Multi-Factor Authentication

One of the largest problems with traditional user ID and password login is the need to maintain a password database. Whether encrypted or not, if the database is captured it provides an attacker with a source to verify his guesses at speeds limited only by his hardware resources. Given enough time, a captured password database will fall.

As processing speeds of CPUs have increased, brute force attacks have become a real threat. Further developments like GPGPU password cracking, rainbow tables and now the Quantum computers have provided greater advantages for the attackers. GPGPU cracking, for example, can produce more than 500,000,000 passwords per second, even on lower end gaming hardware. Depending on the particular software, rainbow tables can be used to crack 14-character alphanumeric passwords in about 160 seconds. Recently, a paper released by Google’s researchers that was briefly posted on a Nasa’s website before being removed, claimed that their processor was able to perform a calculation in three minutes and 20 seconds that would take today’s most advanced classical computer, known as Summit, approximately 10,000 years. With these capabilities, a password database alone doesn’t stand a chance against such methods when it is a real target of interest.

In the past, MFA systems typically relied upon two-factor authentication. Increasingly, vendors are using the label “multifactor” to describe any authentication scheme that requires more than one identity credential.
Authentication factors

An authentication factor is a category of credential used for identity verification. For MFA, each additional factor is intended to increase the assurance that an entity involved in some kind of communication or requesting access to some system is who, or what, they are declared to be. The five most common categories are often described as something you know (the knowledge factor), something you have (the possession factor), something you are (the inherence factor), somewhere you are (location factor) and something you do (Time factors).

More Info: what jobs can i get with a+ certification