CredentialAuthExtensionsKt

Added in 1.4.0-alpha02

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Kotlin |Java

public final class CredentialAuthExtensionsKt

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Summary

Public methods
static final @NonNull BiometricPrompt.AuthenticationResult	@RequiresApi(value = 30) authenticate(     @NonNull CredentialAuthPrompt receiver,     @NonNull AuthPromptHost host,     BiometricPrompt.CryptoObject crypto ) Shows an authentication prompt to the user.
static final @NonNull BiometricPrompt.AuthenticationResult	@RequiresApi(value = 30) authenticateWithCredentials(     @NonNull Fragment receiver,     BiometricPrompt.CryptoObject crypto,     @NonNull CharSequence title,     CharSequence description ) Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.
static final @NonNull BiometricPrompt.AuthenticationResult	@RequiresApi(value = 30) authenticateWithCredentials(     @NonNull FragmentActivity receiver,     BiometricPrompt.CryptoObject crypto,     @NonNull CharSequence title,     CharSequence description ) Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.
static final @NonNull AuthPrompt	@RequiresApi(value = 30) startCredentialAuthentication(     @NonNull Fragment receiver,     BiometricPrompt.CryptoObject crypto,     @NonNull CharSequence title,     CharSequence description,     Executor executor,     @NonNull AuthPromptCallback callback ) Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.
static final @NonNull AuthPrompt	@RequiresApi(value = 30) startCredentialAuthentication(     @NonNull FragmentActivity receiver,     BiometricPrompt.CryptoObject crypto,     @NonNull CharSequence title,     CharSequence description,     Executor executor,     @NonNull AuthPromptCallback callback ) Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.

Public methods

authenticate

Artifact: androidx.biometric:biometric-ktx

View Source

@RequiresApi(value = 30)
public static final @NonNull BiometricPrompt.AuthenticationResult authenticate(
    @NonNull CredentialAuthPrompt receiver,
    @NonNull AuthPromptHost host,
    BiometricPrompt.CryptoObject crypto
)

Shows an authentication prompt to the user.

import androidx.biometric.BiometricPrompt
import androidx.biometric.auth.AuthPromptErrorException
import androidx.biometric.auth.AuthPromptFailureException
import androidx.biometric.auth.AuthPromptHost
import androidx.biometric.auth.CredentialAuthPrompt
import androidx.biometric.auth.authenticate

// To use credential authentication, we need to create a CryptoObject.
// First create a spec for the key to be generated.
val keyPurpose = KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT
val keySpec =
    KeyGenParameterSpec.Builder(KEY_NAME, keyPurpose)
        .apply {
            setBlockModes(KeyProperties.BLOCK_MODE_CBC)
            setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
            setUserAuthenticationRequired(true)

            // Require authentication for each use of the key.
            val timeout = 0
            // Set the key type according to the allowed auth type.
            val keyType = KeyProperties.AUTH_DEVICE_CREDENTIAL
            setUserAuthenticationParameters(timeout, keyType)
        }
        .build()

// Generate and store the key in the Android keystore.
KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, KEYSTORE_INSTANCE).run {
    init(keySpec)
    generateKey()
}

// Prepare the crypto object to use for authentication.
val cipher =
    Cipher.getInstance(
            "${KeyProperties.KEY_ALGORITHM_AES}/${KeyProperties.BLOCK_MODE_CBC}/" +
                KeyProperties.ENCRYPTION_PADDING_PKCS7
        )
        .apply {
            val keyStore = KeyStore.getInstance(KEYSTORE_INSTANCE).apply { load(null) }
            init(Cipher.ENCRYPT_MODE, keyStore.getKey(KEY_NAME, null) as SecretKey)
        }

val cryptoObject = BiometricPrompt.CryptoObject(cipher)
val payload = "A message to encrypt".toByteArray(Charset.defaultCharset())

// Construct AuthPrompt with localized Strings to be displayed to UI.
val authPrompt =
    CredentialAuthPrompt.Builder(title).apply { setDescription(description) }.build()

try {
    val authResult = authPrompt.authenticate(AuthPromptHost(this), cryptoObject)

    // Encrypt a payload using the result of crypto-based auth.
    val encryptedPayload = authResult.cryptoObject?.cipher?.doFinal(payload)

    // Use the encrypted payload somewhere interesting.
    sendEncryptedPayload(encryptedPayload)
} catch (e: AuthPromptErrorException) {
    // Handle irrecoverable error during authentication.
    // Possible values for AuthPromptErrorException.errorCode are listed in the @IntDef,
    // androidx.biometric.BiometricPrompt.AuthenticationError.
} catch (e: AuthPromptFailureException) {
    // Handle auth failure due biometric credentials being rejected.
}

Parameters
@NonNull AuthPromptHost host	A wrapper for the component that will host the prompt.
BiometricPrompt.CryptoObject crypto	A cryptographic object to be associated with this authentication.

