AndroidKeyStore: Add encrypted flag (2eeda728) · Commits · e / os / android_frameworks_base

api/current.txt

+20 −2

Original line number	Original line	Diff line number	Diff line
	@@ -20482,19 +20482,37 @@ package android.sax {

	package android.security {		package android.security {

	public class AndroidKeyPairGeneratorSpec implements java.security.spec.AlgorithmParameterSpec {		public final class AndroidKeyPairGeneratorSpec implements java.security.spec.AlgorithmParameterSpec {
			method public android.content.Context getContext();
			method public java.util.Date getEndDate();
			method public java.lang.String getKeystoreAlias();
			method public java.math.BigInteger getSerialNumber();
			method public java.util.Date getStartDate();
			method public javax.security.auth.x500.X500Principal getSubjectDN();
			method public boolean isEncryptionRequired();
	}		}

	public static class AndroidKeyPairGeneratorSpec.Builder {		public static final class AndroidKeyPairGeneratorSpec.Builder {
	ctor public AndroidKeyPairGeneratorSpec.Builder(android.content.Context);		ctor public AndroidKeyPairGeneratorSpec.Builder(android.content.Context);
	method public android.security.AndroidKeyPairGeneratorSpec build();		method public android.security.AndroidKeyPairGeneratorSpec build();
	method public android.security.AndroidKeyPairGeneratorSpec.Builder setAlias(java.lang.String);		method public android.security.AndroidKeyPairGeneratorSpec.Builder setAlias(java.lang.String);
			method public android.security.AndroidKeyPairGeneratorSpec.Builder setEncryptionRequired();
	method public android.security.AndroidKeyPairGeneratorSpec.Builder setEndDate(java.util.Date);		method public android.security.AndroidKeyPairGeneratorSpec.Builder setEndDate(java.util.Date);
	method public android.security.AndroidKeyPairGeneratorSpec.Builder setSerialNumber(java.math.BigInteger);		method public android.security.AndroidKeyPairGeneratorSpec.Builder setSerialNumber(java.math.BigInteger);
	method public android.security.AndroidKeyPairGeneratorSpec.Builder setStartDate(java.util.Date);		method public android.security.AndroidKeyPairGeneratorSpec.Builder setStartDate(java.util.Date);
	method public android.security.AndroidKeyPairGeneratorSpec.Builder setSubject(javax.security.auth.x500.X500Principal);		method public android.security.AndroidKeyPairGeneratorSpec.Builder setSubject(javax.security.auth.x500.X500Principal);
	}		}

			public final class AndroidKeyStoreParameter implements java.security.KeyStore.ProtectionParameter {
			method public boolean isEncryptionRequired();
			}

			public static final class AndroidKeyStoreParameter.Builder {
			ctor public AndroidKeyStoreParameter.Builder(android.content.Context);
			method public android.security.AndroidKeyStoreParameter build();
			method public android.security.AndroidKeyStoreParameter.Builder setEncryptionRequired();
			}

	public final class KeyChain {		public final class KeyChain {
	ctor public KeyChain();		ctor public KeyChain();
	method public static void choosePrivateKeyAlias(android.app.Activity, android.security.KeyChainAliasCallback, java.lang.String[], java.security.Principal[], java.lang.String, int, java.lang.String);		method public static void choosePrivateKeyAlias(android.app.Activity, android.security.KeyChainAliasCallback, java.lang.String[], java.security.Principal[], java.lang.String, int, java.lang.String);

keystore/java/android/security/AndroidKeyPairGenerator.java

+12 −5

Original line number	Original line	Diff line number	Diff line
	@@ -49,10 +49,7 @@ import java.security.spec.X509EncodedKeySpec;
	*		*
	* {@hide}		* {@hide}
	*/		*/
	@SuppressWarnings("deprecation")
	public class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {		public class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
	public static final String NAME = "AndroidKeyPairGenerator";

	private android.security.KeyStore mKeyStore;		private android.security.KeyStore mKeyStore;

	private AndroidKeyPairGeneratorSpec mSpec;		private AndroidKeyPairGeneratorSpec mSpec;
	@@ -79,12 +76,21 @@ public class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
	"Must call initialize with an AndroidKeyPairGeneratorSpec first");		"Must call initialize with an AndroidKeyPairGeneratorSpec first");
	}		}

			if (((mSpec.getFlags() & KeyStore.FLAG_ENCRYPTED) != 0)
			&& (mKeyStore.state() != KeyStore.State.UNLOCKED)) {
			throw new IllegalStateException(
			"Android keystore must be in initialized and unlocked state "
			+ "if encryption is required");
			}

	final String alias = mSpec.getKeystoreAlias();		final String alias = mSpec.getKeystoreAlias();

