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Effective October 28, 2019 Duo Security will be transitioning to Cisco's Privacy Statement. View the Duo Privacy Data Sheet.


No Smartphone? No Problem.

For offline users or those without a smartphone, they can still authenticate with Duo’s phone callback method. Call any phone number enrolled to a user and let them confirm their identity by answering the call and pressing a key.

Administrators can configure the sender’s phone number and specific keys to press to approve and deny authentication and report fraud.

Phone callback is just one of many other two-factor authentication methods that Duo provides to support your diverse user base.

Watch how Duo works with any phone.