Added in API level 23

KeyInfo

---

Kotlin |Java

open class KeyInfo : KeySpec

kotlin.Any
↳	android.security.keystore.KeyInfo

Information about a key from the Android Keystore system. This class describes whether the key material is available in plaintext outside of secure hardware, whether user authentication is required for using the key and whether this requirement is enforced by secure hardware, the key's origin, what uses the key is authorized for (e.g., only in GCM mode, or signing only), whether the key should be encrypted at rest, the key's and validity start and end dates.

Instances of this class are immutable.

Example: Symmetric Key

The following example illustrates how to obtain a KeyInfo describing the provided Android Keystore SecretKey.

<code>SecretKey key = ...; // Android Keystore key
 
  SecretKeyFactory factory = SecretKeyFactory.getInstance(key.getAlgorithm(), "AndroidKeyStore");
  KeyInfo keyInfo;
  try {
      keyInfo = (KeyInfo) factory.getKeySpec(key, KeyInfo.class);
  } catch (InvalidKeySpecException e) {
      // Not an Android KeyStore key.
  }</code>

Example: Private Key

The following example illustrates how to obtain a KeyInfo describing the provided Android KeyStore PrivateKey.

<code>PrivateKey key = ...; // Android KeyStore key
 
  KeyFactory factory = KeyFactory.getInstance(key.getAlgorithm(), "AndroidKeyStore");
  KeyInfo keyInfo;
  try {
      keyInfo = factory.getKeySpec(key, KeyInfo.class);
  } catch (InvalidKeySpecException e) {
      // Not an Android KeyStore key.
  }</code>

Summary

Public methods
open Array<String!>	getBlockModes() Gets the set of block modes (e.g.,
open Array<String!>	getDigests() Gets the set of digest algorithms (e.g.,
open Array<String!>	getEncryptionPaddings() Gets the set of padding schemes (e.g.,
open Int	getKeySize() Gets the size of the key in bits.
open Date?	getKeyValidityForConsumptionEnd() Gets the time instant after which the key is no long valid for decryption and verification.
open Date?	getKeyValidityForOriginationEnd() Gets the time instant after which the key is no long valid for encryption and signing.
open Date?	getKeyValidityStart() Gets the time instant before which the key is not yet valid.
open String!	getKeystoreAlias() Gets the entry alias under which the key is stored in the AndroidKeyStore.
open Int	getOrigin() Gets the origin of the key.
open Int	getPurposes() Gets the set of purposes (e.g., encrypt, decrypt, sign) for which the key can be used.
open Int	getRemainingUsageCount() Returns the remaining number of times the key is allowed to be used or KeyProperties.UNRESTRICTED_USAGE_COUNT if there's no restriction on the number of times the key can be used.
open Int	getSecurityLevel() Returns the security level that the key is protected by.
open Array<String!>	getSignaturePaddings() Gets the set of padding schemes (e.g.,
open Int	getUserAuthenticationType() Gets the acceptable user authentication types for which this key can be authorized to be used.
open Int	getUserAuthenticationValidityDurationSeconds() Gets the duration of time (seconds) for which this key is authorized to be used after the user is successfully authenticated.
open Boolean	isInsideSecureHardware() Returns true if the key resides inside secure hardware (e.g., Trusted Execution Environment (TEE) or Secure Element (SE)).
open Boolean	isInvalidatedByBiometricEnrollment() Returns true if the key will be invalidated by enrollment of a new fingerprint or removal of all fingerprints.
open Boolean	isTrustedUserPresenceRequired() Returns true if the key can only be only be used if a test for user presence has succeeded since Signature.
open Boolean	isUnlockedDeviceRequired() Returns true if the key is authorized to be used only while the device is unlocked.
open Boolean	isUserAuthenticationRequired() Returns true if the key is authorized to be used only if the user has been authenticated.
open Boolean	isUserAuthenticationRequirementEnforcedBySecureHardware() Returns true if the requirement that this key can only be used if the user has been authenticated is enforced by secure hardware (e.g., Trusted Execution Environment (TEE) or Secure Element (SE)).
open Boolean	isUserAuthenticationValidWhileOnBody() Returns true if this key will become unusable when the device is removed from the user's body.
open Boolean	isUserConfirmationRequired() Returns true if the key is authorized to be used only for messages confirmed by the user.

Public methods

getBlockModes

Added in API level 23

open fun getBlockModes(): Array<String!>

Gets the set of block modes (e.g., GCM, CBC) with which the key can be used when encrypting/decrypting. Attempts to use the key with any other block modes will be rejected.

See KeyProperties.BLOCK_MODE constants.

Return
Array<String!>	This value cannot be null. Value is android.security.keystore.KeyProperties#BLOCK_MODE_ECB, android.security.keystore.KeyProperties#BLOCK_MODE_CBC, android.security.keystore.KeyProperties#BLOCK_MODE_CTR, or android.security.keystore.KeyProperties#BLOCK_MODE_GCM

getDigests

Added in API level 23

open fun getDigests(): Array<String!>

Gets the set of digest algorithms (e.g., SHA-256, SHA-384) with which the key can be used.

