usernames and passwords
secure password to minimise chances of unauthorized users accessing should contain letter different punctuation and numbers and should be at least 8
anti malware
scans a system and removes viruses.
left to infect a system a virus could delete data
firewall
prevent unauthorized packets from a network to access
encryption
conversion of data into unreadable format so it cannot be understood if intercepted
permissions
is the creation of different levels of file access so that only authorized people can access and change certain files.