CredentialAuthExtensionsKt

Added in 1.4.0-alpha02

public final class CredentialAuthExtensionsKt


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

@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

@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.

authenticateWithCredentials

@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.

startCredentialAuthentication

@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.

startCredentialAuthentication

@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.