	Credentials.deleteAllTypesForAlias(mKeyStore, alias);		Credentials.deleteAllTypesForAlias(mKeyStore, alias);

	final String privateKeyAlias = Credentials.USER_PRIVATE_KEY + alias;		final String privateKeyAlias = Credentials.USER_PRIVATE_KEY + alias;
	mKeyStore.generate(privateKeyAlias);		if (!mKeyStore.generate(privateKeyAlias, KeyStore.UID_SELF, mSpec.getFlags())) {
			throw new IllegalStateException("could not generate key in keystore");
			}

	final PrivateKey privKey;		final PrivateKey privKey;
	final OpenSSLEngine engine = OpenSSLEngine.getInstance("keystore");		final OpenSSLEngine engine = OpenSSLEngine.getInstance("keystore");
	@@ -131,7 +137,8 @@ public class AndroidKeyPairGenerator extends KeyPairGeneratorSpi {
	throw new IllegalStateException("Can't get encoding of certificate", e);		throw new IllegalStateException("Can't get encoding of certificate", e);
	}		}

	if (!mKeyStore.put(Credentials.USER_CERTIFICATE + alias, certBytes)) {		if (!mKeyStore.put(Credentials.USER_CERTIFICATE + alias, certBytes, KeyStore.UID_SELF,
			mSpec.getFlags())) {
	Credentials.deleteAllTypesForAlias(mKeyStore, alias);		Credentials.deleteAllTypesForAlias(mKeyStore, alias);
	throw new IllegalStateException("Can't store certificate in AndroidKeyStore");		throw new IllegalStateException("Can't store certificate in AndroidKeyStore");
	}		}

keystore/java/android/security/AndroidKeyPairGeneratorSpec.java

+72 −29

Original line number	Original line	Diff line number	Diff line
	@@ -32,10 +32,9 @@ import javax.security.auth.x500.X500Principal;
	* {@code KeyPairGenerator} that works with <a href="{@docRoot}		* {@code KeyPairGenerator} that works with <a href="{@docRoot}
	* guide/topics/security/keystore.html">Android KeyStore facility</a>. The		* guide/topics/security/keystore.html">Android KeyStore facility</a>. The
	* Android KeyStore facility is accessed through a		* Android KeyStore facility is accessed through a
	* {@link java.security.KeyPairGenerator} API using the		* {@link java.security.KeyPairGenerator} API using the {@code AndroidKeyStore}
	* {@code AndroidKeyPairGenerator} provider. The {@code context} passed in may		* provider. The {@code context} passed in may be used to pop up some UI to ask
	* be used to pop up some UI to ask the user to unlock or initialize the Android		* the user to unlock or initialize the Android KeyStore facility.
	* keystore facility.
	* <p>		* <p>
	* After generation, the {@code keyStoreAlias} is used with the		* After generation, the {@code keyStoreAlias} is used with the
	* {@link java.security.KeyStore#getEntry(String, java.security.KeyStore.ProtectionParameter)}		* {@link java.security.KeyStore#getEntry(String, java.security.KeyStore.ProtectionParameter)}
	@@ -47,10 +46,10 @@ import javax.security.auth.x500.X500Principal;
	* Distinguished Name along with the other parameters specified with the		* Distinguished Name along with the other parameters specified with the
	* {@link Builder}.		* {@link Builder}.
	* <p>		* <p>
	* The self-signed certificate may be replaced at a later time by a certificate		* The self-signed X.509 certificate may be replaced at a later time by a
	* signed by a real Certificate Authority.		* certificate signed by a real Certificate Authority.
	*/		*/
	public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {		public final class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {
	private final String mKeystoreAlias;		private final String mKeystoreAlias;

	private final Context mContext;		private final Context mContext;
	@@ -63,6 +62,8 @@ public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {

	private final Date mEndDate;		private final Date mEndDate;

			private final int mFlags;

