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8 Types of Multi-Factor Authentication

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Multi-factor authentication is a process of verifying identity using at least two independent factors including what a person knows, possesses and physical attributes of a person such as their voice. The following are common factors that are used in multi-factor authentication processes.


A numeric password such as a personal identification number (pin).


A user created string of characters.

Challenge / Response

Answers to challenge questions that may include obscure personal information.

Magnetic Stripe Cards

Cards that contain data such as identification numbers written on magnetic storage media. May include other security features such as an employee id card with a photo on the front.

Card Security Codes

Codes that are physically written on a card. Users are asked to input the code to show they are in possession of the card. In some cases, multiple codes are written in a grid and users are asked to enter the code from a particular row and column.

Smart Cards

Cards that have embedded computing capabilities that typically include authentication credentials such as public key certificates.

Security Tokens

Hardware such as a USB device or mobile phone that generate time-synchronized tokens based on a shared key with an authentication service. Such devices may directly interface with authentication services. Alternatively, they may display a time-synchronized one-time password for users to input.


Biometrics such as voice recognition or fingerprint scans.
Overview: Multi-Factor Authentication
Verifying identity using multiple factors including knowledge, possessions and biometrics such as voice.
Also Known As
Two-factor authentication
Three-factor authentication
Related Concepts

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