Yubico Forum

Hi,

My nice white YubiKey has an 8 digit 'serial number' printed on it.

I looked in the manual and it doesn't refer to it, apparently.

Is it unique to my key?

Will I need to make a note of it in case I lose the key?

Martin

That number is the identifier for your key - and is directly related to the first 12 characters of your Yubikey output.

There's a calculator at http://demo.yubico.com/php-yubico/Modhex_Calculator.php that can convert between the "Number" and the "Modhex" output of the first 12 characters. Unfortunately it looks like the Number -> ModHex conversion is broken (or at least, it is for my key), but if you try the other way around it should work.

ie, put the first 12 characters of a one-time password into the string box, select ModHex and "Convert to all formats". The "Number" field returned should match the serial number you're talking about.

The device serial number is a unique number assigned by Yubico at the time of manufacturing and this cannot be changed during the lifetime of the device.

Keys bought on our webstore that works with the Yubicloud authentication service by default have their public id being equal to the device serial number. Howerver, the public ID does not have to be associated with the device serial number if not desired.

Since late 2010, we have marked all Yubikeys with the device serial number together with a two-dimensional barcode (Datamatrix).

The device serial number can be read electronically if this is enabled at configuration:

- Option 1: Allow the serial number to be read via the USB interface via the configuration interface. This option is by default enabled
- Option 2: Include the device serial number in the USB device descriptor (iSerialNumber). This makes the serial number visible through OS API calls
- Option 3: Allow the device serial number to be outputted at startup. Hold the button while inserting the Yubikey. Wait 3 seconds and release.

Best regards,

JakobE
Hardware- and firmware guy @ Yubico