	/**		/**
	* Parameter specification for the "{@code AndroidKeyPairGenerator}"		* Parameter specification for the "{@code AndroidKeyPairGenerator}"
	* instance of the {@link java.security.KeyPairGenerator} API. The		* instance of the {@link java.security.KeyPairGenerator} API. The
	@@ -93,7 +94,8 @@ public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {
	* @hide should be built with AndroidKeyPairGeneratorSpecBuilder		* @hide should be built with AndroidKeyPairGeneratorSpecBuilder
	*/		*/
	public AndroidKeyPairGeneratorSpec(Context context, String keyStoreAlias,		public AndroidKeyPairGeneratorSpec(Context context, String keyStoreAlias,
	X500Principal subjectDN, BigInteger serialNumber, Date startDate, Date endDate) {		X500Principal subjectDN, BigInteger serialNumber, Date startDate, Date endDate,
			int flags) {
	if (context == null) {		if (context == null) {
	throw new IllegalArgumentException("context == null");		throw new IllegalArgumentException("context == null");
	} else if (TextUtils.isEmpty(keyStoreAlias)) {		} else if (TextUtils.isEmpty(keyStoreAlias)) {
	@@ -116,50 +118,71 @@ public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {
	mSerialNumber = serialNumber;		mSerialNumber = serialNumber;
	mStartDate = startDate;		mStartDate = startDate;
	mEndDate = endDate;		mEndDate = endDate;
			mFlags = flags;
	}		}

	/**		/**
	* @hide		* Returns the alias that will be used in the {@code java.security.KeyStore}
			* in conjunction with the {@code AndroidKeyStore}.
	*/		*/
	String getKeystoreAlias() {		public String getKeystoreAlias() {
	return mKeystoreAlias;		return mKeystoreAlias;
	}		}

	/**		/**
	* @hide		* Gets the Android context used for operations with this instance.
	*/		*/
	Context getContext() {		public Context getContext() {
	return mContext;		return mContext;
	}		}

	/**		/**
	* @hide		* Gets the subject distinguished name to be used on the X.509 certificate
			* that will be put in the {@link java.security.KeyStore}.
	*/		*/
	X500Principal getSubjectDN() {		public X500Principal getSubjectDN() {
	return mSubjectDN;		return mSubjectDN;
	}		}

	/**		/**
	* @hide		* Gets the serial number to be used on the X.509 certificate that will be
			* put in the {@link java.security.KeyStore}.
	*/		*/
	BigInteger getSerialNumber() {		public BigInteger getSerialNumber() {
	return mSerialNumber;		return mSerialNumber;
	}		}

	/**		/**
	* @hide		* Gets the start date to be used on the X.509 certificate that will be put
			* in the {@link java.security.KeyStore}.
	*/		*/
	Date getStartDate() {		public Date getStartDate() {
	return mStartDate;		return mStartDate;
	}		}

	/**		/**
	* @hide		* Gets the end date to be used on the X.509 certificate that will be put in
			* the {@link java.security.KeyStore}.
	*/		*/
	Date getEndDate() {		public Date getEndDate() {
	return mEndDate;		return mEndDate;
	}		}

			/**
			* @hide
			*/
			int getFlags() {
			return mFlags;
			}

			/**
			* Returns {@code true} if this parameter will require generated keys to be
			* encrypted in the {@link java.security.KeyStore}.
			*/
			public boolean isEncryptionRequired() {
			return (mFlags & KeyStore.FLAG_ENCRYPTED) != 0;
			}

	/**		/**
	* Builder class for {@link AndroidKeyPairGeneratorSpec} objects.		* Builder class for {@link AndroidKeyPairGeneratorSpec} objects.
	* <p>		* <p>
	@@ -175,16 +198,17 @@ public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {
	* Calendar end = new Calendar();		* Calendar end = new Calendar();
	* end.add(1, Calendar.YEAR);		* end.add(1, Calendar.YEAR);
	*		*
	* AndroidKeyPairGeneratorSpec spec = new AndroidKeyPairGeneratorSpec.Builder(mContext)		* AndroidKeyPairGeneratorSpec spec =
	* .setAlias("myKey")		* new AndroidKeyPairGeneratorSpec.Builder(mContext)
	* .setSubject(new X500Principal("CN=myKey"))		* .setAlias("myKey")
			* .setSubject(new X500Principal("CN=myKey"))
	* .setSerial(BigInteger.valueOf(1337))		* .setSerial(BigInteger.valueOf(1337))
	* .setStartDate(start.getTime())		* .setStartDate(start.getTime())
	* .setEndDate(end.getTime())		* .setEndDate(end.getTime())
	* .build();		* .build();
	* </pre>		* </pre>
	*/		*/
	public static class Builder {		public final static class Builder {
	private final Context mContext;		private final Context mContext;

