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[Question] Generating the same OTP in two NEOs
https://forum.yubico.com/viewtopic.php?f=26&t=1762		 Page 1 of 1
Author:  RobertoMIT [ Fri Feb 27, 2015 7:35 am ]
Post subject:  [Question] Generating the same OTP in two NEOs
Hello there. I just got two brand new NEOs and started using the Yubikey Authenticator app for Android. I want to be able to retrieve the same set of credentials (e.g. Gmail, facebook, Dropbox) using either one of the NEOs, but so far I have been unable to do so. Any help is welcome. This is what I (think I) know so far:

- The Yubikey Authenticator app is receiving from the NEO, via NFC, a link with the OTP generated by the NEO.
- Each NEO generates a different OTP.

A key question is whether it is possible, by using the Yubikey Personalization Tool, to reprogram one of the NEOs to mimic the behavior of the other.

Another question is whether it is possible to make the app to accept either one of the NEOs to retrieve the same set of credentials (I doubt this is possible.)

Any ideas?

Roberto
Author:  Tom2 [ Fri Feb 27, 2015 11:37 am ]
Post subject:  Re: [Question] Generating the same OTP in two NEOs
Hello Roberto,

I think there is a bit of confusion here. The yubikey supports multiple protocols and you're mixing them up a bit.

OATH protocols such as TOTP, can be used on different device if they have proper clock synced
OATH HOTP, unfortunately is counter based and using one device will make the other out of sync.

Sames goes for the Yubico OTP, which you progamme with the Yubikey personalization tool.

If you want to create a backup device for the the Yubico OTP, save the secrets and use them later on to re-programme you new Yubikey with a higher starting counter value (if ever needed)


However best practice is to simply add both device to your authentication system, one will be acting as a back up. No need to have the same secrets in it.

Tom.
Author:  RobertoMIT [ Fri Feb 27, 2015 6:52 pm ]
Post subject:  Re: [Question] Generating the same OTP in two NEOs
Tom2 wrote:
However best practice is to simply add both device to your authentication system, one will be acting as a back up. No need to have the same secrets in it.


Tom, how can I do this with the Android Yubikey Authenticator? I think it can't, because each one accesses a different sent of credentials. Am I missing something?
Author:  Tom2 [ Mon Mar 02, 2015 4:34 pm ]
Post subject:  Re: [Question] Generating the same OTP in two NEOs
You have a NEO, there are no "slots" the OATH applet can memorize any number of credential (well so far as there is space available)

read https://developers.yubico.com and https://www.yubico.com/products/yubikey-hardware/
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