One key problem with biometrics is that they are permanent.
The much maligned password is less secure than using a unique biological marker to identify yourself, but it can be changed if it is leaked or compromised in some way. Your fingerprints, on the other hand, are yours forever.
And the immutable nature of the fingerprints becomes even more concerning when you consider how public they can be. You leave prints out in the world just going through your day -- and Krisller shows data needed to fake the prints can also be captured remotely without direct contact.
"Biometrics are not secrets," American Civil Liberties Union analyst Jay Stanley explained to The Washington Post earlier this year.
As fingerprint scanners become more and more common, they are also raising legal questions. At least one court has ruled that police could compel a suspect to give up his fingerprint, but not his passcode, in order to unlock and search his cellphone.