# What I Wish I Knew About U2F and Other Hardware MFA Protocols

DevFeed: [What I Wish I Knew About U2F and Other Hardware MFA Protocols](<https://devfeed.tech/articles/what-i-wish-i-knew-about-u2f-and-other-hardware-mfa-protocols-29953.md>)

Original publisher: [Read original article](<https://goteleport.com/blog/u2f-lessons-learned/>)

Author: info@goteleport.com (Andrew Lytvynov)

Published: 2021-04-15T00:00:00Z

Content type: article

Language: en

Sources: [Teleport](<https://devfeed.tech/sources/teleport.md>)

Topics: [MFA](<https://devfeed.tech/topics/mfa.md>), [Hardware](<https://devfeed.tech/topics/hardware.md>), [Authentication](<https://devfeed.tech/topics/authentication.md>), [Protocol (disambiguation)](<https://devfeed.tech/topics/protocol.md>), [OpenSSH](<https://devfeed.tech/topics/openssh.md>)

Tags: [authentication](<https://devfeed.tech/tags/authentication.md>), [cryptographic](<https://devfeed.tech/tags/cryptographic.md>), [hardware](<https://devfeed.tech/tags/hardware.md>), [mfa](<https://devfeed.tech/tags/mfa.md>), [openssh](<https://devfeed.tech/tags/openssh.md>), [protocols](<https://devfeed.tech/tags/protocols.md>), [usb](<https://devfeed.tech/tags/usb.md>)

## AI overview

This article explains U2F and related hardware MFA protocols, including how U2F devices use challenge-response authentication and verify both possession of the device and user presence. It also describes Teleport 6.0 improvements that allow TOTP and U2F together and support multiple registered devices.

## Source excerpt

We revamped the second-factor authentication in Teleport 6.0. This post provides a birds-eye view of U2F and other cryptographic hardware standards.