Password Security 101
Two Factor Authentication
Layered Authentication
Two Factor Authentication refers to a second layer of authentication which is required to access a system. This method protects sensitive data and systems when a single factor has been compromised. Most of the time, one factor will consist of something you know and the other factor will consist of something you have. It is not uncommon, but less desirable to use two things you know. Due to possible loss or theft, using only two things you have is not desirable at all, except, of course, in the case of biometrics!
Some examples of things you might know (challenge-response authentication):
- a password
- a bank PIN
- your mother's maiden name (this one is getting worn out)
- the name of your first school
- a one time password from a list (use once, cross out)
The latter example might be considered something your have, but your must know it to enter it. Portable devices are also used for this purpose.
Some examples of things you might have (token authentication):
- a proximity card
- a bank card
- a USB key
- a private encryption key on a disk drive
- your fingerprint
- your iris
The latter two are examples of biometrics, increasingly common in use for authentication as well as identification purposes.
In addition to things you have and things you know, other factors can be layered on top of these. Some examples:
- the time of day
- a telephone callback system
- the IP number of your computer
With the epidemic of online fraudulent activities, such as phishing scams, we must all get used to the additional burdens of multiple layers of security.
A Two Factor Fable
The Wolf, The Goat and The Kid
As an old Goat was going forth to pasture, she carefully latched
her door, and bid her kid not to open it to anyone who could not
give this password: Beware of the Wolf and all his race.
A Wolf
happened to be passing, and overheard what the old Goat had said.
When she was gone, he went to the door, and, knocking, said:
"Beware of the Wolf and all his race." But the Kid, peeping through
a crack, said: "Show me a white paw and I will open the door." As
the Wolf could not do this, he had to depart, no better than he
came.
Moral: Two sureties are better than one.
Aesop, 620 - 560 B.C.
Aesop's Fables
Litscape.com -- Classic Literature Online
Link To This Page
Knowledge is power. The Bitmill Inc. encourages links to our site. To link to this page, please cut and paste the following HTML code into your web page source file.
<a href="http://www.thebitmill.com/articles/password_twofactor.html">Two Factor Authentication</a>
Your link will look like this:
Two Factor Authentication
Thank you for your interest and support.
