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/*
* Copyright (C) 2012 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.text.TextUtils;
import java.math.BigInteger;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.cert.Certificate;
import java.security.spec.AlgorithmParameterSpec;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import javax.security.auth.x500.X500Principal;
/**
* This provides the required parameters needed for initializing the
* {@code KeyPairGenerator} that works with
* <a href="{@docRoot}training/articles/keystore.html">Android KeyStore
* facility</a>. The Android KeyStore facility is accessed through a
* {@link java.security.KeyPairGenerator} 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>
* After generation, the {@code keyStoreAlias} is used with the
* {@link java.security.KeyStore#getEntry(String, java.security.KeyStore.ProtectionParameter)}
* interface to retrieve the {@link PrivateKey} and its associated
* {@link Certificate} chain.
* <p>
* The KeyPair generator will create a self-signed certificate with the subject
* as its X.509v3 Subject Distinguished Name and as its X.509v3 Issuer
* Distinguished Name along with the other parameters specified with the
* {@link Builder}.
* <p>
* The self-signed X.509 certificate may be replaced at a later time by a
* certificate signed by a real Certificate Authority.
*/
public final class KeyPairGeneratorSpec implements AlgorithmParameterSpec {
private final Context mContext;
private final String mKeystoreAlias;
private final String mKeyType;
private final int mKeySize;
private final AlgorithmParameterSpec mSpec;
private final X500Principal mSubjectDN;
private final BigInteger mSerialNumber;
private final Date mStartDate;
private final Date mEndDate;
private final int mFlags;
private final Date mKeyValidityStart;
private final Date mKeyValidityForOriginationEnd;
private final Date mKeyValidityForConsumptionEnd;
private final @KeyStoreKeyConstraints.PurposeEnum Integer mPurposes;
private final @KeyStoreKeyConstraints.DigestEnum Integer mDigest;
private final @KeyStoreKeyConstraints.PaddingEnum Integer mPadding;
private final @KeyStoreKeyConstraints.BlockModeEnum Integer mBlockMode;
private final Integer mMinSecondsBetweenOperations;
private final Integer mMaxUsesPerBoot;
private final Set<Integer> mUserAuthenticators;
private final Integer mUserAuthenticationValidityDurationSeconds;
/**
* Parameter specification for the "{@code AndroidKeyPairGenerator}"
* instance of the {@link java.security.KeyPairGenerator} API. 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>
* After generation, the {@code keyStoreAlias} is used with the
* {@link java.security.KeyStore#getEntry(String, java.security.KeyStore.ProtectionParameter)}
* interface to retrieve the {@link PrivateKey} and its associated
* {@link Certificate} chain.
* <p>
* The KeyPair generator will create a self-signed certificate with the
* properties of {@code subjectDN} as its X.509v3 Subject Distinguished Name
* and as its X.509v3 Issuer Distinguished Name, using the specified
* {@code serialNumber}, and the validity date starting at {@code startDate}
* and ending at {@code endDate}.
*
* @param context Android context for the activity
* @param keyStoreAlias name to use for the generated key in the Android
* keystore
* @param keyType key algorithm to use (EC, RSA)
* @param keySize size of key to generate
* @param spec the underlying key type parameters
* @param subjectDN X.509 v3 Subject Distinguished Name
* @param serialNumber X509 v3 certificate serial number
* @param startDate the start of the self-signed certificate validity period
* @param endDate the end date of the self-signed certificate validity
* period
* @throws IllegalArgumentException when any argument is {@code null} or
* {@code endDate} is before {@code startDate}.
