The glossary below contains many of the terms you will find in common use throughout our website. Please refer to this list to find definitions of terms and answers to other Internet security-related questions.

two-factor authentication

A type of authentication that is based on something a user knows (factor one) plus something the user has (factor two). In order to access a network, the user must have both factors (in the same way that a user must have an ATM card and a personal identification number [PIN] to retrieve money from a bank account). In order to be authenticated during the challenge/response process, the user must have this specific (private) information.