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I don't like the word "impossible" so let's leave that by the sidelines. Impractical is a word I prefer. The reason it is impractical is firstly it is lossy no

I don't like the word "impossible" so let's leave that by the sidelines. Impractical is a word I prefer. The reason it is impractical is firstly it is lossy not lossless data storage meaning that when your fingerprint is scanned a whole ton of information is discarded immediately and then the fingerprint is normalised which discards yet more still before being stored. So the resulting data stored literally doesn't contain the same level of information as a "real" human fingerprint, and as a result of that the data might be useful in recreating a simulated fingerprint which can beat Apple's TouchID but it would likely still be incompatible with most other fingerprint systems and databases, and the fingerprint you recreated from the data likely wouldn't look like your "real" fingerprint as several million different fingerprints can result in the same lossy compressed representation stored in the phone. Imagine it like taking a photograph and then using a JPG compressor to decrease that photograph's size by 80% an then trying to get back the original photograph from the compressed JPG. While you can certainly get close it is implausible that you'd ever get the original image back and even if you did get it back there is no way to verify that the "original" you recreated was the same as the actual original without the actual original to compare it to.

gren 13y ago
Thanks for your comment :) So eventually, if you can generate all possible set of fingerprints which match that hash and "cross check" it with another fingerprint systems, you could be able to approach the guy fingerprint? (I mean you maybe reduce the set to a reasonable size) The use case is quite overkill though! Also, generating all possible set of fingerprints is probably a lot of computation.
- UnoriginalGuy 13y ago
  The other fingerprint system would need to be compatible with your data source, but if you had a compatible system and if you could generate every potential fingerprint for a given hash you could definitely use cross-checking to find any individual in your several million who also happens to be in the database. I think the biggest potential problem with that approach is both incompatibility and also false-positives. You might have "too many" matches for it to be useful for much.

gren 13y ago

Thanks for your comment :) So eventually, if you can generate all possible set of fingerprints which match that hash and "cross check" it with another fingerprint systems, you could be able to approach the guy fingerprint? (I mean you maybe reduce the set to a reasonable size) The use case is quite overkill though! Also, generating all possible set of fingerprints is probably a lot of computation.

UnoriginalGuy 13y ago
The other fingerprint system would need to be compatible with your data source, but if you had a compatible system and if you could generate every potential fingerprint for a given hash you could definitely use cross-checking to find any individual in your several million who also happens to be in the database. I think the biggest potential problem with that approach is both incompatibility and also false-positives. You might have "too many" matches for it to be useful for much.