* @hide should be built with KeyPairGeneratorSpecBuilder
*/
public KeyPairGeneratorSpec(Context context, String keyStoreAlias, String keyType, int keySize,
AlgorithmParameterSpec spec, X500Principal subjectDN, BigInteger serialNumber,
Date startDate, Date endDate, int flags,
Date keyValidityStart,
Date keyValidityForOriginationEnd,
Date keyValidityForConsumptionEnd,
@KeyStoreKeyConstraints.PurposeEnum Integer purposes,
@KeyStoreKeyConstraints.DigestEnum Integer digest,
@KeyStoreKeyConstraints.PaddingEnum Integer padding,
@KeyStoreKeyConstraints.BlockModeEnum Integer blockMode,
Integer minSecondsBetweenOperations,
Integer maxUsesPerBoot,
Set<Integer> userAuthenticators,
Integer userAuthenticationValidityDurationSeconds) {
if (context == null) {
throw new IllegalArgumentException("context == null");
} else if (TextUtils.isEmpty(keyStoreAlias)) {
throw new IllegalArgumentException("keyStoreAlias must not be empty");
} else if (subjectDN == null) {
throw new IllegalArgumentException("subjectDN == null");
} else if (serialNumber == null) {
throw new IllegalArgumentException("serialNumber == null");
} else if (startDate == null) {
throw new IllegalArgumentException("startDate == null");
} else if (endDate == null) {
throw new IllegalArgumentException("endDate == null");
} else if (endDate.before(startDate)) {
throw new IllegalArgumentException("endDate < startDate");
} else if ((userAuthenticationValidityDurationSeconds != null)
&& (userAuthenticationValidityDurationSeconds < 0)) {
throw new IllegalArgumentException(
"userAuthenticationValidityDurationSeconds must not be negative");
}
mContext = context;
mKeystoreAlias = keyStoreAlias;
mKeyType = keyType;
mKeySize = keySize;
mSpec = spec;
mSubjectDN = subjectDN;
mSerialNumber = serialNumber;
mStartDate = startDate;
mEndDate = endDate;
mFlags = flags;
mKeyValidityStart = keyValidityStart;
mKeyValidityForOriginationEnd = keyValidityForOriginationEnd;
mKeyValidityForConsumptionEnd = keyValidityForConsumptionEnd;
mPurposes = purposes;
mDigest = digest;
mPadding = padding;
mBlockMode = blockMode;
mMinSecondsBetweenOperations = minSecondsBetweenOperations;
mMaxUsesPerBoot = maxUsesPerBoot;
mUserAuthenticators = (userAuthenticators != null)
? new HashSet<Integer>(userAuthenticators)
: Collections.<Integer>emptySet();
mUserAuthenticationValidityDurationSeconds = userAuthenticationValidityDurationSeconds;
}
/**
* TODO: Remove this constructor once tests are switched over to the new one above.
* @hide
*/
public KeyPairGeneratorSpec(Context context, String keyStoreAlias, String keyType, int keySize,
AlgorithmParameterSpec spec, X500Principal subjectDN, BigInteger serialNumber,
Date startDate, Date endDate, int flags) {
this(context, keyStoreAlias, keyType, keySize, spec, subjectDN, serialNumber, startDate,
endDate, flags, startDate, endDate, endDate, null, null, null, null, null, null,
null, null);
}
/**
* Gets the Android context used for operations with this instance.
*/
public Context getContext() {
return mContext;
}
/**
* Returns the alias that will be used in the {@code java.security.KeyStore}
* in conjunction with the {@code AndroidKeyStore}.
*/
public String getKeystoreAlias() {
return mKeystoreAlias;
}
/**
* Returns the key type (e.g., "EC", "RSA") specified by this parameter.
*/
public String getKeyType() {
return mKeyType;
}
/**
* Returns the key size specified by this parameter. For instance, for RSA
* this will return the modulus size and for EC it will return the field
* size.
*/
public int getKeySize() {
return mKeySize;
}
/**
* Returns the {@link AlgorithmParameterSpec} that will be used for creation
* of the key pair.
*/
public AlgorithmParameterSpec getAlgorithmParameterSpec() {
return mSpec;
}
/**
* Gets the subject distinguished name to be used on the X.509 certificate
* that will be put in the {@link java.security.KeyStore}.
*/
public X500Principal getSubjectDN() {
return mSubjectDN;
}
/**
* Gets the serial number to be used on the X.509 certificate that will be
* put in the {@link java.security.KeyStore}.
*/
public BigInteger getSerialNumber() {
return mSerialNumber;
}
/**
* Gets the start date to be used on the X.509 certificate that will be put
* in the {@link java.security.KeyStore}.
*/
public Date getStartDate() {
return mStartDate;
}
/**
* Gets the end date to be used on the X.509 certificate that will be put in
* the {@link java.security.KeyStore}.
*/
public Date getEndDate() {
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;
}
/**
* Gets the time instant before which the key pair is not yet valid.
*
* @return instant or {@code null} if not restricted.
