? I've imported the private key just to verify....but I'm wondering if I can recieve bitcoins in the future and also send any transactions when I need to.
I'm a little concerned about the warnings and want to reassure myself
thanks for your patience.