to keep track the cost spent for every connection made

to keep track of the actions of a user

to require users to prove who they are

to determine which resources a user can access

to provide challenge and response questions

All are correct

store-and-forward

cut-through

fragment free

FCS

continuity

confidentiality

integrity

authentication

availability

nonrepudiation

confidentiality

integrity

privacy

authentication

PKI

a private key

DH

a different public key

a digital certificate