See KeyProperties.DIGEST constants.

Return

Array<String!>

This value cannot be null. Value is android.security.keystore.KeyProperties#DIGEST_NONE, android.security.keystore.KeyProperties#DIGEST_MD5, android.security.keystore.KeyProperties#DIGEST_SHA1, android.security.keystore.KeyProperties#DIGEST_SHA224, android.security.keystore.KeyProperties#DIGEST_SHA256, android.security.keystore.KeyProperties#DIGEST_SHA384, or android.security.keystore.KeyProperties#DIGEST_SHA512

getEncryptionPaddings

Added in API level 23

open fun getEncryptionPaddings(): Array<String!>

Gets the set of padding schemes (e.g., PKCS7Padding, PKCS1Padding, NoPadding) with which the key can be used when encrypting/decrypting. Attempts to use the key with any other padding scheme will be rejected.

See KeyProperties.ENCRYPTION_PADDING constants.

Return
Array<String!>	This value cannot be null. Value is android.security.keystore.KeyProperties#ENCRYPTION_PADDING_NONE, android.security.keystore.KeyProperties#ENCRYPTION_PADDING_PKCS7, android.security.keystore.KeyProperties#ENCRYPTION_PADDING_RSA_PKCS1, or android.security.keystore.KeyProperties#ENCRYPTION_PADDING_RSA_OAEP

getKeySize

Added in API level 23

open fun getKeySize(): Int

Gets the size of the key in bits.

getKeyValidityForConsumptionEnd

Added in API level 23

open fun getKeyValidityForConsumptionEnd(): Date?

Gets the time instant after which the key is no long valid for decryption and verification.

Return
Date?	instant or null if not restricted.

getKeyValidityForOriginationEnd

Added in API level 23

open fun getKeyValidityForOriginationEnd(): Date?

Gets the time instant after which the key is no long valid for encryption and signing.

Return
Date?	instant or null if not restricted.

getKeyValidityStart

Added in API level 23

open fun getKeyValidityStart(): Date?

Gets the time instant before which the key is not yet valid.

Return
Date?	instant or null if not restricted.

getKeystoreAlias

Added in API level 23

open fun getKeystoreAlias(): String!

Gets the entry alias under which the key is stored in the AndroidKeyStore.

getOrigin

Added in API level 23

open fun getOrigin(): Int

Gets the origin of the key. See KeyProperties.ORIGIN constants.

Return
Int	Value is android.security.keystore.KeyProperties#ORIGIN_GENERATED, android.security.keystore.KeyProperties#ORIGIN_IMPORTED, or android.security.keystore.KeyProperties#ORIGIN_UNKNOWN

getPurposes

Added in API level 23

open fun getPurposes(): Int

Gets the set of purposes (e.g., encrypt, decrypt, sign) for which the key can be used. Attempts to use the key for any other purpose will be rejected.

See KeyProperties.PURPOSE flags.

Return

Int

Value is either 0 or a combination of android.security.keystore.KeyProperties#PURPOSE_ENCRYPT, android.security.keystore.KeyProperties#PURPOSE_DECRYPT, android.security.keystore.KeyProperties#PURPOSE_SIGN, android.security.keystore.KeyProperties#PURPOSE_VERIFY, android.security.keystore.KeyProperties#PURPOSE_WRAP_KEY, android.security.keystore.KeyProperties#PURPOSE_AGREE_KEY, and android.security.keystore.KeyProperties#PURPOSE_ATTEST_KEY

getRemainingUsageCount

Added in API level 31

open fun getRemainingUsageCount(): Int

Returns the remaining number of times the key is allowed to be used or KeyProperties.UNRESTRICTED_USAGE_COUNT if there's no restriction on the number of times the key can be used. Note that this gives a best effort count and need not be accurate (as there might be usages happening in parallel and the count maintained here need not be in sync with the usage).

getSecurityLevel

Added in API level 31

open fun getSecurityLevel(): Int

Returns the security level that the key is protected by. KeyProperties.SecurityLevelEnum.TRUSTED_ENVIRONMENT and KeyProperties.SecurityLevelEnum.STRONGBOX indicate that the key material resides in secure hardware. Key material of such keys is available in plaintext only inside the secure hardware and is not exposed outside of it.

See KeyProperties.SecurityLevelEnum constants.

Return
Int	Value is android.security.keystore.KeyProperties#SECURITY_LEVEL_UNKNOWN, android.security.keystore.KeyProperties#SECURITY_LEVEL_UNKNOWN_SECURE, android.security.keystore.KeyProperties#SECURITY_LEVEL_SOFTWARE, android.security.keystore.KeyProperties#SECURITY_LEVEL_TRUSTED_ENVIRONMENT, or android.security.keystore.KeyProperties#SECURITY_LEVEL_STRONGBOX

getSignaturePaddings

Added in API level 23

open fun getSignaturePaddings(): Array<String!>

Gets the set of padding schemes (e.g., PSS, PKCS#1) with which the key can be used when signing/verifying. Attempts to use the key with any other padding scheme will be rejected.

