To use many of the services on the Internet today, such as email, online banking or online shopping, you must first prove you are who you say you are. This process of proving your identity is known as authentication. Authentication is done by using something you know (such as your password), something you have (such as your smartphone), or something unique to you (such as a retinal scan or fingerprint). Traditionally, one of the most common ways of authenticating has been a username and a password. The problem with using just a password for authentication is simple: all an attacker needs to do is guess or compromise your password and they gain instant access to your online account and information. If you use the same username and password for multiple accounts, the harm can be even far greater. To better protect your online accounts, websites are moving to stronger authentication methods that require the use of more than one factor to authenticate. We will explain what this is, how it works and why you should use it.
OUCH! Newsletter for November 2012: http://www.securingthehuman.org/newsletters/ouch/issues/OUCH-201211_en.pdf
The OUCH! newsletter is a monthly security awareness publication by the SANS Securing the Human program.