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Officially, they only store a hash, but this is only a software restriction - I believe it is possible to obtain full images but this may not be possible with t
by tompccs 7y ago
Officially, they only store a hash, but this is only a software restriction - I believe it is possible to obtain full images but this may not be possible with the public APIs.
In practice it may be possible to reverse-engineer the stored hashes but this has not been demonstrated (yet).
- afandian 7y agoWhat kind of hash is used? I guess it has to be some kind of inexact match (I doubt the fingerprint image is ever exactly the same)? Does it operate over the image of the fingerprint or a vector of extracted features?
- OkGoDoIt 7y agoYeah, I never understood how you could hash fingerprints or face unlock data. How do you do a fuzzy match on a hash? I guess you can make the original data less detailed/precise, such that slight variations would still come out with the same hash, but that seems to defeat some of the security.
- setr 7y agopresumably you would hash many variations of the initial thumbprint, and then simply compare the new thumbprint hash against the list of possibilities, passing upon finding the first match
- lttlrck 7y agoPerhaps it’s similar to how Shazam fingerprints music. It’s a fingerprint of a fingerprint so to speak.
- MiroF 7y agohttps://en.wikipedia.org/wiki/Locality-sensitive_hashing https://en.wikipedia.org/wiki/Locality-sensitive_hashing