/*
 * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.security;

import java.io.*;
import java.util.*;

import java.security.KeyStore.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;

import javax.crypto.SecretKey;

import javax.security.auth.callback.*;

/**
 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
 * for the {@code KeyStore} class.
 * All the abstract methods in this class must be implemented by each
 * cryptographic service provider who wishes to supply the implementation
 * of a keystore for a particular keystore type.
 *
 * @author Jan Luehe
 *
 *
 * @see KeyStore
 *
 * @since 1.2
 */

public abstract class KeyStoreSpi {

 /**
 * Returns the key associated with the given alias, using the given
 * password to recover it. The key must have been associated with
 * the alias by a call to {@code setKeyEntry},
 * or by a call to {@code setEntry} with a
 * {@code PrivateKeyEntry} or {@code SecretKeyEntry}.
 *
 * @param alias the alias name
 * @param password the password for recovering the key
 *
 * @return the requested key, or null if the given alias does not exist
 * or does not identify a key-related entry.
 *
 * @exception NoSuchAlgorithmException if the algorithm for recovering the
 * key cannot be found
 * @exception UnrecoverableKeyException if the key cannot be recovered
 * (e.g., the given password is wrong).
 */
 public abstract Key engineGetKey(String alias, char[] password)
 throws NoSuchAlgorithmException, UnrecoverableKeyException;

 /**
 * Returns the certificate chain associated with the given alias.
 * The certificate chain must have been associated with the alias
 * by a call to {@code setKeyEntry},
 * or by a call to {@code setEntry} with a
 * {@code PrivateKeyEntry}.
 *
 * @param alias the alias name
 *
 * @return the certificate chain (ordered with the user's certificate first
 * and the root certificate authority last), or null if the given alias
 * does not exist or does not contain a certificate chain
 */
 public abstract Certificate[] engineGetCertificateChain(String alias);

 /**
 * Returns the certificate associated with the given alias.
 *
 * <p> If the given alias name identifies an entry
 * created by a call to {@code setCertificateEntry},
 * or created by a call to {@code setEntry} with a
 * {@code TrustedCertificateEntry},
 * then the trusted certificate contained in that entry is returned.
 *
 * <p> If the given alias name identifies an entry
 * created by a call to {@code setKeyEntry},
 * or created by a call to {@code setEntry} with a
 * {@code PrivateKeyEntry},
 * then the first element of the certificate chain in that entry
 * (if a chain exists) is returned.
 *
 * @param alias the alias name
 *
 * @return the certificate, or null if the given alias does not exist or
 * does not contain a certificate.
 */
 public abstract Certificate engineGetCertificate(String alias);

 /**
 * Returns the creation date of the entry identified by the given alias.
 *
 * @param alias the alias name
 *
 * @return the creation date of this entry, or null if the given alias does
 * not exist
 */
 public abstract Date engineGetCreationDate(String alias);

 /**
 * Assigns the given key to the given alias, protecting it with the given
 * password.
 *
 * <p>If the given key is of type {@code java.security.PrivateKey},
 * it must be accompanied by a certificate chain certifying the
 * corresponding public key.
 *
 * <p>If the given alias already exists, the keystore information
 * associated with it is overridden by the given key (and possibly
 * certificate chain).
 *
 * @param alias the alias name
 * @param key the key to be associated with the alias
 * @param password the password to protect the key
 * @param chain the certificate chain for the corresponding public
 * key (only required if the given key is of type
 * {@code java.security.PrivateKey}).
 *
 * @exception KeyStoreException if the given key cannot be protected, or
 * this operation fails for some other reason
 */
 public abstract void engineSetKeyEntry(String alias, Key key,
 char[] password,
 Certificate[] chain)
 throws KeyStoreException;

 /**
 * Assigns the given key (that has already been protected) to the given
 * alias.
 *
 * <p>If the protected key is of type
 * {@code java.security.PrivateKey},
 * it must be accompanied by a certificate chain certifying the
 * corresponding public key.
 *
 * <p>If the given alias already exists, the keystore information
 * associated with it is overridden by the given key (and possibly
 * certificate chain).
 *
 * @param alias the alias name
 * @param key the key (in protected format) to be associated with the alias
 * @param chain the certificate chain for the corresponding public
 * key (only useful if the protected key is of type
 * {@code java.security.PrivateKey}).
 *
 * @exception KeyStoreException if this operation fails.
 */
 public abstract void engineSetKeyEntry(String alias, byte[] key,
 Certificate[] chain)
 throws KeyStoreException;

