Biometric authentications

Authentications that app supports

1. BIOMETRIC_STRONG (a.k.a Class 3)
2. BIOMETRIC_WEAK (a.k.a Class 2)
3. DEVICE_CREDENTIAL (a.k.a Class 1)
   • PIN
   • Pattern
   • Password

Notes on Biometrics

First there are some metrics to understand:

• Spoof Acceptance Rate (SAR): Previously recorded sample got accepted.
• Imposter Acceptance Rate (IAR): A mimicked sample got accepted.
• False Acceptance Rate (FAR): An irrelevant sample got accepted.
• False Reject Rate (FRR): The chance of correct sample didn’t get accepted.

BIOMETRIC_STRONG or Class 3

• SAR: 0-7%
• FAR: 1/50k
• FRR: 10%

BIOMETRIC_WEAK or Class 2

• SAR: 7-20%
• FAR: 1/50k
• FRR: 10%

DEVICE_CREDENTIAL or Class 1

• SAR: >20%
• FAR: 1/50k
• FRR: 10%

One more interesting thing

The category of a certain biometric isn’t solely determined by its type. e.g. Face or Iris. Pixel 4 and Pixel 7 both support face biometric. However Pixel 4’s face biometric is considered as class 3 while Pixel 7’s is class 2. (Note: They have different implementations)

You can find this proof on https://support.google.com/pixelphone/answer/9517039.