  Prior research states that frequencies below 75 Hz in eye-tracking data
represent the primary eye movement termed ``signal'' while those above 75 Hz
are deemed ``noise''. This study examines the biometric significance of this
signal-noise distinction and its privacy implications. There are important
individual differences in a person's eye movement, which lead to reliable
biometric performance in the ``signal'' part. Despite minimal eye-movement
information in the ``noise'' recordings, there might be significant individual
differences. Our results confirm the ``signal'' predominantly contains
identity-specific information, yet the ``noise'' also possesses unexpected
identity-specific data. This consistency holds for both short-(approx. 20 min)
and long-term (approx. 1 year) biometric evaluations. Understanding the
location of identity data within the eye movement spectrum is essential for
privacy preservation.