 /**
 * Assigns the given certificate to the given alias.
 *
 * <p> If the given alias identifies an existing entry
 * created by a call to {@code setCertificateEntry},
 * or created by a call to {@code setEntry} with a
 * {@code TrustedCertificateEntry},
 * the trusted certificate in the existing entry
 * is overridden by the given certificate.
 *
 * @param alias the alias name
 * @param cert the certificate
 *
 * @exception KeyStoreException if the given alias already exists and does
 * not identify an entry containing a trusted certificate,
 * or this operation fails for some other reason.
 */
 public abstract void engineSetCertificateEntry(String alias,
 Certificate cert)
 throws KeyStoreException;

 /**
 * Deletes the entry identified by the given alias from this keystore.
 *
 * @param alias the alias name
 *
 * @exception KeyStoreException if the entry cannot be removed.
 */
 public abstract void engineDeleteEntry(String alias)
 throws KeyStoreException;

 /**
 * Lists all the alias names of this keystore.
 *
 * @return enumeration of the alias names
 */
 public abstract Enumeration<String> engineAliases();

 /**
 * Checks if the given alias exists in this keystore.
 *
 * @param alias the alias name
 *
 * @return true if the alias exists, false otherwise
 */
 public abstract boolean engineContainsAlias(String alias);

 /**
 * Retrieves the number of entries in this keystore.
 *
 * @return the number of entries in this keystore
 */
 public abstract int engineSize();

 /**
 * Returns true if the entry identified by the given alias
 * was created by a call to {@code setKeyEntry},
 * or created by a call to {@code setEntry} with a
 * {@code PrivateKeyEntry} or a {@code SecretKeyEntry}.
 *
 * @param alias the alias for the keystore entry to be checked
 *
 * @return true if the entry identified by the given alias is a
 * key-related, false otherwise.
 */
 public abstract boolean engineIsKeyEntry(String alias);

 /**
 * Returns true if the entry identified by the given alias
 * was created by a call to {@code setCertificateEntry},
 * or created by a call to {@code setEntry} with a
 * {@code TrustedCertificateEntry}.
 *
 * @param alias the alias for the keystore entry to be checked
 *
 * @return true if the entry identified by the given alias contains a
 * trusted certificate, false otherwise.
 */
 public abstract boolean engineIsCertificateEntry(String alias);

 /**
 * Returns the (alias) name of the first keystore entry whose certificate
 * matches the given certificate.
 *
 * <p>This method attempts to match the given certificate with each
 * keystore entry. If the entry being considered was
 * created by a call to {@code setCertificateEntry},
 * or created by a call to {@code setEntry} with a
 * {@code TrustedCertificateEntry},
 * then the given certificate is compared to that entry's certificate.
 *
 * <p> If the entry being considered was
 * created by a call to {@code setKeyEntry},
 * or created by a call to {@code setEntry} with a
 * {@code PrivateKeyEntry},
 * then the given certificate is compared to the first
 * element of that entry's certificate chain.
 *
 * @param cert the certificate to match with.
 *
 * @return the alias name of the first entry with matching certificate,
 * or null if no such entry exists in this keystore.
 */
 public abstract String engineGetCertificateAlias(Certificate cert);

 /**
 * Stores this keystore to the given output stream, and protects its
 * integrity with the given password.
 *
 * @param stream the output stream to which this keystore is written.
 * @param password the password to generate the keystore integrity check
 *
 * @exception IOException if there was an I/O problem with data
 * @exception NoSuchAlgorithmException if the appropriate data integrity
 * algorithm could not be found
 * @exception CertificateException if any of the certificates included in
 * the keystore data could not be stored
 */
 public abstract void engineStore(OutputStream stream, char[] password)
 throws IOException, NoSuchAlgorithmException, CertificateException;

 /**
 * Stores this keystore using the given
 * {@code KeyStore.LoadStoreParmeter}.
 *
 * @param param the {@code KeyStore.LoadStoreParmeter}
 * that specifies how to store the keystore,
 * which may be {@code null}
 *
 * @exception IllegalArgumentException if the given
 * {@code KeyStore.LoadStoreParmeter}
 * input is not recognized
 * @exception IOException if there was an I/O problem with data
 * @exception NoSuchAlgorithmException if the appropriate data integrity
 * algorithm could not be found
 * @exception CertificateException if any of the certificates included in
 * the keystore data could not be stored
 *
 * @since 1.5
 */
 public void engineStore(KeyStore.LoadStoreParameter param)
 throws IOException, NoSuchAlgorithmException,
 CertificateException {
 throw new UnsupportedOperationException();
 }