*
* @hide
*/
public Date getKeyValidityStart() {
return mKeyValidityStart;
}
/**
* Gets the time instant after which the key pair is no longer valid for decryption and
* verification.
*
* @return instant or {@code null} if not restricted.
*
* @hide
*/
public Date getKeyValidityForConsumptionEnd() {
return mKeyValidityForConsumptionEnd;
}
/**
* Gets the time instant after which the key pair is no longer valid for encryption and signing.
*
* @return instant or {@code null} if not restricted.
*
* @hide
*/
public Date getKeyValidityForOriginationEnd() {
return mKeyValidityForOriginationEnd;
}
/**
* Gets the set of purposes for which the key can be used.
*
* @return set of purposes or {@code null} if the key can be used for any purpose.
*
* @hide
*/
public @KeyStoreKeyConstraints.PurposeEnum Integer getPurposes() {
return mPurposes;
}
/**
* Gets the digest to which the key is restricted.
*
* @return digest or {@code null} if the digest is not restricted.
*
* @hide
*/
public @KeyStoreKeyConstraints.DigestEnum Integer getDigest() {
return mDigest;
}
/**
* Gets the padding scheme to which the key is restricted.
*
* @return padding scheme or {@code null} if the padding scheme is not restricted.
*
* @hide
*/
public @KeyStoreKeyConstraints.PaddingEnum Integer getPadding() {
return mPadding;
}
/**
* Gets the block mode to which the key is restricted when used for encryption or decryption.
*
* @return block more or {@code null} if block mode is not restricted.
*
* @hide
*/
public @KeyStoreKeyConstraints.BlockModeEnum Integer getBlockMode() {
return mBlockMode;
}
/**
* Gets the minimum number of seconds that must expire since the most recent use of the private
* key before it can be used again.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @return number of seconds or {@code null} if there is no restriction on how frequently a key
* can be used.
*
* @hide
*/
public Integer getMinSecondsBetweenOperations() {
return mMinSecondsBetweenOperations;
}
/**
* Gets the number of times the private key can be used without rebooting the device.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @return maximum number of times or {@code null} if there is no restriction.
*
* @hide
*/
public Integer getMaxUsesPerBoot() {
return mMaxUsesPerBoot;
}
/**
* Gets the user authenticators which protect access to the private key. The key can only be
* used iff the user has authenticated to at least one of these user authenticators.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @return user authenticators or empty set if the key can be used without user authentication.
*
* @hide
*/
public Set<Integer> getUserAuthenticators() {
return new HashSet<Integer>(mUserAuthenticators);
}
/**
* Gets the duration of time (seconds) for which the private key can be used after the user
* successfully authenticates to one of the associated user authenticators.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @return duration in seconds or {@code null} if not restricted. {@code 0} means authentication
* is required for every use of the key.
*
* @hide
*/
public Integer getUserAuthenticationValidityDurationSeconds() {
return mUserAuthenticationValidityDurationSeconds;
}
/**
* Builder class for {@link KeyPairGeneratorSpec} objects.
* <p>
* This will build a parameter spec for use with the <a href="{@docRoot}
* training/articles/keystore.html">Android KeyStore facility</a>.
* <p>
* The required fields must be filled in with the builder.
* <p>
* Example:
*
* <pre class="prettyprint">
* Calendar start = new Calendar();
* Calendar end = new Calendar();
* end.add(1, Calendar.YEAR);
*
* KeyPairGeneratorSpec spec =
* new KeyPairGeneratorSpec.Builder(mContext).setAlias(&quot;myKey&quot;)
* .setSubject(new X500Principal(&quot;CN=myKey&quot;)).setSerial(BigInteger.valueOf(1337))
* .setStartDate(start.getTime()).setEndDate(end.getTime()).build();
* </pre>
*/
public final static class Builder {
private final Context mContext;
private String mKeystoreAlias;
private String mKeyType;
private int mKeySize = -1;
private AlgorithmParameterSpec mSpec;
private X500Principal mSubjectDN;
private BigInteger mSerialNumber;
private Date mStartDate;
private Date mEndDate;
private int mFlags;
private Date mKeyValidityStart;
private Date mKeyValidityForOriginationEnd;
private Date mKeyValidityForConsumptionEnd;
private @KeyStoreKeyConstraints.PurposeEnum Integer mPurposes;
private @KeyStoreKeyConstraints.DigestEnum Integer mDigest;
private @KeyStoreKeyConstraints.PaddingEnum Integer mPadding;
private @KeyStoreKeyConstraints.BlockModeEnum Integer mBlockMode;
private Integer mMinSecondsBetweenOperations;
private Integer mMaxUsesPerBoot;
private Set<Integer> mUserAuthenticators;
private Integer mUserAuthenticationValidityDurationSeconds;
/**
* 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");
}
mContext = context;
}
/**
* Sets the alias to be used to retrieve the key later from a
* {@link java.security.KeyStore} instance using the
* {@code AndroidKeyStore} provider.
