What to Choose: Multi-Factor Authentication or Single Sign-on?

Rising incidents of security and data breach, owing to heavy reliance on single-factor authentication, i.e. password-based authentication only, led organizations to think about and enhance the security of their valuable assets using better and stronger security solutions. When it comes to improving and upgrading the security of systems and applications, the two names that instantly pop-up in our mind are Multi-factor authentication(MFA) and Single sign-on (SSO). Which of these would be better to provide guaranteed and reliable security, is what we will be discussing here.

Multi-Factor Authentication

Multi-factor authentication refers to integrated multiple authentication layers to verify and validate the user’s authenticity, multiple times during a login attempt. A user needs to go through multiple authentications to prove his/her credibility. Each authentication layer would have different elements and attributes to evaluate the credibility of a user.

Initial authentication usually involves checking of user’s registered credentials, i.e. username/email-id and password. Password-based authentication signifies “something a user knows”.
Initial authentication may be followed by the second layer of authentication by verifying a hardware or software token unique to the user. This authentication layer imparts “something a user has”. The complete process may be termed as two-factor authentication.

Second layer authentication check could be followed by the third level of authentication check (three-factor authentication), where a user needs to authenticate him/herself through inherence factors or biological traits, i.e. “something a user is”, e.g. the fingerprint, voice, or retina scan. Similarly, more authentication layers may be implemented using different elements and attributes, resulting in stronger security.

In layman’s language, it may be stated that in multi-factor authentication, solely password would not be the only factor of authentication. A user needs to provide some more inputs besides password to validate his/her identity. Thus, multi-factor authentication has proven to be a security solution that helps in restricting and blocking unauthorized and illegal access from malicious users. Two-factor authentication (2FA) is one of the easiest, simplest, and widely used multi-factor authentication methods, which most organizations are implementing or willing to adopt.

Single Sign-On

As the name suggests, single sign-on (SSO) requires the user to sign-in only once and gain access to multiple applications and services. Single sign-on leverages users to perform a master sign-in, authenticate the user’s credentials, and store it to perform logins later on the user’s behalf to other inter-connected yet independent application & systems, within a certain domain or network boundary.

SSO solution internally stores the user’s credential and uses it in a different manner to log in and access other applications, at each login. This avoids and saves user efforts in authenticating each time before accessing multiple system and applications. Similar to single sign-on, a single sign-out logs-out the user and terminates access to all interconnected applications and systems.

The greatest and may be the only advantage of using Single Sign-on from a security perspective is that it avoids and reduces the risk involved in accessing a third-party website, where user’s credential needs to be used or managed externally.

From the above discussion, it may be inferred that the SSO is a more user-friendly but less security-centered authentication solution whereas MFA ensures fullest protection with multiple & unique authentication layers. A better approach would be the usage of both SSO & MFA (or 2FA), to deliver guaranteed security and better user-experience, simultaneously.