A sample that demonstrates to use registered fingerprints to authenticate the user in your app
This sample demonstrates how you can use registered fingerprints in your app to authenticate the user before proceeding some actions such as purchasing an item.
First you need to create an asymmetric key pair in the Android Key Store using KeyPairGenerator in the way that its private key can only be used after the user has authenticated with fingerprint and transmit the public key to your backend with the user verified password (In a real world, the app should show proper UIs).
By setting KeyGenParameterSpec.Builder.setUserAuthenticationRequired to true, you can permit the use of the key only after the user authenticate it including when authenticated with the user's fingerprint.
Then start listening to a fingerprint on the fingerprint sensor by calling FingerprintManager.authenticate with a Signature initialized with the asymmetric key pair created. Or alternatively you can fall back to server-side verified password as an authenticator.
Once the fingerprint (or password) is verified, the FingerprintManager.AuthenticationCallback#onAuthenticationSucceeded() callback is called.
Then you can verify the purchase transaction on server side with the public key passed from the client, by verifying the piece of data signed by the Signature.
This sample uses the Gradle build system. To build this project, use the “gradlew build” command or use “Import Project” in Android Studio.
If you've found an error in this sample, please file an issue: https://github.com/googlesamples/android-AsymmetricFingerprintDialog
Patches are encouraged, and may be submitted by forking this project and submitting a pull request through GitHub. Please see CONTRIBUTING.md for more details.
Copyright 2016 The Android Open Source Project, Inc.
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