Applications accessing the {@code KeyChain} normally go through * these steps: * *
An application may remember the value of a selected alias to * avoid prompting the user with {@link #choosePrivateKeyAlias * choosePrivateKeyAlias} on subsequent connections. If the alias is * no longer valid, null will be returned on lookups using that value * *
An application can request the installation of private keys and * certificates via the {@code Intent} provided by {@link * #createInstallIntent}. Private keys installed via this {@code * Intent} will be accessible via {@link #choosePrivateKeyAlias} while * Certificate Authority (CA) certificates will be trusted by all * applications through the default {@code X509TrustManager}. */ // TODO reference intent for credential installation when public public final class KeyChain { /** * @hide Also used by KeyChainService implementation */ public static final String ACCOUNT_TYPE = "com.android.keychain"; /** * Package name for KeyChain chooser. */ private static final String KEYCHAIN_PACKAGE = "com.android.keychain"; /** * Action to bring up the KeyChainActivity */ private static final String ACTION_CHOOSER = "com.android.keychain.CHOOSER"; /** * Package name for the Certificate Installer. */ private static final String CERT_INSTALLER_PACKAGE = "com.android.certinstaller"; /** * Extra for use with {@link #ACTION_CHOOSER} * @hide Also used by KeyChainActivity implementation */ public static final String EXTRA_RESPONSE = "response"; /** * Extra for use with {@link #ACTION_CHOOSER} * @hide Also used by KeyChainActivity implementation */ public static final String EXTRA_URI = "uri"; /** * Extra for use with {@link #ACTION_CHOOSER} * @hide Also used by KeyChainActivity implementation */ public static final String EXTRA_ALIAS = "alias"; /** * Extra for use with {@link #ACTION_CHOOSER} * @hide Also used by KeyChainActivity implementation */ public static final String EXTRA_SENDER = "sender"; /** * Action to bring up the CertInstaller. */ private static final String ACTION_INSTALL = "android.credentials.INSTALL"; /** * Optional extra to specify a {@code String} credential name on * the {@code Intent} returned by {@link #createInstallIntent}. */ // Compatible with old com.android.certinstaller.CredentialHelper.CERT_NAME_KEY public static final String EXTRA_NAME = "name"; /** * Optional extra to specify an X.509 certificate to install on * the {@code Intent} returned by {@link #createInstallIntent}. * The extra value should be a PEM or ASN.1 DER encoded {@code * byte[]}. An {@link X509Certificate} can be converted to DER * encoded bytes with {@link X509Certificate#getEncoded}. * *
{@link #EXTRA_NAME} may be used to provide a default alias * name for the installed certificate. */ // Compatible with old android.security.Credentials.CERTIFICATE public static final String EXTRA_CERTIFICATE = "CERT"; /** * Optional extra for use with the {@code Intent} returned by * {@link #createInstallIntent} to specify a PKCS#12 key store to * install. The extra value should be a {@code byte[]}. The bytes * may come from an external source or be generated with {@link * java.security.KeyStore#store} on a "PKCS12" instance. * *
The user will be prompted for the password to load the key store. * *
The key store will be scanned for {@link * java.security.KeyStore.PrivateKeyEntry} entries and both the * private key and associated certificate chain will be installed. * *
{@link #EXTRA_NAME} may be used to provide a default alias * name for the installed credentials. */ // Compatible with old android.security.Credentials.PKCS12 public static final String EXTRA_PKCS12 = "PKCS12"; /** * Broadcast Action: Indicates the trusted storage has changed. Sent when * one of this happens: * *
Alternatively, {@link #EXTRA_CERTIFICATE} or {@link * #EXTRA_PKCS12} maybe used to specify the bytes of an X.509 * certificate or a PKCS#12 key store for installation. These * extras may be combined with {@link #EXTRA_NAME} to provide a * default alias name for credentials being installed. * *
When used with {@link Activity#startActivityForResult}, * {@link Activity#RESULT_OK} will be returned if a credential was * successfully installed, otherwise {@link * Activity#RESULT_CANCELED} will be returned. */ @NonNull public static Intent createInstallIntent() { Intent intent = new Intent(ACTION_INSTALL); intent.setClassName(CERT_INSTALLER_PACKAGE, "com.android.certinstaller.CertInstallerMain"); return intent; } /** * Launches an {@code Activity} for the user to select the alias * for a private key and certificate pair for authentication. The * selected alias or null will be returned via the * KeyChainAliasCallback callback. * *