	private String mKeystoreAlias;		private String mKeystoreAlias;
	@@ -197,6 +221,14 @@ public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {

	private Date mEndDate;		private Date mEndDate;

			private int mFlags;

			/**
			* Creates a new instance of the {@code Builder} with the given
			* {@code context}. The {@code context} passed in may be used to pop up
			* some UI to ask the user to unlock or initialize the Android KeyStore
			* facility.
			*/
	public Builder(Context context) {		public Builder(Context context) {
	if (context == null) {		if (context == null) {
	throw new NullPointerException("context == null");		throw new NullPointerException("context == null");
	@@ -265,6 +297,17 @@ public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {
	return this;		return this;
	}		}

			/**
			* Indicates that this key must be encrypted at rest on storage. Note
			* that enabling this will require that the user enable a strong lock
			* screen (e.g., PIN, password) before creating or using the generated
			* key is successful.
			*/
			public Builder setEncryptionRequired() {
			mFlags \|= KeyStore.FLAG_ENCRYPTED;
			return this;
			}

	/**		/**
	* Builds the instance of the {@code AndroidKeyPairGeneratorSpec}.		* Builds the instance of the {@code AndroidKeyPairGeneratorSpec}.
	*		*
	@@ -273,7 +316,7 @@ public class AndroidKeyPairGeneratorSpec implements AlgorithmParameterSpec {
	*/		*/
	public AndroidKeyPairGeneratorSpec build() {		public AndroidKeyPairGeneratorSpec build() {
	return new AndroidKeyPairGeneratorSpec(mContext, mKeystoreAlias, mSubjectDN,		return new AndroidKeyPairGeneratorSpec(mContext, mKeystoreAlias, mSubjectDN,
	mSerialNumber, mStartDate, mEndDate);		mSerialNumber, mStartDate, mEndDate, mFlags);
	}		}
	}		}
	}		}

keystore/java/android/security/AndroidKeyStore.java

+50 −7

Original line number	Original line	Diff line number	Diff line
	@@ -27,6 +27,10 @@ import java.io.InputStream;
	import java.io.OutputStream;		import java.io.OutputStream;
	import java.security.InvalidKeyException;		import java.security.InvalidKeyException;
	import java.security.Key;		import java.security.Key;
			import java.security.KeyStore.Entry;
			import java.security.KeyStore.PrivateKeyEntry;
			import java.security.KeyStore.ProtectionParameter;
			import java.security.KeyStore;
	import java.security.KeyStoreException;		import java.security.KeyStoreException;
	import java.security.KeyStoreSpi;		import java.security.KeyStoreSpi;
	import java.security.NoSuchAlgorithmException;		import java.security.NoSuchAlgorithmException;
	@@ -198,14 +202,14 @@ public class AndroidKeyStore extends KeyStoreSpi {
	}		}

	if (key instanceof PrivateKey) {		if (key instanceof PrivateKey) {
	setPrivateKeyEntry(alias, (PrivateKey) key, chain);		setPrivateKeyEntry(alias, (PrivateKey) key, chain, null);
	} else {		} else {
	throw new KeyStoreException("Only PrivateKeys are supported");		throw new KeyStoreException("Only PrivateKeys are supported");
	}		}
	}		}

	private void setPrivateKeyEntry(String alias, PrivateKey key, Certificate[] chain)		private void setPrivateKeyEntry(String alias, PrivateKey key, Certificate[] chain,
	throws KeyStoreException {		AndroidKeyStoreParameter params) throws KeyStoreException {
	byte[] keyBytes = null;		byte[] keyBytes = null;