See KeyProperties.SIGNATURE_PADDING constants.

Return
Array<String!>	This value cannot be null. Value is android.security.keystore.KeyProperties#SIGNATURE_PADDING_RSA_PKCS1, or android.security.keystore.KeyProperties#SIGNATURE_PADDING_RSA_PSS

getUserAuthenticationType

Added in API level 30

open fun getUserAuthenticationType(): Int

Gets the acceptable user authentication types for which this key can be authorized to be used. This has effect only if user authentication is required (see isUserAuthenticationRequired()).

This authorization applies only to secret key and private key operations. Public key operations are not restricted.

Return
Int	integer representing the accepted forms of user authentication for this key Value is either 0 or a combination of android.security.keystore.KeyProperties#AUTH_BIOMETRIC_STRONG, and android.security.keystore.KeyProperties#AUTH_DEVICE_CREDENTIAL

See Also

• #isUserAuthenticationRequired()

getUserAuthenticationValidityDurationSeconds

Added in API level 23

open fun getUserAuthenticationValidityDurationSeconds(): Int

Gets the duration of time (seconds) for which this key is authorized to be used after the user is successfully authenticated. This has effect only if user authentication is required (see isUserAuthenticationRequired()).

This authorization applies only to secret key and private key operations. Public key operations are not restricted.

Return
Int	duration in seconds or -1 if authentication is required for every use of the key.

See Also

• #isUserAuthenticationRequired()

isInsideSecureHardware

Added in API level 23
Deprecated in API level 31

open fun isInsideSecureHardware(): Boolean

Deprecated: This method is superseded by @see getSecurityLevel.

Returns true if the key resides inside secure hardware (e.g., Trusted Execution Environment (TEE) or Secure Element (SE)). Key material of such keys is available in plaintext only inside the secure hardware and is not exposed outside of it.

isInvalidatedByBiometricEnrollment

Added in API level 24

open fun isInvalidatedByBiometricEnrollment(): Boolean

Returns true if the key will be invalidated by enrollment of a new fingerprint or removal of all fingerprints.

isTrustedUserPresenceRequired

Added in API level 28

open fun isTrustedUserPresenceRequired(): Boolean

Returns true if the key can only be only be used if a test for user presence has succeeded since Signature.initSign() has been called.

isUnlockedDeviceRequired

Added in API level Baklava

open fun isUnlockedDeviceRequired(): Boolean

Returns true if the key is authorized to be used only while the device is unlocked.

This authorization applies only to secret key and private key operations. Public key operations are not restricted.

See Also

• android.security.keystore.KeyGenParameterSpec.Builder#setUnlockedDeviceRequired(boolean)
• android.security.keystore.KeyProtection.Builder#setUnlockedDeviceRequired(boolean)

isUserAuthenticationRequired

Added in API level 23

open fun isUserAuthenticationRequired(): Boolean

Returns true if the key is authorized to be used only if the user has been authenticated.

This authorization applies only to secret key and private key operations. Public key operations are not restricted.

See Also

• #getUserAuthenticationValidityDurationSeconds()
• android.security.keystore.KeyGenParameterSpec.Builder#setUserAuthenticationRequired(boolean)
• android.security.keystore.KeyProtection.Builder#setUserAuthenticationRequired(boolean)

isUserAuthenticationRequirementEnforcedBySecureHardware

Added in API level 23

open fun isUserAuthenticationRequirementEnforcedBySecureHardware(): Boolean

Returns true if the requirement that this key can only be used if the user has been authenticated is enforced by secure hardware (e.g., Trusted Execution Environment (TEE) or Secure Element (SE)).

See Also

• #isUserAuthenticationRequired()

isUserAuthenticationValidWhileOnBody

Added in API level 24

open fun isUserAuthenticationValidWhileOnBody(): Boolean

Returns true if this key will become unusable when the device is removed from the user's body. This is possible only for keys with a specified validity duration, and only on devices with an on-body sensor. Always returns false on devices that lack an on-body sensor.

isUserConfirmationRequired

Added in API level 28

open fun isUserConfirmationRequired(): Boolean

Returns true if the key is authorized to be used only for messages confirmed by the user. Confirmation is separate from user authentication (see isUserAuthenticationRequired()). Keys can be created that require confirmation but not user authentication, or user authentication but not confirmation, or both. Confirmation verifies that some user with physical possession of the device has approved a displayed message. User authentication verifies that the correct user is present and has authenticated.

This authorization applies only to secret key and private key operations. Public key operations are not restricted.

See Also

• android.security.keystore.KeyGenParameterSpec.Builder#setUserConfirmationRequired(boolean)
• android.security.keystore.KeyProtection.Builder#setUserConfirmationRequired(boolean)