*/
public Builder setAlias(String alias) {
if (alias == null) {
throw new NullPointerException("alias == null");
}
mKeystoreAlias = alias;
return this;
}
/**
* Sets the key type (e.g., EC, RSA) of the keypair to be created.
*/
public Builder setKeyType(String keyType) throws NoSuchAlgorithmException {
if (keyType == null) {
throw new NullPointerException("keyType == null");
} else {
if (KeyStore.getKeyTypeForAlgorithm(keyType) == -1) {
throw new NoSuchAlgorithmException("Unsupported key type: " + keyType);
}
}
mKeyType = keyType;
return this;
}
/**
* Sets the key size for the keypair to be created. For instance, for a
* key type of RSA this will set the modulus size and for a key type of
* EC it will select a curve with a matching field size.
*/
public Builder setKeySize(int keySize) {
if (keySize < 0) {
throw new IllegalArgumentException("keySize < 0");
}
mKeySize = keySize;
return this;
}
/**
* Sets the algorithm-specific key generation parameters. For example, for RSA keys
* this may be an instance of {@link java.security.spec.RSAKeyGenParameterSpec}.
*/
public Builder setAlgorithmParameterSpec(AlgorithmParameterSpec spec) {
if (spec == null) {
throw new NullPointerException("spec == null");
}
mSpec = spec;
return this;
}
/**
* Sets the subject used for the self-signed certificate of the
* generated key pair.
*/
public Builder setSubject(X500Principal subject) {
if (subject == null) {
throw new NullPointerException("subject == null");
}
mSubjectDN = subject;
return this;
}
/**
* Sets the serial number used for the self-signed certificate of the
* generated key pair.
*/
public Builder setSerialNumber(BigInteger serialNumber) {
if (serialNumber == null) {
throw new NullPointerException("serialNumber == null");
}
mSerialNumber = serialNumber;
return this;
}
/**
* Sets the start of the validity period for the self-signed certificate
* of the generated key pair.
*/
public Builder setStartDate(Date startDate) {
if (startDate == null) {
throw new NullPointerException("startDate == null");
}
mStartDate = startDate;
return this;
}
/**
* Sets the end of the validity period for the self-signed certificate
* of the generated key pair.
*/
public Builder setEndDate(Date endDate) {
if (endDate == null) {
throw new NullPointerException("endDate == null");
}
mEndDate = endDate;
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;
}
/**
* Sets the time instant before which the key is not yet valid.
*
* <b>By default, the key is valid at any instant.
*
* @see #setKeyValidityEnd(Date)
*
* @hide
*/
public Builder setKeyValidityStart(Date startDate) {
mKeyValidityStart = startDate;
return this;
}
/**
* Sets the time instant after which the key is no longer valid.
*
* <b>By default, the key is valid at any instant.
*
* @see #setKeyValidityStart(Date)
* @see #setKeyValidityForConsumptionEnd(Date)
* @see #setKeyValidityForOriginationEnd(Date)
*
* @hide
*/
public Builder setKeyValidityEnd(Date endDate) {
setKeyValidityForOriginationEnd(endDate);
setKeyValidityForConsumptionEnd(endDate);
return this;
}
/**
* Sets the time instant after which the key is no longer valid for encryption and signing.
*
* <b>By default, the key is valid at any instant.
*
* @see #setKeyValidityForConsumptionEnd(Date)
*
* @hide
*/
public Builder setKeyValidityForOriginationEnd(Date endDate) {
mKeyValidityForOriginationEnd = endDate;
return this;
}
/**
* Sets the time instant after which the key is no longer valid for decryption and
* verification.
