aW9myBaY

1package com.example.fingerprint
2import android.Manifest
3import android.content.Context
4import android.content.Intent
5import android.content.pm.PackageManager
6import android.hardware.fingerprint.FingerprintManager
7import android.os.CancellationSignal
8import android.widget.Toast
9import androidx.core.app.ActivityCompat
10
11class FingerprintHandler (private val appContext: Context) : FingerprintManager.AuthenticationCallback(){
12    private var cancellationSignal : CancellationSignal? = null
13
14    fun startAuth(manager : FingerprintManager, cryptoObject: FingerprintManager.CryptoObject) {
15        cancellationSignal = CancellationSignal()
16
17        if (ActivityCompat.checkSelfPermission(appContext, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {
18            return
19        }
20        manager.authenticate(cryptoObject, cancellationSignal, 0, this,null)
21    }
22
23    override fun onAuthenticationError(signal: Int, errString: CharSequence) {
24        Toast.makeText(appContext, "Authentication error\n" + errString, Toast.LENGTH_LONG).show()
25    }
26
27    override fun onAuthenticationHelp(signal : Int, helpString: CharSequence) {
28        Toast.makeText(appContext, "Authentication help\n"+ helpString, Toast.LENGTH_LONG).show()
29    }
30
31    override fun onAuthenticationFailed() {
32        Toast.makeText(appContext, "Authentication failed", Toast.LENGTH_LONG).show()
33    }
34
35    override fun onAuthenticationSucceeded(result: FingerprintManager.AuthenticationResult) {
36        Toast.makeText(appContext, "Authentication succeeded.", Toast.LENGTH_LONG).show()
37        val intent = Intent(appContext,Note::class.java)
38        appContext.startActivity(intent)
39
40    }
41}
42// main actrivity
43package com.example.fingerprint
44
45import android.Manifest
46import android.app.KeyguardManager
47import android.content.Context
48import android.content.pm.PackageManager
49import android.hardware.fingerprint.FingerprintManager
50import androidx.appcompat.app.AppCompatActivity
51import android.os.Bundle
52import android.security.keystore.KeyGenParameterSpec
53import android.security.keystore.KeyPermanentlyInvalidatedException
54import android.security.keystore.KeyProperties
55import android.widget.Button
56import android.widget.Toast
57import androidx.core.app.ActivityCompat
58import java.io.IOException
59import java.security.*
60import javax.crypto.Cipher
61import javax.crypto.KeyGenerator
62import javax.crypto.NoSuchPaddingException
63import javax.crypto.SecretKey
64import javax.security.cert.CertificateException
65
66class MainActivity : AppCompatActivity() {
67
68    private var fingerprintManager: FingerprintManager? = null
69    private var keyguardManager: KeyguardManager? = null
70    private var keyStore: KeyStore? = null
71    private var keyGenerator: KeyGenerator? = null
72    private val KEY_NAME = "key_note"
73    private var cipher: Cipher? = null
74    private var cryptoObject: FingerprintManager.CryptoObject? = null
75
76    private var disableBack : Boolean = false
77
78    override fun onBackPressed() {
79        // super.onBackPressed(); commented this line in order to disable back press
80        //Write your code here
81        if (!disableBack) {
82            super.onBackPressed()
83        }
84        else {
85            Toast.makeText(applicationContext, "Back press disabled!", Toast.LENGTH_SHORT).show()
86        }
87    }
88
89    override fun onCreate(savedInstanceState: Bundle?) {
90        super.onCreate(savedInstanceState)
91        setContentView(R.layout.activity_main)
92
93        val button = findViewById<Button>(R.id.button)
94        disableBack = intent.getBooleanExtra("back", false)
95        button.setOnClickListener {
96            Toast.makeText(this,"It works", Toast.LENGTH_LONG).show()
97        }
98
99        if (getManagers()) {
100            generateKey()
101
102            if (cipherInit()) {
103                cipher?.let {
104                    cryptoObject = FingerprintManager.CryptoObject(it)
105                }
106
107                val helper = FingerprintHandler(this)
108
109                if (fingerprintManager != null && cryptoObject != null) {
110                    helper.startAuth(fingerprintManager!!, cryptoObject!!)
