1 2Android AsymmetricFingerprintDialog Sample 3=================================== 4 5A sample that demonstrates to use registered fingerprints to authenticate the user in your app 6 7Introduction 8------------ 9 10This sample demonstrates how you can use registered fingerprints in your app to authenticate the 11user before proceeding some actions such as purchasing an item. 12 13First you need to create an asymmetric key pair in the Android Key Store using [KeyPairGenerator][1] 14in the way that its private key can only be used after the user has authenticated with fingerprint 15and transmit the public key to your backend with the user verified password (In a real world, the 16app should show proper UIs). 17 18By setting [KeyGenParameterSpec.Builder.setUserAuthenticationRequired][2] to true, you can permit the 19use of the key only after the user authenticate it including when authenticated with the user's 20fingerprint. 21 22Then start listening to a fingerprint on the fingerprint sensor by calling 23[FingerprintManager.authenticate][3] with a [Signature][4] initialized with the asymmetric key pair 24created. Or alternatively you can fall back to server-side verified password as an authenticator. 25 26Once the fingerprint (or password) is verified, the 27[FingerprintManager.AuthenticationCallback#onAuthenticationSucceeded()][5] callback is called. 28 29Then you can verify the purchase transaction on server side with the public key passed from the 30client, by verifying the piece of data signed by the Signature. 31 32[1]: https://developer.android.com/reference/java/security/KeyPairGenerator.html 33[2]: https://developer.android.com/reference/android/security/keystore/KeyGenParameterSpec.Builder.html#setUserAuthenticationRequired%28boolean%29 34[3]: https://developer.android.com/reference/android/hardware/fingerprint/FingerprintManager.html#authenticate%28android.hardware.fingerprint.FingerprintManager.CryptoObject,%20android.os.CancellationSignal,%20int,%20android.hardware.fingerprint.FingerprintManager.AuthenticationCallback,%20android.os.Handler%29 35[4]: https://developer.android.com/reference/java/security/Signature.html 36[5]: https://developer.android.com/reference/android/hardware/fingerprint/FingerprintManager.AuthenticationCallback.html#onAuthenticationSucceeded%28android.hardware.fingerprint.FingerprintManager.AuthenticationResult%29 37 38Pre-requisites 39-------------- 40 41- Android SDK 27 42- Android Build Tools v27.0.2 43- Android Support Repository 44 45Screenshots 46------------- 47 48<img src="screenshots/1-purchase-screen.png" height="400" alt="Screenshot"/> <img src="screenshots/2-fingerprint-dialog.png" height="400" alt="Screenshot"/> <img src="screenshots/3-fingerprint-authenticated.png" height="400" alt="Screenshot"/> <img src="screenshots/4-new-fingerprint-enrolled.png" height="400" alt="Screenshot"/> 49 50Getting Started 51--------------- 52 53This sample uses the Gradle build system. To build this project, use the 54"gradlew build" command or use "Import Project" in Android Studio. 55 56Support 57------- 58 59- Google+ Community: https://plus.google.com/communities/105153134372062985968 60- Stack Overflow: http://stackoverflow.com/questions/tagged/android 61 62If you've found an error in this sample, please file an issue: 63https://github.com/googlesamples/android-AsymmetricFingerprintDialog 64 65Patches are encouraged, and may be submitted by forking this project and 66submitting a pull request through GitHub. Please see CONTRIBUTING.md for more details. 67 68License 69------- 70 71Copyright 2017 The Android Open Source Project, Inc. 72 73Licensed to the Apache Software Foundation (ASF) under one or more contributor 74license agreements. See the NOTICE file distributed with this work for 75additional information regarding copyright ownership. The ASF licenses this 76file to you under the Apache License, Version 2.0 (the "License"); you may not 77use this file except in compliance with the License. You may obtain a copy of 78the License at 79 80http://www.apache.org/licenses/LICENSE-2.0 81 82Unless required by applicable law or agreed to in writing, software 83distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 84WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 85License for the specific language governing permissions and limitations under 86the License. 87