 /**
 * Loads the keystore from the given input stream.
 *
 * <p>A password may be given to unlock the keystore
 * (e.g. the keystore resides on a hardware token device),
 * or to check the integrity of the keystore data.
 * If a password is not given for integrity checking,
 * then integrity checking is not performed.
 *
 * @param stream the input stream from which the keystore is loaded,
 * or {@code null}
 * @param password the password used to check the integrity of
 * the keystore, the password used to unlock the keystore,
 * or {@code null}
 *
 * @exception IOException if there is an I/O or format problem with the
 * keystore data, if a password is required but not given,
 * or if the given password was incorrect. If the error is due to a
 * wrong password, the {@link Throwable#getCause cause} of the
 * {@code IOException} should be an
 * {@code UnrecoverableKeyException}
 * @exception NoSuchAlgorithmException if the algorithm used to check
 * the integrity of the keystore cannot be found
 * @exception CertificateException if any of the certificates in the
 * keystore could not be loaded
 */
 public abstract void engineLoad(InputStream stream, char[] password)
 throws IOException, NoSuchAlgorithmException, CertificateException;

 /**
 * Loads the keystore using the given
 * {@code KeyStore.LoadStoreParameter}.
 *
 * <p> Note that if this KeyStore has already been loaded, it is
 * reinitialized and loaded again from the given parameter.
 *
 * @param param the {@code KeyStore.LoadStoreParameter}
 * that specifies how to load the keystore,
 * which may be {@code null}
 *
 * @exception IllegalArgumentException if the given
 * {@code KeyStore.LoadStoreParameter}
 * input is not recognized
 * @exception IOException if there is an I/O or format problem with the
 * keystore data. If the error is due to an incorrect
 * {@code ProtectionParameter} (e.g. wrong password)
 * the {@link Throwable#getCause cause} of the
 * {@code IOException} should be an
 * {@code UnrecoverableKeyException}
 * @exception NoSuchAlgorithmException if the algorithm used to check
 * the integrity of the keystore cannot be found
 * @exception CertificateException if any of the certificates in the
 * keystore could not be loaded
 *
 * @since 1.5
 */
 public void engineLoad(KeyStore.LoadStoreParameter param)
 throws IOException, NoSuchAlgorithmException,
 CertificateException {

 if (param == null) {
 engineLoad((InputStream)null, (char[])null);
 return;
 }

 if (param instanceof KeyStore.SimpleLoadStoreParameter) {
 ProtectionParameter protection = param.getProtectionParameter();
 char[] password;
 if (protection instanceof PasswordProtection) {
 password = ((PasswordProtection)protection).getPassword();
 } else if (protection instanceof CallbackHandlerProtection) {
 CallbackHandler handler =
 ((CallbackHandlerProtection)protection).getCallbackHandler();
 PasswordCallback callback =
 new PasswordCallback("Password: ", false);
 try {
 handler.handle(new Callback[] {callback});
 } catch (UnsupportedCallbackException e) {
 throw new NoSuchAlgorithmException
 ("Could not obtain password", e);
 }
 password = callback.getPassword();
 callback.clearPassword();
 if (password == null) {
 throw new NoSuchAlgorithmException
 ("No password provided");
 }
 } else {
 throw new NoSuchAlgorithmException("ProtectionParameter must"
 + " be PasswordProtection or CallbackHandlerProtection");
 }
 engineLoad(null, password);
 return;
 }

 throw new UnsupportedOperationException();
 }

 /**
 * Gets a {@code KeyStore.Entry} for the specified alias
 * with the specified protection parameter.
 *
 * @param alias get the {@code KeyStore.Entry} for this alias
 * @param protParam the {@code ProtectionParameter}
 * used to protect the {@code Entry},
 * which may be {@code null}
 *
 * @return the {@code KeyStore.Entry} for the specified alias,
 * or {@code null} if there is no such entry
 *
 * @exception KeyStoreException if the operation failed
 * @exception NoSuchAlgorithmException if the algorithm for recovering the
 * entry cannot be found
 * @exception UnrecoverableEntryException if the specified
 * {@code protParam} were insufficient or invalid
 * @exception UnrecoverableKeyException if the entry is a
 * {@code PrivateKeyEntry} or {@code SecretKeyEntry}
 * and the specified {@code protParam} does not contain
 * the information needed to recover the key (e.g. wrong password)
 *
 * @since 1.5
 */
 public KeyStore.Entry engineGetEntry(String alias,
 KeyStore.ProtectionParameter protParam)
 throws KeyStoreException, NoSuchAlgorithmException,
 UnrecoverableEntryException {

 if (!engineContainsAlias(alias)) {
 return null;
 }

 if (protParam == null) {
 if (engineIsCertificateEntry(alias)) {
 return new KeyStore.TrustedCertificateEntry
 (engineGetCertificate(alias));
 } else {
 throw new UnrecoverableKeyException
 ("requested entry requires a password");
 }
 }

 if (protParam instanceof KeyStore.PasswordProtection) {
 if (engineIsCertificateEntry(alias)) {
 throw new UnsupportedOperationException
 ("trusted certificate entries are not password-protected");
 } else if (engineIsKeyEntry(alias)) {
 KeyStore.PasswordProtection pp =
 (KeyStore.PasswordProtection)protParam;
 char[] password = pp.getPassword();