	final String pkeyAlias;		final String pkeyAlias;
	@@ -317,15 +321,20 @@ public class AndroidKeyStore extends KeyStoreSpi {
	Credentials.deleteCertificateTypesForAlias(mKeyStore, alias);		Credentials.deleteCertificateTypesForAlias(mKeyStore, alias);
	}		}

			final int flags = (params == null) ? 0 : params.getFlags();

	if (shouldReplacePrivateKey		if (shouldReplacePrivateKey
	&& !mKeyStore.importKey(Credentials.USER_PRIVATE_KEY + alias, keyBytes)) {		&& !mKeyStore.importKey(Credentials.USER_PRIVATE_KEY + alias, keyBytes,
			android.security.KeyStore.UID_SELF, flags)) {
	Credentials.deleteAllTypesForAlias(mKeyStore, alias);		Credentials.deleteAllTypesForAlias(mKeyStore, alias);
	throw new KeyStoreException("Couldn't put private key in keystore");		throw new KeyStoreException("Couldn't put private key in keystore");
	} else if (!mKeyStore.put(Credentials.USER_CERTIFICATE + alias, userCertBytes)) {		} else if (!mKeyStore.put(Credentials.USER_CERTIFICATE + alias, userCertBytes,
			android.security.KeyStore.UID_SELF, flags)) {
	Credentials.deleteAllTypesForAlias(mKeyStore, alias);		Credentials.deleteAllTypesForAlias(mKeyStore, alias);
	throw new KeyStoreException("Couldn't put certificate #1 in keystore");		throw new KeyStoreException("Couldn't put certificate #1 in keystore");
	} else if (chainBytes != null		} else if (chainBytes != null
	&& !mKeyStore.put(Credentials.CA_CERTIFICATE + alias, chainBytes)) {		&& !mKeyStore.put(Credentials.CA_CERTIFICATE + alias, chainBytes,
			android.security.KeyStore.UID_SELF, flags)) {
	Credentials.deleteAllTypesForAlias(mKeyStore, alias);		Credentials.deleteAllTypesForAlias(mKeyStore, alias);
	throw new KeyStoreException("Couldn't put certificate chain in keystore");		throw new KeyStoreException("Couldn't put certificate chain in keystore");
	}		}
	@@ -355,7 +364,8 @@ public class AndroidKeyStore extends KeyStoreSpi {
	throw new KeyStoreException(e);		throw new KeyStoreException(e);
	}		}

	if (!mKeyStore.put(Credentials.CA_CERTIFICATE + alias, encoded)) {		if (!mKeyStore.put(Credentials.CA_CERTIFICATE + alias, encoded,
			android.security.KeyStore.UID_SELF, android.security.KeyStore.FLAG_NONE)) {
	throw new KeyStoreException("Couldn't insert certificate; is KeyStore initialized?");		throw new KeyStoreException("Couldn't insert certificate; is KeyStore initialized?");
	}		}
	}		}
	@@ -517,4 +527,37 @@ public class AndroidKeyStore extends KeyStoreSpi {
	mKeyStore = android.security.KeyStore.getInstance();		mKeyStore = android.security.KeyStore.getInstance();
	}		}

			@Override
			public void engineSetEntry(String alias, Entry entry, ProtectionParameter param)
			throws KeyStoreException {
			if (entry == null) {
			throw new KeyStoreException("entry == null");
			}

			if (engineContainsAlias(alias)) {
			engineDeleteEntry(alias);
			}

			if (entry instanceof KeyStore.TrustedCertificateEntry) {
			KeyStore.TrustedCertificateEntry trE = (KeyStore.TrustedCertificateEntry) entry;
			engineSetCertificateEntry(alias, trE.getTrustedCertificate());
			return;
			}

			if (param != null && !(param instanceof AndroidKeyStoreParameter)) {
			throw new KeyStoreException("protParam should be AndroidKeyStoreParameter; was: "
			+ param.getClass().getName());
			}

			if (entry instanceof PrivateKeyEntry) {
			PrivateKeyEntry prE = (PrivateKeyEntry) entry;
			setPrivateKeyEntry(alias, prE.getPrivateKey(), prE.getCertificateChain(),
			(AndroidKeyStoreParameter) param);
			return;
			}

			throw new KeyStoreException(
			"Entry must be a PrivateKeyEntry or TrustedCertificateEntry; was " + entry);
			}

