2FA vs SSO: Comparing Multi-Factor and Single Sign-On Authentication

As organisations operate across more systems, both in the cloud and on-premises, managing user authentication and access has become increasingly complex. For IT and security teams, balancing convenience with strong protection is critical.

Two prominent methods used to enhance login security while improving the user experience are two-factor authentication (2FA) and single sign-on (SSO). Both aim to simplify how employees, contractors and partners sign in.

Beyond passwords, 2FA offers an additional degree of identity verification. It helps reduce account takeovers, even if credentials are compromised. By offering a centralised access point, SSO enables users to log in just once and effortlessly access all approved web applications and internal systems using a single set of login credentials.

While both 2FA and SSO streamline user authentication, they take different technical approaches. This article examines the core differences between these solutions from a business perspective. It analyzes considerations like access control, system integration requirements, deployment scalability and security capabilities.

The objective is to assist organisations in determining which identity federation or multi-factor approach best suits their particular needs for authorization and authentication in light of their business objectives, IT environment, and risk profile. Making the right choice supports secure, productive digital workflows.

What is SSO?

Single sign-on (SSO) allows a user to securely access multiple applications, systems, and websites using a single set of login credentials. With SSO, once authenticated for one application, the user gains access to all others within the organization's portal without re-entering credentials repeatedly.

Some key aspects of SSO include:

  • Centralised authentication: Users log in at a single portal using one username and password to be verified.

  • Federated access: The credentials are then "federated" or shared with other linked applications via integration with an SSO protocol.

  • Common protocols: Popular protocols for facilitating SSO include SAML, OpenID Connect, OAuth, and Kerberos. These allow apps to exchange authentication and authorization data in a standardised way.

  • Seamless experience: After initial login, a user is automatically signed into their permitted systems behind the scenes without additional prompts when switching between sites.

  • Simplified password management: Users only need to remember their SSO credentials rather than unique login details for every individual application.

SSO centralises access management and user authentication, alleviating the strain on help desks from forgotten passwords and enabling uniform security policy enforcement across all integrations.

​​How Does Single Sign-On Work?

SSO relies on a centralised identity provider (IdP) that authenticates a user's credentials once and then shares this authentication with other connected service providers (SP). Here are the typical steps:

1- Authentication

A user enters their username and password on the IdP login page to be authenticated. The IdP verifies credentials against the identity store (e.g. Active Directory).

2- Security Token Exchange

Upon successful login, the IdP passes a signed security token with the user's identity details to the SP. This token is cryptographically secure and can be time-limited.

3- Authorization Check

The SP presents the token to the IdP to verify the user's identity and check permissions. The IdP confirms access is allowed based on pre-defined authorization rules.

4- Access Service

If authorised, the user is seamlessly signed into the SP, which relies on the security token for the user's identification rather than requiring new credentials.

5- Single Logout

A single sign-out triggers all connected sessions at once, like clicking "logout" closes all open application instances the user was signed into.

This centralised authentication model allows services to trust each other through standards like SAML and OpenID Connect while presenting a unified sign-on experience to users.

How do you choose Single sign-on solutions? 

When choosing an SSO solution, consider factors like business needs, login options, and popular providers.

Some top SSO solutions to evaluate include Azure Active Directory (Azure AD) and Okta.

  • Azure AD leverages SAML for secure authentication between identity and service providers. It seamlessly integrates with Microsoft Azure.

  • Okta is a full identity platform that offers centralised user management and supports protocols like SAML, OAuth and OpenID Connect.

Both provide important SSO benefits like passwordless login and access control. Azure AD is best suited for organisations heavily using Microsoft. Okta offers flexibility for multi-platform apps.

Whichever option you select, SSO simplifies identity management and reduces the number of passwords while improving security and user experience. Evaluate solutions based on technical and business requirements.

Differences between 2FA and SSO

While both 2FA and SSO aim to strengthen user authentication, there are important distinctions in their implementation and capabilities:

Authentication vs Authorization
2FA verifies the identity of an individual user through a secondary check. SSO provides a method for distributed authorization, controlling what accounts and systems a verified user can access within a session.

Granularity of Access Control
2FA is applied on a per-account basis, authenticating the user separately for each system they log into. SSO enables fine-grained access policies to determine which specific applications a user receives single sign-on access to. This allows the distribution of permissions at a more granular level than 2FA.

Centralised Management
SSO centralises identity management, credential storage, and access rule configuration. 2FA does not include a centralised point of control, so authentication policies must be set independently for each application. SSO simplifies user provisioning and governance.

Implementation Flexibility
While 2FA is backwards compatible, SSO requires compatible applications and defined trust relationships between identity providers and service providers. 2FA can be more easily added to existing infrastructure.

The key difference lies in 2FA focusing on the individual authentication act versus SSO facilitating authorization through mediated access across multiple systems.

Daito 2FA Mobile


In today's dispersed digital ecosystem, balancing security and usability when authenticating users to multiple systems is critical. Both 2FA and SSO provide important layers of protection beyond basic credentials.

For individual account access, 2FA enforcement delivers a strong defence against unauthorised logins, even if passwords are lost or stolen. It works independently of existing infrastructure but requires per-account configuration.

SSO centralises identity management and introduces a higher level of access control granularity through federated single sign-on. This streamlines user onboarding and navigation across business applications. However, it demands integration standards between the identity source and connected services.

Ultimately, the best approach combines both methods - using 2FA as the first authentication factor for high-risk accounts and then SSO for seamless intra-organization access once validated. Or leveraging a shared 2FA solution like Daito that works across multiple apps similar to SSO.