We require all candidates who take a Filtered interview to authenticate using LinkedIn, GitHub, or one of several other trusted resources. This is a standard practice which helps us confirm your identity and helps the hiring company have confidence in their candidates.
On interview submission, the hiring company will be able to view your connected account (for example, the manager at that company will be given a link to the candidate's LinkedIn profile).
We assume that most candidates for technical roles have one of these accounts. At the moment, there is no way to submit your Filtered interview without confirming one of these accounts.
In the case that you don't have any of these accounts, we recommend that you create one (preferably LinkedIn) and add your avatar and work history to that account to the best of your ability.
If all else fails, please contact your recruiter.