The device or profile owner can intercept this before the activity * is shown, to pick a specific private key alias. * *
{@code keyTypes} and {@code issuers} may be used to * highlight suggested choices to the user, although to cope with * sometimes erroneous values provided by servers, the user may be * able to override these suggestions. * *
{@code host} and {@code port} may be used to give the user * more context about the server requesting the credentials. * *
{@code alias} allows the chooser to preselect an existing * alias which will still be subject to user confirmation. * * @param activity The {@link Activity} context to use for * launching the new sub-Activity to prompt the user to select * a private key; used only to call startActivity(); must not * be null. * @param response Callback to invoke when the request completes; * must not be null * @param keyTypes The acceptable types of asymmetric keys such as * "RSA" or "DSA", or a null array. * @param issuers The acceptable certificate issuers for the * certificate matching the private key, or null. * @param host The host name of the server requesting the * certificate, or null if unavailable. * @param port The port number of the server requesting the * certificate, or -1 if unavailable. * @param alias The alias to preselect if available, or null if * unavailable. */ public static void choosePrivateKeyAlias(@NonNull Activity activity, @NonNull KeyChainAliasCallback response, @KeyProperties.KeyAlgorithmEnum String[] keyTypes, Principal[] issuers, @Nullable String host, int port, @Nullable String alias) { Uri uri = null; if (host != null) { uri = new Uri.Builder() .authority(host + (port != -1 ? ":" + port : "")) .build(); } choosePrivateKeyAlias(activity, response, keyTypes, issuers, uri, alias); } /** * Launches an {@code Activity} for the user to select the alias * for a private key and certificate pair for authentication. The * selected alias or null will be returned via the * KeyChainAliasCallback callback. * *
The device or profile owner can intercept this before the activity * is shown, to pick a specific private key alias.
* *{@code keyTypes} and {@code issuers} may be used to * highlight suggested choices to the user, although to cope with * sometimes erroneous values provided by servers, the user may be * able to override these suggestions. * *
{@code host} and {@code port} may be used to give the user * more context about the server requesting the credentials. * *
{@code alias} allows the chooser to preselect an existing * alias which will still be subject to user confirmation. * * @param activity The {@link Activity} context to use for * launching the new sub-Activity to prompt the user to select * a private key; used only to call startActivity(); must not * be null. * @param response Callback to invoke when the request completes; * must not be null * @param keyTypes The acceptable types of asymmetric keys such as * "EC" or "RSA", or a null array. * @param issuers The acceptable certificate issuers for the * certificate matching the private key, or null. * @param uri The full URI the server is requesting the certificate * for, or null if unavailable. * @param alias The alias to preselect if available, or null if * unavailable. */ public static void choosePrivateKeyAlias(@NonNull Activity activity, @NonNull KeyChainAliasCallback response, @KeyProperties.KeyAlgorithmEnum String[] keyTypes, Principal[] issuers, @Nullable Uri uri, @Nullable String alias) { /* * TODO currently keyTypes, issuers are unused. They are meant * to follow the semantics and purpose of X509KeyManager * method arguments. * * keyTypes would allow the list to be filtered and typically * will be set correctly by the server. In practice today, * most all users will want only RSA or EC, and usually * only a small number of certs will be available. * * issuers is typically not useful. Some servers historically * will send the entire list of public CAs known to the * server. Others will send none. If this is used, if there * are no matches after applying the constraint, it should be * ignored. */ if (activity == null) { throw new NullPointerException("activity == null"); } if (response == null) { throw new NullPointerException("response == null"); } Intent intent = new Intent(ACTION_CHOOSER); intent.setPackage(KEYCHAIN_PACKAGE); intent.putExtra(EXTRA_RESPONSE, new AliasResponse(response)); intent.putExtra(EXTRA_URI, uri); intent.putExtra(EXTRA_ALIAS, alias); // the PendingIntent is used to get calling package name intent.putExtra(EXTRA_SENDER, PendingIntent.getActivity(activity, 0, new Intent(), 0)); activity.startActivity(intent); } private static class AliasResponse extends IKeyChainAliasCallback.Stub { private final KeyChainAliasCallback keyChainAliasResponse; private AliasResponse(KeyChainAliasCallback keyChainAliasResponse) { this.keyChainAliasResponse = keyChainAliasResponse; } @Override public void alias(String alias) { keyChainAliasResponse.alias(alias); } } /** * Returns the {@code PrivateKey} for the requested alias, or null * if there is no result. * *
