Many kinds of remote access tasks are performed over the Internet. In some cases, the transmitted data has no privacy requirements, for example when a user accesses a public Web service. However, an increasing number of remote access tasks involve the exchange of confidential data over unsecured TCP/IP networks. A typical remote access task where confidentiality of the data and authentication of the user are highly desired is business e-mail.

The core communication protocols used on the Internet do not natively provide confidentiality for data. Security services are thus deployed to protect the transmitted data from monitoring and modification by unauthorized parties. Security services eliminate many threats that exist on the Internet.