 Key key = engineGetKey(alias, password);
 if (key instanceof PrivateKey) {
 Certificate[] chain = engineGetCertificateChain(alias);
 return new KeyStore.PrivateKeyEntry((PrivateKey)key, chain);
 } else if (key instanceof SecretKey) {
 return new KeyStore.SecretKeyEntry((SecretKey)key);
 }
 }
 }

 throw new UnsupportedOperationException();
 }

 /**
 * Saves a {@code KeyStore.Entry} under the specified alias.
 * The specified protection parameter is used to protect the
 * {@code Entry}.
 *
 * <p> If an entry already exists for the specified alias,
 * it is overridden.
 *
 * @param alias save the {@code KeyStore.Entry} under this alias
 * @param entry the {@code Entry} to save
 * @param protParam the {@code ProtectionParameter}
 * used to protect the {@code Entry},
 * which may be {@code null}
 *
 * @exception KeyStoreException if this operation fails
 *
 * @since 1.5
 */
 public void engineSetEntry(String alias, KeyStore.Entry entry,
 KeyStore.ProtectionParameter protParam)
 throws KeyStoreException {

 // get password
 if (protParam != null &&
 !(protParam instanceof KeyStore.PasswordProtection)) {
 throw new KeyStoreException("unsupported protection parameter");
 }
 KeyStore.PasswordProtection pProtect = null;
 if (protParam != null) {
 pProtect = (KeyStore.PasswordProtection)protParam;
 }

 // set entry
 if (entry instanceof KeyStore.TrustedCertificateEntry) {
 if (protParam != null && pProtect.getPassword() != null) {
 // pre-1.5 style setCertificateEntry did not allow password
 throw new KeyStoreException
 ("trusted certificate entries are not password-protected");
 } else {
 KeyStore.TrustedCertificateEntry tce =
 (KeyStore.TrustedCertificateEntry)entry;
 engineSetCertificateEntry(alias, tce.getTrustedCertificate());
 return;
 }
 } else if (entry instanceof KeyStore.PrivateKeyEntry) {
 if (pProtect == null || pProtect.getPassword() == null) {
 // pre-1.5 style setKeyEntry required password
 throw new KeyStoreException
 ("non-null password required to create PrivateKeyEntry");
 } else {
 engineSetKeyEntry
 (alias,
 ((KeyStore.PrivateKeyEntry)entry).getPrivateKey(),
 pProtect.getPassword(),
 ((KeyStore.PrivateKeyEntry)entry).getCertificateChain());
 return;
 }
 } else if (entry instanceof KeyStore.SecretKeyEntry) {
 if (pProtect == null || pProtect.getPassword() == null) {
 // pre-1.5 style setKeyEntry required password
 throw new KeyStoreException
 ("non-null password required to create SecretKeyEntry");
 } else {
 engineSetKeyEntry
 (alias,
 ((KeyStore.SecretKeyEntry)entry).getSecretKey(),
 pProtect.getPassword(),
 (Certificate[])null);
 return;
 }
 }

 throw new KeyStoreException
 ("unsupported entry type: " + entry.getClass().getName());
 }

 /**
 * Determines if the keystore {@code Entry} for the specified
 * {@code alias} is an instance or subclass of the specified
 * {@code entryClass}.
 *
 * @param alias the alias name
 * @param entryClass the entry class
 *
 * @return true if the keystore {@code Entry} for the specified
 * {@code alias} is an instance or subclass of the
 * specified {@code entryClass}, false otherwise
 *
 * @since 1.5
 */
 public boolean
 engineEntryInstanceOf(String alias,
 Class<? extends KeyStore.Entry> entryClass)
 {
 if (entryClass == KeyStore.TrustedCertificateEntry.class) {
 return engineIsCertificateEntry(alias);
 }
 if (entryClass == KeyStore.PrivateKeyEntry.class) {
 return engineIsKeyEntry(alias) &&
 engineGetCertificate(alias) != null;
 }
 if (entryClass == KeyStore.SecretKeyEntry.class) {
 return engineIsKeyEntry(alias) &&
 engineGetCertificate(alias) == null;
 }
 return false;
 }
}