MasterKey

Kotlin |Java

class MasterKey

kotlin.Any
↳	androidx.security.crypto.MasterKey

Wrapper for a master key used in the library. On Android M (API 23) and above, this is class references a key that's stored in the Android Keystore. On Android L (API 21, 22), there isn't a master key.

Summary

Nested classes
	Builder Builder for generating a MasterKey.
	KeyScheme Algorithm/Cipher choices used for the master key.

Constants
static Int	DEFAULT_AES_GCM_MASTER_KEY_SIZE The default and recommended size for the master key.
static String	DEFAULT_MASTER_KEY_ALIAS The default master key alias.

Public methods
static Int	getDefaultAuthenticationValidityDurationSeconds() The default validity period for authentication in seconds.
Int	getUserAuthenticationValidityDurationSeconds() Gets the duration in seconds that the key is unlocked for following user authentication.
Boolean	isKeyStoreBacked() Checks if this key is backed by the Android Keystore.
Boolean	isStrongBoxBacked() Gets whether the key is backed by strong box.
Boolean	isUserAuthenticationRequired() Gets whether user authentication is required to use this key.
String	toString()

Constants

DEFAULT_AES_GCM_MASTER_KEY_SIZE

static val DEFAULT_AES_GCM_MASTER_KEY_SIZE: Int

The default and recommended size for the master key.

Value: 256

DEFAULT_MASTER_KEY_ALIAS

static val DEFAULT_MASTER_KEY_ALIAS: String

The default master key alias.

Value: "_androidx_security_master_key_"

Public methods

getDefaultAuthenticationValidityDurationSeconds

static fun getDefaultAuthenticationValidityDurationSeconds(): Int

The default validity period for authentication in seconds.

getUserAuthenticationValidityDurationSeconds

fun getUserAuthenticationValidityDurationSeconds(): Int

Gets the duration in seconds that the key is unlocked for following user authentication. The value returned for this method is only meaningful on Android M+ (API 23) when isUserAuthenticationRequired() returns true.

Return
Int	The duration the key is unlocked for in seconds.

isKeyStoreBacked

fun isKeyStoreBacked(): Boolean

Checks if this key is backed by the Android Keystore.

Return
Boolean	true if the key is in Android Keystore, false otherwise. This method always returns false when called on Android Lollipop (API 21 and 22).

isStrongBoxBacked

fun isStrongBoxBacked(): Boolean

Gets whether the key is backed by strong box.

isUserAuthenticationRequired

fun isUserAuthenticationRequired(): Boolean

Gets whether user authentication is required to use this key. This method always returns false on Android L (API 21 + 22).

toString

@NonNull fun toString(): String