Authentication methods in Microsoft Entra ID - OATH tokens
OATH TOTP (Time-based One Time Password) is an open standard that specifies how one-time password (OTP) codes are generated. OATH TOTP can be implemented using either software or hardware to generate the codes. Microsoft Entra ID doesn't support OATH HOTP, a different code generation standard.
OATH software tokens
Software OATH tokens are typically applications such as the Microsoft Authenticator app and other authenticator apps. Microsoft Entra ID generates the secret key, or seed, that's input into the app and used to generate each OTP.
The Authenticator app automatically generates codes when set up to do push notifications so a user has a backup even if their device doesn't have connectivity. Third-party applications that use OATH TOTP to generate codes can also be used.
Some OATH TOTP hardware tokens are programmable, meaning they don't come with a secret key or seed pre-programmed. These programmable hardware tokens can be set up using the secret key or seed obtained from the software token setup flow. Customers can purchase these tokens from the vendor of their choice and use the secret key or seed in their vendor's setup process.
OATH hardware tokens (Preview)
Microsoft Entra ID supports the use of OATH-TOTP SHA-1 tokens that refresh codes every 30 or 60 seconds. Customers can purchase these tokens from the vendor of their choice. Hardware OATH tokens are available for users with a Microsoft Entra ID P1 or P2 license.
The preview is only supported in Azure Global and Azure Government clouds.
OATH TOTP hardware tokens typically come with a secret key, or seed, pre-programmed in the token. These keys must be input into Microsoft Entra ID as described in the following steps. Secret keys are limited to 128 characters, which may not be compatible with all tokens. The secret key can only contain the characters a-z or A-Z and digits 2-7, and must be encoded in Base32.
Programmable OATH TOTP hardware tokens that can be reseeded can also be set up with Microsoft Entra ID in the software token setup flow.
Once tokens are acquired they must be uploaded in a comma-separated values (CSV) file format including the UPN, serial number, secret key, time interval, manufacturer, and model, as shown in the following example:
upn,serial number,secret key,time interval,manufacturer,model Helga@contoso.com,1234567,2234567abcdef2234567abcdef,60,Contoso,HardwareKey
Make sure you include the header row in your CSV file.
Once properly formatted as a CSV file, a Global Administrator can then sign in to the Microsoft Entra admin center, navigate to Protection > Multifactor authentication > OATH tokens, and upload the resulting CSV file.
Depending on the size of the CSV file, it may take a few minutes to process. Select the Refresh button to get the current status. If there are any errors in the file, you can download a CSV file that lists any errors for you to resolve. The field names in the downloaded CSV file are different than the uploaded version.
Once any errors have been addressed, the administrator then can activate each key by selecting Activate for the token and entering the OTP displayed on the token. You can activate a maximum of 200 OATH tokens every 5 minutes.
Users may have a combination of up to five OATH hardware tokens or authenticator applications, such as the Microsoft Authenticator app, configured for use at any time. Hardware OATH tokens cannot be assigned to guest users in the resource tenant.
Make sure to only assign each token to a single user. In the future, support for the assignment of a single token to multiple users will stop to prevent a security risk.
Determine OATH token registration type in mysecurityinfo
Users can manage and add OATH token registrations by accessing https://aka.ms/mysecurityinfo or by selecting Security info from My Account. Specific icons are used to differentiate whether the OATH token registration is hardware or software based.
|OATH token registration type||Icon|
|OATH software token|
|OATH hardware token|