is a Conditional Access System developed by France Telecom.
allows remote users to communicate safely with their private network through the untrusted public network. A VPN typically uses Internet to establish secure links. Before opening a session, the system authenticates the actors. A user must be registered to a Certification Authority. He usually has a secure token and a PIN for authentification. Then it encrypts all the communication.
is a piece of malware that hides and replicates itself on a computer’s memory. Viruses do spread by their own. They need to be carried through software distribution. Trojan horses and worms may help to spread viruses.