This method may block while waiting for a connection to another process, and must never * be called from the main thread. * * @param alias The alias of the desired private key, typically returned via * {@link KeyChainAliasCallback#alias}. * @throws KeyChainException if the alias was valid but there was some problem accessing it. * @throws IllegalStateException if called from the main thread. */ @Nullable @WorkerThread public static PrivateKey getPrivateKey(@NonNull Context context, @NonNull String alias) throws KeyChainException, InterruptedException { if (alias == null) { throw new NullPointerException("alias == null"); } KeyChainConnection keyChainConnection = bind(context); try { final IKeyChainService keyChainService = keyChainConnection.getService(); final String keyId = keyChainService.requestPrivateKey(alias); if (keyId == null) { return null; } return AndroidKeyStoreProvider.loadAndroidKeyStorePrivateKeyFromKeystore( KeyStore.getInstance(), keyId, KeyStore.UID_SELF); } catch (RemoteException e) { throw new KeyChainException(e); } catch (RuntimeException e) { // only certain RuntimeExceptions can be propagated across the IKeyChainService call throw new KeyChainException(e); } catch (UnrecoverableKeyException e) { throw new KeyChainException(e); } finally { keyChainConnection.close(); } } /** * Returns the {@code X509Certificate} chain for the requested * alias, or null if there is no result. *
* Note: If a certificate chain was explicitly specified when the alias was * installed, this method will return that chain. If only the client certificate was specified * at the installation time, this method will try to build a certificate chain using all * available trust anchors (preinstalled and user-added). * *
This method may block while waiting for a connection to another process, and must never
* be called from the main thread.
*
* @param alias The alias of the desired certificate chain, typically
* returned via {@link KeyChainAliasCallback#alias}.
* @throws KeyChainException if the alias was valid but there was some problem accessing it.
* @throws IllegalStateException if called from the main thread.
*/
@Nullable @WorkerThread
public static X509Certificate[] getCertificateChain(@NonNull Context context,
@NonNull String alias) throws KeyChainException, InterruptedException {
if (alias == null) {
throw new NullPointerException("alias == null");
}
KeyChainConnection keyChainConnection = bind(context);
try {
IKeyChainService keyChainService = keyChainConnection.getService();
final byte[] certificateBytes = keyChainService.getCertificate(alias);
if (certificateBytes == null) {
return null;
}
X509Certificate leafCert = toCertificate(certificateBytes);
final byte[] certChainBytes = keyChainService.getCaCertificates(alias);
// If the keypair is installed with a certificate chain by either
// DevicePolicyManager.installKeyPair or CertInstaller, return that chain.
if (certChainBytes != null && certChainBytes.length != 0) {
Collection{@code
* PrivateKey key = ...; // private key from KeyChain
*
* KeyFactory keyFactory =
* KeyFactory.getInstance(key.getAlgorithm(), "AndroidKeyStore");
* KeyInfo keyInfo = keyFactory.getKeySpec(key, KeyInfo.class);
* if (keyInfo.isInsideSecureHardware()) {
* // The key is bound to the secure hardware of this Android
* }}
*/
@Deprecated
public static boolean isBoundKeyAlgorithm(
@NonNull @KeyProperties.KeyAlgorithmEnum String algorithm) {
if (!isKeyAlgorithmSupported(algorithm)) {
return false;
}
return KeyStore.getInstance().isHardwareBacked(algorithm);
}
/** @hide */
@NonNull
public static X509Certificate toCertificate(@NonNull byte[] bytes) {
if (bytes == null) {
throw new IllegalArgumentException("bytes == null");
}
try {
CertificateFactory certFactory = CertificateFactory.getInstance("X.509");
Certificate cert = certFactory.generateCertificate(new ByteArrayInputStream(bytes));
return (X509Certificate) cert;
} catch (CertificateException e) {
throw new AssertionError(e);
}
}
/** @hide */
@NonNull
public static Collection