IdentityCredential

createEphemeralKeyPair

abstract fun createEphemeralKeyPair(): KeyPair

Deprecated: Use PresentationSession instead.

Create an ephemeral key pair to use to establish a secure channel with a reader.

Applications should use this key-pair for the communications channel with the reader using a protocol / cipher-suite appropriate for the application. One example of such a protocol is the one used for Mobile Driving Licenses, see ISO 18013-5 section 9.2.1 "Session encryption".

decryptMessageFromReader

abstract fun decryptMessageFromReader(messageCiphertext: ByteArray): ByteArray

Deprecated: Applications should use PresentationSession and implement encryption/decryption themselves.

Decrypt a message received from the reader.

Do not use. In this version of the API, this method produces an incorrect result. Instead, applications should implement message encryption/decryption themselves as detailed in the createEphemeralKeyPair() method. In a future API-level, this method will be deprecated.

delete

open fun delete(challenge: ByteArray): ByteArray

Deletes a credential.

This method returns a COSE_Sign1 data structure signed by the CredentialKey with payload set to ProofOfDeletion as defined below.

ProofOfDeletion = [
           "ProofOfDeletion",            ; tstr
           tstr,                         ; DocType
           bstr,                         ; Challenge
           bool                          ; true if this is a test credential, should
                                         ; always be false.
       ]
  

This is only implemented in feature version 202101 or later. If not implemented, the call fails with UnsupportedOperationException. See android.content.pm.PackageManager#FEATURE_IDENTITY_CREDENTIAL_HARDWARE for known feature versions.

encryptMessageToReader

abstract fun encryptMessageToReader(messagePlaintext: ByteArray): ByteArray

Deprecated: Applications should use PresentationSession and implement encryption/decryption themselves.

Encrypt a message for transmission to the reader.

Do not use. In this version of the API, this method produces an incorrect result. Instead, applications should implement message encryption/decryption themselves as detailed in the createEphemeralKeyPair() method. In a future API-level, this method will be deprecated.

getAuthKeysNeedingCertification

abstract fun getAuthKeysNeedingCertification(): MutableCollection<X509Certificate!>

Gets a collection of dynamic authentication keys that need certification.

When there aren't enough certified dynamic authentication keys, either because the key count has been increased or because one or more keys have reached their usage count or it if a key is too close to its expiration date, this method will generate replacement keys and certificates and return them for issuer certification. The issuer certificates and associated static authentication data must then be provided back to the Identity Credential using storeStaticAuthenticationData(java.security.cert.X509Certificate,byte[]). The private part of each authentication key never leaves secure hardware.

Each X.509 certificate is signed by CredentialKey. The certificate chain for CredentialKey can be obtained using the getCredentialKeyCertificateChain() method.

If the implementation is feature version 202101 or later, each X.509 certificate contains an X.509 extension at OID 1.3.6.1.4.1.11129.2.1.26 which contains a DER encoded OCTET STRING with the bytes of the CBOR with the following CDDL:

ProofOfBinding = [
      "ProofOfBinding",
      bstr,              // Contains SHA-256(ProofOfProvisioning)
    ]
  

This CBOR enables an issuer to determine the exact state of the credential it returns issuer-signed data for.

See android.content.pm.PackageManager#FEATURE_IDENTITY_CREDENTIAL_HARDWARE for known feature versions.

getAuthenticationDataUsageCount

abstract fun getAuthenticationDataUsageCount(): IntArray

Deprecated: Use getAuthenticationKeyMetadata() instead.

Get the number of times the dynamic authentication keys have been used.

getAuthenticationKeyMetadata

open fun getAuthenticationKeyMetadata(): MutableList<AuthenticationKeyMetadata!>

Get information about dynamic authentication keys.

The returned list may have null values if certification for the dynamic authentication key is pending.

The list is always keyCount elements long.

getCredentialKeyCertificateChain

abstract fun getCredentialKeyCertificateChain(): MutableCollection<X509Certificate!>

Gets the X.509 certificate chain for the CredentialKey which identifies this credential to the issuing authority. This is the same certificate chain that was returned by WritableIdentityCredential#getCredentialKeyCertificateChain(byte[]) when the credential was first created and its Android Keystore extension will contain the challenge data set at that time. See the documentation for that method for important information about this certificate chain.

getEntries

abstract fun getEntries(
    requestMessage: ByteArray?, 
    entriesToRequest: MutableMap<String!, MutableCollection<String!>!>, 
    sessionTranscript: ByteArray?, 
    readerSignature: ByteArray?
): ResultData

Deprecated: Use PresentationSession instead.

