[liberationtech] iPhone5S Fingerprint and 5th amendment

[Peat Bakke]

> my guess is that fingerprint scanners don't produce the exact same output
every
> time a finger is scanned (similar to what an image scanner might see).
Hash
> functions should produce completely different output if only a single bit
is
> changed, making comparison with a stored value at least a very hard
problem
> if not impossible.

Shifting data from a the sensor would make any bit-for-bit comparison
impossible regardless of hashing, so there is some kind of additional
calculation being done to get to a bit-for-bit comparison.

Vaguely analogous is music recognition software (ala Shazam), which
develops a series of tonal signatures for a piece of music: it's impossible
to recreate the original song from the signatures, but it can still match
with high confidence.

Conjecture conjecture conjecture, of course. Hah. I'm just trying to
consider how fingerprints can be used without the threat of
revealing/reconstructing/hijacking the fingerprint itself ...
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