How many keys will the entire system contain if you choose a symmetric cryptosystem? How many keys will each user need if you choose an asymmetric cryptosystem? How many keys will the entire system...

How many keys will the entire system contain if you choose a symmetric cryptosystem? How many keys will each user need if you choose an asymmetric cryptosystem? How many keys will the entire system contain if you choose an asymmetric cryptosystem? Which system will require less time to add a new user to the cryptosystem? Which system will require less time to remove a user from the cryptosystem?