Login to drupal with just a number Is it possible to login to Drupal with just a number?

Use case is a kiosk where users have a nfc tag.
So my idea was to hide the input field an use the number retrieved from the nfc tag to identify the users.

The kiosk is only used internally and there would be no keyboard just a touchscreen.

Thanks
You should definitely have a look at the Identification module. Some details (from its project page):

... allows users to login with a custom identification number (or string). To configure this module, the site builder creates a (or specifies a pre-existing) field on the user entity. The value stored in this field for a particular user can then be used as the identification login credential.
Use Case
An organization that wants users to be able to login using a custom identification number and password. This means each user account will have three unique identifiers:

core user name
core user e-mail address
custom user identification number (or string)


Credits (and kudos) to tyler frankenstein!
Note: This answer applies to both D7 and D8.