Overview

Multi-factor authentication (MFA) provides an additional layer of security that helps ensure that the accounts of your users can't be easily compromised by malicious actors.

Nowadays, many of the passwords in use can be easily compromised because:

• They are re-used across multiple websites and applications.
• They were leaked to the web and sold to malicious actors.
• They are considered "weak" because they are short, have obvious, derivable patterns, or contain easy-to-guess character strings.

By enabling two-factor authentication in your project, you introduce an additional verification step that can protect user login or self-service actions, such as updating account information or credentials, from malicious actors.
For example, you might decide to require a user to log in with two factors right at the start of the session. Alternatively, you could allow the user to start the session by logging in with the first factor and only require the second factor at the point where the user is about to perform a security-sensitive operation. Read more about dynamic MFA in the step-up authentication document.

Available methods

Ory offers multiple second-factor authentication methods:

Time-based one-time password (TOTP)

Time-based one time passwords (TOTP) are a flexible 2FA authentication method based on a shared secret, and can be used both with browser-based apps and native apps. Read Time-based one-time passwords (TOTP) to learn more.

WebAuthn

This method uses the Web Authentication API, also known as WebAuthn, which allows servers to register and authenticate users using public-key cryptography. Read WebAuthn and FIDO2 (YubiKey) to learn more.

Lookup Secrets

Lookup Secrets, also known as Backup Codes or Recovery Codes, are a 2FA fail-safe mechanism, rather than a standalone two-factor authentication method. They can be used to complete the second factor when users lose access to their selected 2FA method. Read Lookup Secrets (Recovery Codes) to learn more.

SMS

SMS for MFA sends a one-time password to the user's registered mobile phone number via text message. Read the Code via SMS documentation to learn more.

Terminology

Learn more about the terms and concepts used when talking about 2FA in Ory.

Authentication Method Reference (AMR)

The Authentication Method Reference (AMR) is an array of authentication methods used over the lifetime of an Ory Session.

The following methods can be present in a session:

• password - When the user authenticated with their password.
• oidc- When the user authenticated by signing in with a social sign-in provider.
• totp- When the user authenticated by entering a time-based one-time password.
• webauthn - When the user authenticated through a WebAuthn channel, such as OS-level biometric authentication or a hardware token.
• lookup_secret - When the user entered a valid one-time recovery code.

This is how the information is presented in the Ory Session when you fetch the session from the Ory Identities API:

Sample Ory Session JSON payload

{
  id: "6b51a3f2-6a2c-4557-90a8-4e23de7072aa",
  active: true,
  // ...
  authenticator_assurance_level: "aal2",
  authentication_methods: [
    {
      method: "password",
      completed_at: "2021-10-14T09:37:53.872104Z",
    },
    {
      method: "totp",
      completed_at: "2021-10-14T09:41:16.771859Z",
    },
  ],
  // ...
}

If a user authenticates multiple times over the lifetime of the same session with the same method, every successful attempt will be present in the session:

Sample Ory Session JSON Payload

{
  id: "6b51a3f2-6a2c-4557-90a8-4e23de7072aa",
  active: true,
  // ...
  authenticator_assurance_level: "aal2",
  authentication_methods: [
    {
      method: "password",
      completed_at: "2021-10-14T09:37:53.872104Z",
    },
    {
      method: "lookup_secret",
      completed_at: "2021-10-14T09:41:16.771859Z",
    },
    {
      method: "password",
      completed_at: "2021-10-14T12:00:00.134567Z",
    },
  ],
  // ...
}

Authenticator Assurance Level (AAL)

The Authenticator Assurance Level (AAL) indicates how many authentication factors the identity has completed.

Authentication methods are classified into factors:

Authentication method	Factor
password	first
oidc	first
totp	second
webauthn	second
lookup_secret	second

info

When you enable passwordless authentication with WebAuthn, WebAuthn is not considered as a second authentication factor.

The AAL parameter can take one of two values:

• aal1: The user completed only the first authentication factor(s).
• aal2: The user completed the first and the second authentication factor(s).

danger

Completing two first authentication factors doesn't give the user aal2. For example, logging in with a password and oidc is still aal1.