Android 6.0 ha introdotto molte novità a livello di codice nativo e, tra le più importanti, troviamo il supporto al lettore di impronte digitali – implementato per la prima volta da Big G sulla nuova line up Nexus 6P e Nexus 5X. Come noto, questi sono presenti sugli smartphone Android già da molto tempo ma con Marshmallow sono supportati ufficialmente anche da Google.
Attraverso l’Android 6.0 Compatibility Definition Document, Google elenca una serie regole di conformità circa questa specifica hardware. L’obbiettivo? Semplice: gli OEM dovranno implementare sui loro device Android lettori biometrici perfetti. I modelli da seguire dovranno essere – ovviamente – i Nexus 6P e 5X.
7.3.10. Fingerprint Sensor
Device implementations with a secure lock screen SHOULD include a fingerprint sensor. If a device implementation includes a fingerprint sensor and has a corresponding API for third-party developers, it:
- MUST declare support for the android.hardware.fingerprint feature.
- MUST fully implement the corresponding API as described in the Android SDK documentation [Resources, 95].
- MUST have a false acceptance rate not higher than 0.002%.
- Is STRONGLY RECOMMENDED to have a false rejection rate not higher than 10%, and a latency from when the fingerprint sensor is touched until the screen is unlocked below 1 second, for 1 enrolled finger.
- MUST rate limit attempts for at least 30 seconds after 5 false trials for fingerprint verification.
- MUST have a hardware-backed keystore implementation, and perform the fingerprint matching in a Trusted Execution Environment (TEE) or on a chip with a secure channel to the TEE.
- MUST have all identifiable fingerprint data encrypted and cryptographically authenticated such that they cannot be acquired, read or altered outside of the Trusted Execution Environment (TEE) as documented in the implementation guidelines on the Android Open Source Project site [Resources, 96].
- MUST prevent adding a fingerprint without first establishing a chain of trust by having the user confirm existing or add a new device credential (PIN/pattern/password) using the TEE as implemented in the Android Open Source project.
- MUST NOT enable 3rd-party applications to distinguish between individual fingerprints.
- MUST honor the DevicePolicyManager.KEYGUARD_DISABLE_FINGERPRINT flag.
- MUST, when upgraded from a version earlier than Android 6.0, have the fingerprint data securely migrated to meet the above requirements or removed.
- SHOULD use the Android Fingerprint icon provided in the Android Open Source Project.
Google raccomanda quindi l’uso del sensore su tutti gli smartphone. Tanti obblighi e alcuni suggerimenti, uno tra tutti quello relativo alle performance di precisione e velocità, come su Nexus 6P e 5X.