Retrieve data entries and associated data from this IdentityCredential.

If an access control check fails for one of the requested entries or if the entry doesn't exist, the entry is simply not returned. The application can detect this by using the ResultData#getStatus(String, String) method on each of the requested entries.

It is permissible to call this method multiple times using the same instance but if this is done, the sessionTranscript parameter must be identical for each call. If this is not the case, the SessionTranscriptMismatchException exception is thrown. Additionally, if this is done the same auth-key will be used.

The application should not make any assumptions on whether user authentication is needed. Instead, the application should request the data elements values first and then examine the returned ResultData. If ResultData#STATUS_USER_AUTHENTICATION_FAILED is returned the application should get a android.hardware.biometrics.BiometricPrompt.CryptoObject which references this object and use it with a android.hardware.biometrics.BiometricPrompt. Upon successful authentication the application may call getEntries(byte[],java.util.Map,byte[],byte[]) again.

If not null the requestMessage parameter must contain data for the request from the verifier. The content can be defined in the way appropriate for the credential, but there are three requirements that must be met to work with this API:

• The content must be a CBOR-encoded structure.
• The CBOR structure must be a map.
• The map must contain a tstr key "nameSpaces" whose value contains a map, as described in the example below.

If these requirements are not met the InvalidRequestMessageException exception is thrown.

Here's an example of CBOR which conforms to this requirement:

ItemsRequest = {
      ? "docType" : DocType,
      "nameSpaces" : NameSpaces,
      ? "RequestInfo" : {* tstr => any} ; Additional info the reader wants to provide
    }
 
    DocType = tstr
 
    NameSpaces = {
      + NameSpace => DataElements    ; Requested data elements for each NameSpace
    }
 
    NameSpace = tstr
 
    DataElements = {
      + DataElement => IntentToRetain
    }
 
    DataElement = tstr
    IntentToRetain = bool
  

If mdoc session encryption is used (e.g. if createEphemeralKeyPair() has been called) and if the sessionTranscript parameter is not null, the X and Y coordinates of the public part of the key-pair previously generated by createEphemeralKeyPair() must appear somewhere in the bytes of the CBOR. Each of these coordinates must appear encoded with the most significant bits first and use the exact amount of bits indicated by the key size of the ephemeral keys. For example, if the ephemeral key is using the P-256 curve then the 32 bytes for the X coordinate encoded with the most significant bits first must appear somewhere in sessionTranscript and ditto for the 32 bytes for the Y coordinate.

If readerSignature is not null it must be the bytes of a COSE_Sign1 structure as defined in RFC 8152. For the payload nil shall be used and the detached payload is the ReaderAuthenticationBytes CBOR described below.

ReaderAuthentication = [
        "ReaderAuthentication",
        SessionTranscript,
        ItemsRequestBytes
      ]
 
      ItemsRequestBytes = #6.24(bstr .cbor ItemsRequest)
 
      ReaderAuthenticationBytes = #6.24(bstr .cbor ReaderAuthentication)
  

where ItemsRequestBytes are the bytes in the requestMessage parameter.

The public key corresponding to the key used to make the signature, can be found in the x5chain unprotected header element of the COSE_Sign1 structure (as as described in draft-ietf-cose-x509-04). There will be at least one certificate in said element and there may be more (and if so, each certificate must be signed by its successor).

Data elements protected by reader authentication are returned if, and only if, they are mentioned in requestMessage, requestMessage is signed by the top-most certificate in the reader's certificate chain, and the data element is configured with an AccessControlProfile configured with an X.509 certificate which appears in the certificate chain.

Note that only items referenced in entriesToRequest are returned - the requestMessage parameter is used only for enforcing reader authentication.

The reason for having requestMessage and entriesToRequest as separate parameters is that the former represents a request from the remote verifier device (optionally signed) and this allows the application to filter the request to not include data elements which the user has not consented to sharing.

proveOwnership

open fun proveOwnership(challenge: ByteArray): ByteArray

Proves ownership of a credential.

This method returns a COSE_Sign1 data structure signed by the CredentialKey with payload set to ProofOfDeletion as defined below.