	}		}

keystore/java/android/security/AndroidKeyStoreParameter.java

0 → 100644

+123 −0

Original line number	Original line	Diff line number	Diff line
			/*
			* Copyright (C) 2013 The Android Open Source Project
			*
			* Licensed under the Apache License, Version 2.0 (the "License");
			* you may not use this file except in compliance with the License.
			* You may obtain a copy of the License at
			*
			* http://www.apache.org/licenses/LICENSE-2.0
			*
			* Unless required by applicable law or agreed to in writing, software
			* distributed under the License is distributed on an "AS IS" BASIS,
			* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
			* See the License for the specific language governing permissions and
			* limitations under the License.
			*/

			package android.security;

			import android.content.Context;
			import android.security.AndroidKeyPairGeneratorSpec.Builder;

			import java.security.KeyPairGenerator;
			import java.security.PrivateKey;
			import java.security.KeyStore.ProtectionParameter;
			import java.security.cert.Certificate;

			/**
			* This provides the optional parameters that can be specified for
			* {@code KeyStore} entries that work with <a href="{@docRoot}
			* guide/topics/security/keystore.html">Android KeyStore facility</a>. The
			* Android KeyStore facility is accessed through a
			* {@link java.security.KeyStore} API using the {@code AndroidKeyStore}
			* provider. The {@code context} passed in may be used to pop up some UI to ask
			* the user to unlock or initialize the Android KeyStore facility.
			* <p>
			* Any entries placed in the {@code KeyStore} may be retrieved later. Note that
			* there is only one logical instance of the {@code KeyStore} per application
			* UID so apps using the {@code sharedUid} facility will also share a
			* {@code KeyStore}.
			* <p>
			* Keys may be generated using the {@link KeyPairGenerator} facility with a
			* {@link AndroidKeyPairGeneratorSpec} to specify the entry's {@code alias}. A
			* self-signed X.509 certificate will be attached to generated entries, but that
			* may be replaced at a later time by a certificate signed by a real Certificate
			* Authority.
			*/
			public final class AndroidKeyStoreParameter implements ProtectionParameter {
			private int mFlags;

			private AndroidKeyStoreParameter(int flags) {
			mFlags = flags;
			}

			/**
			* @hide
			*/
			public int getFlags() {
			return mFlags;
			}

			/**
			* Returns {@code true} if this parameter requires entries to be encrypted
			* on the disk.
			*/
			public boolean isEncryptionRequired() {
			return (mFlags & KeyStore.FLAG_ENCRYPTED) != 0;
			}

			/**
			* Builder class for {@link AndroidKeyStoreParameter} objects.
			* <p>
			* This will build protection parameters for use with the <a
			* href="{@docRoot} guide/topics/security/keystore.html">Android KeyStore
			* facility</a>.
			* <p>
			* This can be used to require that KeyStore entries be stored encrypted.
			* <p>
			* Example:
			*
			* <pre class="prettyprint">
			* AndroidKeyStoreParameter params =
			* new AndroidKeyStoreParameter.Builder(mContext).setEncryptionRequired().build();
			* </pre>
			*/
			public final static class Builder {
			private int mFlags;

			/**
			* Creates a new instance of the {@code Builder} with the given
			* {@code context}. The {@code context} passed in may be used to pop up
			* some UI to ask the user to unlock or initialize the Android KeyStore
			* facility.
			*/
			public Builder(Context context) {
			if (context == null) {
			throw new NullPointerException("context == null");
			}

			// Context is currently not used, but will be in the future.
			}

			/**
			* Indicates that this key must be encrypted at rest on storage. Note
			* that enabling this will require that the user enable a strong lock
			* screen (e.g., PIN, password) before creating or using the generated
			* key is successful.
			*/
			public Builder setEncryptionRequired() {
			mFlags \|= KeyStore.FLAG_ENCRYPTED;
			return this;
			}

			/**
			* Builds the instance of the {@code AndroidKeyPairGeneratorSpec}.
			*
			* @throws IllegalArgumentException if a required field is missing
			* @return built instance of {@code AndroidKeyPairGeneratorSpec}
			*/
			public AndroidKeyStoreParameter build() {
			return new AndroidKeyStoreParameter(mFlags);
			}
			}
			}