mirror of https://github.com/Corewala/Buran
104 lines
4.2 KiB
Kotlin
104 lines
4.2 KiB
Kotlin
package corewala.buran.io.keymanager
|
|
|
|
import android.app.Activity
|
|
import android.content.Context
|
|
import android.os.Build
|
|
import android.security.keystore.KeyGenParameterSpec
|
|
import android.security.keystore.KeyProperties
|
|
import androidx.annotation.RequiresApi
|
|
import androidx.biometric.BiometricPrompt
|
|
import androidx.core.content.ContextCompat
|
|
import androidx.fragment.app.Fragment
|
|
import androidx.fragment.app.FragmentActivity
|
|
import corewala.buran.Buran
|
|
import corewala.buran.R
|
|
import java.nio.charset.Charset
|
|
import java.security.KeyStore
|
|
import javax.crypto.Cipher
|
|
import javax.crypto.KeyGenerator
|
|
import javax.crypto.SecretKey
|
|
import javax.crypto.spec.GCMParameterSpec
|
|
|
|
data class EncryptedData(val ciphertext: ByteArray, val initializationVector: ByteArray)
|
|
|
|
@RequiresApi(Build.VERSION_CODES.P)
|
|
class BuranBiometricManager {
|
|
|
|
private lateinit var biometricPrompt: BiometricPrompt
|
|
private lateinit var promptInfo: BiometricPrompt.PromptInfo
|
|
|
|
fun createBiometricPrompt(context: Context, fragment: Fragment, callback: BiometricPrompt.AuthenticationCallback){
|
|
val executor = ContextCompat.getMainExecutor(context)
|
|
biometricPrompt = BiometricPrompt(fragment, executor, callback)
|
|
promptInfo = BiometricPrompt.PromptInfo.Builder()
|
|
.setConfirmationRequired(false)
|
|
.setTitle(context.getString(R.string.confirm_your_identity))
|
|
.setSubtitle(context.getString(R.string.use_biometric_unlock))
|
|
.setNegativeButtonText(context.getString(R.string.cancel).toUpperCase())
|
|
.build()
|
|
}
|
|
|
|
fun authenticateToEncryptData() {
|
|
val cipher = getCipher()
|
|
val secretKey = getSecretKey(Buran.CLIENT_CERT_PASSWORD_SECRET_KEY_NAME)
|
|
cipher.init(Cipher.ENCRYPT_MODE, secretKey)
|
|
biometricPrompt.authenticate(promptInfo, BiometricPrompt.CryptoObject(cipher))
|
|
}
|
|
|
|
fun authenticateToDecryptData(initializationVector: ByteArray) {
|
|
val cipher = getCipher()
|
|
val secretKey = getSecretKey(Buran.CLIENT_CERT_PASSWORD_SECRET_KEY_NAME)
|
|
cipher.init(Cipher.DECRYPT_MODE, secretKey, GCMParameterSpec(128, initializationVector))
|
|
biometricPrompt.authenticate(promptInfo, BiometricPrompt.CryptoObject(cipher))
|
|
}
|
|
|
|
// Allows ByteArrays to be stored in prefs as strings. Possibly the most horrifying function I've ever written.
|
|
fun decodeByteArray(encodedByteArray: String): ByteArray{
|
|
val byteList = encodedByteArray.substring(1, encodedByteArray.length - 1).split(", ")
|
|
var decodedByteArray = byteArrayOf()
|
|
for(byte in byteList){
|
|
decodedByteArray += byte.toInt().toByte()
|
|
}
|
|
println(decodedByteArray.contentToString())
|
|
return decodedByteArray
|
|
}
|
|
|
|
fun encryptData(plaintext: String, cipher: Cipher): EncryptedData {
|
|
val ciphertext = cipher.doFinal(plaintext.toByteArray(Charset.forName("UTF-8")))
|
|
return EncryptedData(ciphertext,cipher.iv)
|
|
}
|
|
|
|
fun decryptData(ciphertext: ByteArray, cipher: Cipher): String {
|
|
val plaintext = cipher.doFinal(ciphertext)
|
|
return String(plaintext, Charset.forName("UTF-8"))
|
|
}
|
|
|
|
private fun getCipher(): Cipher {
|
|
val transformation = "${KeyProperties.KEY_ALGORITHM_AES}/${KeyProperties.BLOCK_MODE_GCM}/${KeyProperties.ENCRYPTION_PADDING_NONE}"
|
|
return Cipher.getInstance(transformation)
|
|
}
|
|
|
|
private fun getSecretKey(keyName: String): SecretKey {
|
|
val androidKeystore = "AndroidKeyStore"
|
|
val keyStore = KeyStore.getInstance(androidKeystore)
|
|
keyStore.load(null)
|
|
keyStore.getKey(keyName, null)?.let { return it as SecretKey }
|
|
|
|
val keyGenParams = KeyGenParameterSpec.Builder(
|
|
keyName,
|
|
KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT
|
|
).apply {
|
|
setBlockModes(KeyProperties.BLOCK_MODE_GCM)
|
|
setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
|
|
setKeySize(256)
|
|
setUserAuthenticationRequired(true)
|
|
}.build()
|
|
|
|
val keyGenerator = KeyGenerator.getInstance(
|
|
KeyProperties.KEY_ALGORITHM_AES,
|
|
androidKeystore
|
|
)
|
|
keyGenerator.init(keyGenParams)
|
|
return keyGenerator.generateKey()
|
|
}
|
|
} |