111                }
112            }
113        }
114    }
115
116    private fun getManagers() : Boolean {
117        keyguardManager = getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
118        fingerprintManager = getSystemService(Context.FINGERPRINT_SERVICE) as FingerprintManager
119
120        if (keyguardManager?.isKeyguardSecure == false) {
121
122            Toast.makeText(this,
123                "Lock screen security not enabled in Settings",
124                Toast.LENGTH_LONG).show()
125            return false
126        }
127
128        if (ActivityCompat.checkSelfPermission(this,
129                Manifest.permission.USE_FINGERPRINT) !=
130            PackageManager.PERMISSION_GRANTED) {
131            Toast.makeText(this,
132                "Fingerprint authentication permission not enabled",
133                Toast.LENGTH_LONG).show()
134
135            return false
136        }
137
138        if (fingerprintManager?.hasEnrolledFingerprints() == false) {
139            Toast.makeText(this,
140                "Register at least one fingerprint in Settings",
141                Toast.LENGTH_LONG).show()
142            return false
143        }
144        return true
145    }
146
147    private fun generateKey() {
148        try {
149            keyStore = KeyStore.getInstance("AndroidKeyStore")
150        } catch (e: Exception) {
151            e.printStackTrace()
152        }
153        try {
154            keyGenerator = KeyGenerator.getInstance(
155                KeyProperties.KEY_ALGORITHM_AES,
156                "AndroidKeyStore")
157        } catch (e: NoSuchAlgorithmException) {
158            throw RuntimeException(
159                "Failed to get KeyGenerator instance", e)
160        } catch (e: NoSuchProviderException) {
161            throw RuntimeException("Failed to get KeyGenerator instance", e)
162        }
163        try {
164            keyStore?.load(null)
165            keyGenerator?.init(
166                KeyGenParameterSpec.Builder(KEY_NAME,
167                KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT)
168                .setBlockModes(KeyProperties.BLOCK_MODE_CBC)
169                .setUserAuthenticationRequired(true)
170                .setEncryptionPaddings(
171                    KeyProperties.ENCRYPTION_PADDING_PKCS7)
172                .build())
173            keyGenerator?.generateKey()
174        } catch (e: NoSuchAlgorithmException) {
175            throw RuntimeException(e)
176        } catch (e: InvalidAlgorithmParameterException) {
177            throw RuntimeException(e)
178        } catch (e: CertificateException) {
179            throw RuntimeException(e)
180        } catch (e: IOException) {
181            throw RuntimeException(e)
182        }
183    }
184
185    private fun cipherInit(): Boolean {
186        try {
187            cipher = Cipher.getInstance(
188                KeyProperties.KEY_ALGORITHM_AES + "/"
189                        + KeyProperties.BLOCK_MODE_CBC + "/"
190                        + KeyProperties.ENCRYPTION_PADDING_PKCS7)
191        } catch (e: NoSuchAlgorithmException) {
192            throw RuntimeException("Failed to get Cipher", e)
193        } catch (e: NoSuchPaddingException) {
194            throw RuntimeException("Failed to get Cipher", e)
195        }
196
197        try {
198            keyStore?.load(null)
199            val key = keyStore?.getKey(KEY_NAME, null) as SecretKey
200            cipher?.init(Cipher.ENCRYPT_MODE, key)
201            return true
202        } catch (e: KeyPermanentlyInvalidatedException) {
203            return false
204        } catch (e: KeyStoreException) {
205            throw RuntimeException("Failed to init Cipher", e)
206        } catch (e: CertificateException) {
207            throw RuntimeException("Failed to init Cipher", e)
208        } catch (e: UnrecoverableKeyException) {
209            throw RuntimeException("Failed to init Cipher", e)
210        } catch (e: IOException) {
211            throw RuntimeException("Failed to init Cipher", e)
212        } catch (e: NoSuchAlgorithmException) {
213            throw RuntimeException("Failed to init Cipher", e)
214        } catch (e: InvalidKeyException) {
215            throw RuntimeException("Failed to init Cipher", e)
216        }
217    }
218}