The returned CBOR is the following:

ProofOfOwnership = [
           "ProofOfOwnership",           ; tstr
           tstr,                         ; DocType
           bstr,                         ; Challenge
           bool                          ; true if this is a test credential, should
                                         ; always be false.
       ]
  

This is only implemented in feature version 202101 or later. If not implemented, the call fails with UnsupportedOperationException. See android.content.pm.PackageManager#FEATURE_IDENTITY_CREDENTIAL_HARDWARE for known feature versions.

setAllowUsingExhaustedKeys

abstract fun setAllowUsingExhaustedKeys(allowUsingExhaustedKeys: Boolean): Unit

Deprecated: Use PresentationSession instead.

Sets whether to allow using an authentication key which use count has been exceeded if no other key is available. This must be called prior to calling getEntries(byte[],java.util.Map,byte[],byte[]). By default this is set to true.

setAllowUsingExpiredKeys

open fun setAllowUsingExpiredKeys(allowUsingExpiredKeys: Boolean): Unit

Deprecated: Use PresentationSession instead.

Sets whether to allow using an authentication key which has been expired if no other key is available. This must be called prior to calling getEntries(byte[],java.util.Map,byte[],byte[]).

By default this is set to false.

This is only implemented in feature version 202101 or later. If not implemented, the call fails with UnsupportedOperationException. See android.content.pm.PackageManager#FEATURE_IDENTITY_CREDENTIAL_HARDWARE for known feature versions.

setAvailableAuthenticationKeys

abstract fun setAvailableAuthenticationKeys(
    keyCount: Int, 
    maxUsesPerKey: Int
): Unit

Deprecated: Use setAvailableAuthenticationKeys(int,int,long) instead.

Sets the number of dynamic authentication keys the IdentityCredential will maintain, and the number of times each should be used.

The Identity Credential system will select the least-used dynamic authentication key each time getEntries(byte[],java.util.Map,byte[],byte[]) is called. Identity Credentials for which this method has not been called behave as though it had been called wit keyCount 0 and maxUsesPerKey 1.

The effect of this method is like calling setAvailableAuthenticationKeys(int,int,long) with the last parameter is set to 0.

setAvailableAuthenticationKeys

open fun setAvailableAuthenticationKeys(
    keyCount: Int, 
    maxUsesPerKey: Int, 
    minValidTimeMillis: Long
): Unit

Sets the number of dynamic authentication keys the IdentityCredential will maintain, the number of times each should be used, and the minimum amount of time it's valid for.

The Identity Credential system will select the least-used dynamic authentication key each time getEntries(byte[],java.util.Map,byte[],byte[]) is called. Identity Credentials for which this method has not been called behave as though it had been called wit keyCount 0, maxUsesPerKey 1, and minValidTimeMillis 0.

Applications can use getAuthenticationKeyMetadata() to get a picture of the usage andtime left of each configured authentication key. This can be used to determine how urgent it is recertify new authentication keys via the getAuthKeysNeedingCertification() method.

setReaderEphemeralPublicKey

abstract fun setReaderEphemeralPublicKey(readerEphemeralPublicKey: PublicKey): Unit

Deprecated: Use PresentationSession instead.

Set the ephemeral public key provided by the reader. If called, this must be called before getEntries(byte[],java.util.Map,byte[],byte[]) is called.

storeStaticAuthenticationData

abstract fun storeStaticAuthenticationData(
    authenticationKey: X509Certificate, 
    staticAuthData: ByteArray
): Unit

Deprecated: Use storeStaticAuthenticationData(java.security.cert.X509Certificate,java.time.Instant,byte[]) instead.

Store authentication data associated with a dynamic authentication key. This should only be called for an authenticated key returned by getAuthKeysNeedingCertification().

storeStaticAuthenticationData

open fun storeStaticAuthenticationData(
    authenticationKey: X509Certificate, 
    expirationDate: Instant, 
    staticAuthData: ByteArray
): Unit

Store authentication data associated with a dynamic authentication key. This should only be called for an authenticated key returned by getAuthKeysNeedingCertification().

update

open fun update(personalizationData: PersonalizationData): ByteArray

Updates the credential with new access control profiles and data items.

This method is similar to WritableIdentityCredential#personalize(PersonalizationData) except that it operates on an existing credential, see the documentation for that method for the format of the returned data.

If this call succeeds an side-effect is that all dynamic authentication keys for the credential are deleted. The application will need to use getAuthKeysNeedingCertification() to generate replacement keys and return them for issuer certification.

This is only implemented in feature version 202101 or later. If not implemented, the call fails with UnsupportedOperationException. See android.content.pm.PackageManager#FEATURE_IDENTITY_CREDENTIAL_HARDWARE for known feature versions.