*
* <b>By default, the key is valid at any instant.
*
* @see #setKeyValidityForOriginationEnd(Date)
*
* @hide
*/
public Builder setKeyValidityForConsumptionEnd(Date endDate) {
mKeyValidityForConsumptionEnd = endDate;
return this;
}
/**
* Restricts the purposes for which the key can be used to the provided set of purposes.
*
* <p>By default, the key can be used for encryption, decryption, signing, and verification.
*
* @hide
*/
public Builder setPurposes(@KeyStoreKeyConstraints.PurposeEnum int purposes) {
mPurposes = purposes;
return this;
}
/**
* Restricts the key to being used only with the provided digest. Attempts to use the key
* with any other digests be rejected.
*
* <p>This restriction must be specified for keys which are used for signing/verification.
*
* @hide
*/
public Builder setDigest(@KeyStoreKeyConstraints.DigestEnum int digest) {
mDigest = digest;
return this;
}
/**
* Restricts the key to being used only with the provided padding scheme. Attempts to use
* the key with any other padding will be rejected.
*
* <p>This restriction must be specified for keys which are used for encryption/decryption.
*
* @hide
*/
public Builder setPadding(@KeyStoreKeyConstraints.PaddingEnum int padding) {
mPadding = padding;
return this;
}
/**
* Restricts the key to being used only with the provided block mode when encrypting or
* decrypting. Attempts to use the key with any other block modes will be rejected.
*
* <p>This restriction must be specified for keys which are used for encryption/decryption.
*
* @hide
*/
public Builder setBlockMode(@KeyStoreKeyConstraints.BlockModeEnum int blockMode) {
mBlockMode = blockMode;
return this;
}
/**
* Sets the minimum number of seconds that must expire since the most recent use of the key
* before it can be used again.
*
* <p>By default, there is no restriction on how frequently a key can be used.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @hide
*/
public Builder setMinSecondsBetweenOperations(int seconds) {
mMinSecondsBetweenOperations = seconds;
return this;
}
/**
* Sets the maximum number of times a key can be used without rebooting the device.
*
* <p>By default, the key can be used for an unlimited number of times.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @hide
*/
public Builder setMaxUsesPerBoot(int count) {
mMaxUsesPerBoot = count;
return this;
}
/**
* Sets the user authenticators which protect access to this key. The key can only be used
* iff the user has authenticated to at least one of these user authenticators.
*
* <p>By default, the key can be used without user authentication.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @param userAuthenticators user authenticators or empty list if this key can be accessed
* without user authentication.
*
* @see #setUserAuthenticationValidityDurationSeconds(int)
*
* @hide
*/
public Builder setUserAuthenticators(Set<Integer> userAuthenticators) {
mUserAuthenticators =
(userAuthenticators != null) ? new HashSet<Integer>(userAuthenticators) : null;
return this;
}
/**
* Sets the duration of time (seconds) for which this key can be used after the user
* successfully authenticates to one of the associated user authenticators.
*
* <p>By default, the user needs to authenticate for every use of the key.
*
* <p>This restriction applies only to private key operations. Public key operations are not
* restricted.
*
* @param seconds duration in seconds or {@code 0} if the user needs to authenticate for
* every use of the key.
*
* @see #setUserAuthenticators(Set)
*
* @hide
*/
public Builder setUserAuthenticationValidityDurationSeconds(int seconds) {
mUserAuthenticationValidityDurationSeconds = seconds;
return this;
}
/**
* Builds the instance of the {@code KeyPairGeneratorSpec}.
*
* @throws IllegalArgumentException if a required field is missing
* @return built instance of {@code KeyPairGeneratorSpec}
*/
public KeyPairGeneratorSpec build() {
return new KeyPairGeneratorSpec(mContext,
mKeystoreAlias,
mKeyType,
mKeySize,
mSpec,
mSubjectDN,
mSerialNumber,
mStartDate,
mEndDate,
mFlags,
mKeyValidityStart,
mKeyValidityForOriginationEnd,
mKeyValidityForConsumptionEnd,
mPurposes,
mDigest,
mPadding,
mBlockMode,
mMinSecondsBetweenOperations,
mMaxUsesPerBoot,
mUserAuthenticators,
mUserAuthenticationValidityDurationSeconds);
}
}
}