Returns
@NonNull BiometricPrompt.AuthenticationResult	AuthenticationResult for a successful authentication.

Throws
androidx.biometric.auth.AuthPromptErrorException	when an unrecoverable error has been encountered and authentication has stopped.
androidx.biometric.auth.AuthPromptFailureException	when an authentication attempt by the user has been rejected.

See also
authenticate	( AuthPromptHost host, BiometricPrompt.CryptoObject, AuthPromptCallback )

authenticateWithCredentials

Artifact: androidx.biometric:biometric-ktx

View Source

@RequiresApi(value = 30)
public static final @NonNull BiometricPrompt.AuthenticationResult authenticateWithCredentials(
    @NonNull Fragment receiver,
    BiometricPrompt.CryptoObject crypto,
    @NonNull CharSequence title,
    CharSequence description
)

Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.

Parameters
BiometricPrompt.CryptoObject crypto	A cryptographic object to be associated with this authentication.
@NonNull CharSequence title	The title to be displayed on the prompt.
CharSequence description	An optional description to be displayed on the prompt.

Returns
@NonNull BiometricPrompt.AuthenticationResult	AuthenticationResult for a successful authentication.

Throws
androidx.biometric.auth.AuthPromptErrorException	when an unrecoverable error has been encountered and authentication has stopped.
androidx.biometric.auth.AuthPromptFailureException	when an authentication attempt by the user has been rejected.

See also
CredentialAuthPrompt

authenticateWithCredentials

Artifact: androidx.biometric:biometric-ktx

View Source

@RequiresApi(value = 30)
public static final @NonNull BiometricPrompt.AuthenticationResult authenticateWithCredentials(
    @NonNull FragmentActivity receiver,
    BiometricPrompt.CryptoObject crypto,
    @NonNull CharSequence title,
    CharSequence description
)

Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.

Parameters
BiometricPrompt.CryptoObject crypto	A cryptographic object to be associated with this authentication.
@NonNull CharSequence title	The title to be displayed on the prompt.
CharSequence description	An optional description to be displayed on the prompt.

Returns
@NonNull BiometricPrompt.AuthenticationResult	AuthenticationResult for a successful authentication.

Throws
androidx.biometric.auth.AuthPromptErrorException	when an unrecoverable error has been encountered and authentication has stopped.
androidx.biometric.auth.AuthPromptFailureException	when an authentication attempt by the user has been rejected.

See also
CredentialAuthPrompt

startCredentialAuthentication

Artifact: androidx.biometric:biometric-ktx

View Source

Added in 1.4.0-alpha02

@RequiresApi(value = 30)
public static final @NonNull AuthPrompt startCredentialAuthentication(
    @NonNull Fragment receiver,
    BiometricPrompt.CryptoObject crypto,
    @NonNull CharSequence title,
    CharSequence description,
    Executor executor,
    @NonNull AuthPromptCallback callback
)

Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.

Parameters
BiometricPrompt.CryptoObject crypto	A cryptographic object to be associated with this authentication.
@NonNull CharSequence title	The title to be displayed on the prompt.
CharSequence description	An optional description to be displayed on the prompt.
Executor executor	An executor for callback methods. If null, these will run on the main thread.
@NonNull AuthPromptCallback callback	The object that will receive and process authentication events.

Returns
@NonNull AuthPrompt	An AuthPrompt handle to the shown prompt.

See also
CredentialAuthPrompt

startCredentialAuthentication

Artifact: androidx.biometric:biometric-ktx

View Source

Added in 1.4.0-alpha02

@RequiresApi(value = 30)
public static final @NonNull AuthPrompt startCredentialAuthentication(
    @NonNull FragmentActivity receiver,
    BiometricPrompt.CryptoObject crypto,
    @NonNull CharSequence title,
    CharSequence description,
    Executor executor,
    @NonNull AuthPromptCallback callback
)

Prompts the user to authenticate with the screen lock credential (i.e. PIN, pattern, or password) for the device.

Parameters
BiometricPrompt.CryptoObject crypto	A cryptographic object to be associated with this authentication.
@NonNull CharSequence title	The title to be displayed on the prompt.
CharSequence description	An optional description to be displayed on the prompt.
Executor executor	An executor for callback methods. If null, these will run on the main thread.
@NonNull AuthPromptCallback callback	The object that will receive and process authentication events.

Returns
@NonNull AuthPrompt	An AuthPrompt handle to the shown prompt.

See also
CredentialAuthPrompt