Two-factor authentication (2FA) and multi-factor authentication (MFA) are indispensable components of the cybersecurity ecosystem. Although one might come to think that the two are synonyms, 2FA and MFA are not entirely the same. Let's clear up the difference between two-factor authentication and multi-factor authentication, as well as questions such as is MFA better than 2FA.
We, as end-users, typically encounter authentication in one out of three forms:
Both 2FA and MFA require a combination of different authentication factors. What are those authentication factors exactly? Within the field of security, there are three factors of authentication that intertwine in cases of 2FA and MFA:
To provide more context about the authentication factors, we'll quickly go through each one individually and give an example for a better understanding.
The knowledge authentication factor, or ''Something the user knows'', is among the most common authentication factor and is usually a plain password or PIN. It is the most common factor within single-factor authentication but is also present within 2FA and MFA. Due to being one of the first forms of authentication, a password in today's cybersecurity environment presents one of the weakest security links. For most experienced hackers, cracking a password is as easy as cracking an egg.
The possession authentication factor usually refers to an HW token, a smart card, or most commonly – a smartphone. Let's say that you need to authenticate an online purchase with an OTP (One-time passcode) sent to your smartphone. With this authentication method, you are presenting possession (the smartphone/mobile phone number on which you received the OTP). OTPs are a popular authentication method for verifying online payments due to their availability through mobile tokens. However, since 2FA and MFA require multiple authentication factors, the amount of friction an OTP carries is not ideal.
The inherence authentication factor relies on biometric authentication based on the user's unique traits. Biometric authentication typically includes either fingerprint or face recognition, as well as location behavior. Since biometrics are hard to spoof, inherence is considered to be the most secure authentication factor of the three. Biometrics are among the favorites in terms of two-factor and multi-factor authentication.
Single-factor authentication requires only one security element, the knowledge one. All of us access our personal and business accounts using some sort of a password. But why do some services prompt us to submit a second authentication factor? Because the owners of those services are aware of the security risks in case a password is the only thing standing between the hacker and company data.
Cybercriminals are equipped with a range of password cracking methods such as keylogging, phishing, and brute force scripts that have high success rates. If plain passwords are your current defense mechanism, it is time to consider 2FA and MFA solutions that fit your organization's needs.
Also, lately, there is a lot of talk about wiping out passwords altogether. Turns out, it's not just talk, it's happening right now. Apple is driving passwords towards extinction by introducing Passkeys, digital keys created by using Touch or Face ID. Considering the incoming passwordless movement, make sure your company is up to date and implement 2FA or MFA that fits your business.
Based on the definitions mentioned earlier, we can now say that 2FA is a subset of MFA. This translates to the following - all 2FA is MFA, but not all MFA is 2FA. Why? The key difference between two-factor authentication (2FA) and multi-factor authentication (MFA) is the fact that 2FA requires explicitly two authentication factors, while MFA demands at least two, if not more, authentication factors as evidence.
The main difference between two-factor authentication (2FA) and multi-factor authentication (MFA) lies in the number of required authentication factors. Two-factor authentication demands exactly two authentication factors to be presented during the authentication process. Multi-factor authentication requires the user to submit two or more authentication factors.
The most correct answer is - it depends. Some would say that the answer is obvious, but for the sake of providing you with the full information, let's elaborate on this one. Every MFA, which includes 2FA as well, is only as secure as the authentication methods used in a particular scenario. Let's put it this way; if you combine three authentication methods such as a PIN (knowledge), OTP (possession), and fingerprint (inherence), you are better off than with a single password. The mentioned MFA approach also beats 2FA which includes, let's say, OTP and Face ID. However, in some cases, two-factor authentication beats multi-factor authentication.
Regardless of the ''missing'' authentication factor 2FA can be more secure in comparison to MFA. In a scenario where 2FA demands authentication factors such as Push Notification (possession) and Fingerprint (inherence), some of the most secure authentication methods out there, the previously mentioned three-factor MFA does not stand a chance. This proves the premise that MFA is only as secure as the authentication methods applied.
Added layers of security result in added friction, right? Not necessarily. The increased use of mobile enables security checks that do not require end-user engagement. If we take location as an inherence factor, the information is extracted without any user intervention. However, to achieve the best results, some friction is necessary. Methods such as Push Notification and Biometrics demand extremely low effort on the end-user side while providing the utmost security standards.
The tradeoff between friction and security can be summed up as follows; Any multi-factor authentication strategy should rely on the lowest friction possible combined with the most secure authentication methods.
5FA, or five-factor authentication, is the extended model which adds two extra authentication factors upon the previously mentioned knowledge, possession, and inherence. The two authentication factors in question are behavior, something the user does/how they do it, and location, where the user is.
Knowledge: Something the user knows (PIN, password)
Possession: Something the user owns/has (token)
Inherence: Something the user is (biometrics)
Behavioral: Something the user does/how they do it
Location: Where the user is
Both of these factors serve as a supporting authentication layer and are not recommended to be used as a primary method of verifying the user's identity. For instance, behavioral authentication is still in its early stages of development, and using it as a single factor of authentication would be a risk. Although it is a promising piece of today's authentication development, the way we hold our phones shouldn't be the deciding factor in whether you gain access to a particular service or not. Location, on the other hand, can be easily spoofed by bad actors by using VPN.
Another reason for low adoption lies in the fact that both of the additional authentication factors are not explicitly a part of any regulation. Knowledge, possession, and inherence are clearly stated as standard authentication factors, while there is no mention of behavioral or location factors.
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