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	/*
	* Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package com.sun.crypto.provider;

	import java.io.IOException;
	import java.security.Key;
	import java.security.PrivateKey;
	import java.security.Provider;
	import java.security.KeyFactory;
	import java.security.MessageDigest;
	import java.security.GeneralSecurityException;
	import java.security.NoSuchAlgorithmException;
	import java.security.UnrecoverableKeyException;
	import java.security.AlgorithmParameters;
	import java.security.spec.InvalidParameterSpecException;
	import java.security.spec.PKCS8EncodedKeySpec;

	import javax.crypto.Cipher;
	import javax.crypto.CipherSpi;
	import javax.crypto.SecretKey;
	import javax.crypto.SealedObject;
	import javax.crypto.spec.*;
	import sun.security.x509.AlgorithmId;
	import sun.security.util.ObjectIdentifier;

	/**
	* This class implements a protection mechanism for private keys. In JCE, we
	* use a stronger protection mechanism than in the JDK, because we can use
	* the <code>Cipher</code> class.
	* Private keys are protected using the JCE mechanism, and are recovered using
	* either the JDK or JCE mechanism, depending on how the key has been
	* protected. This allows us to parse Sun's keystore implementation that ships
	* with JDK 1.2.
	*
	* @author Jan Luehe
	*
	*
	* @see JceKeyStore
	*/

	final class KeyProtector {

	// defined by SunSoft (SKI project)
	private static final String PBE_WITH_MD5_AND_DES3_CBC_OID
	= "1.3.6.1.4.1.42.2.19.1";

	// JavaSoft proprietary key-protection algorithm (used to protect private
	// keys in the keystore implementation that comes with JDK 1.2)
	private static final String KEY_PROTECTOR_OID = "1.3.6.1.4.1.42.2.17.1.1";

	private static final int MAX_ITERATION_COUNT = 5000000;
	private static final int ITERATION_COUNT = 200000;
	private static final int SALT_LEN = 20; // the salt length
	private static final int DIGEST_LEN = 20;

	// the password used for protecting/recovering keys passed through this
	// key protector
	private char[] password;

	KeyProtector(char[] password) {
	if (password == null) {
	throw new IllegalArgumentException("password can't be null");
	}
	this.password = password;
	}

	/**
	* Protects the given cleartext private key, using the password provided at
	* construction time.
	*/
	byte[] protect(PrivateKey key)
	throws Exception
	{
	// create a random salt (8 bytes)
	byte[] salt = new byte[8];
	SunJCE.getRandom().nextBytes(salt);

	// create PBE parameters from salt and iteration count
	PBEParameterSpec pbeSpec = new PBEParameterSpec(salt, ITERATION_COUNT);

	// create PBE key from password
	PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
	SecretKey sKey = new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
	pbeKeySpec.clearPassword();

	// encrypt private key
	PBEWithMD5AndTripleDESCipher cipher;
	cipher = new PBEWithMD5AndTripleDESCipher();
	cipher.engineInit(Cipher.ENCRYPT_MODE, sKey, pbeSpec, null);
	byte[] plain = key.getEncoded();
	byte[] encrKey = cipher.engineDoFinal(plain, 0, plain.length);

	// wrap encrypted private key in EncryptedPrivateKeyInfo
	// (as defined in PKCS#8)
	AlgorithmParameters pbeParams =
	AlgorithmParameters.getInstance("PBE", SunJCE.getInstance());
	pbeParams.init(pbeSpec);

	AlgorithmId encrAlg = new AlgorithmId
	(new ObjectIdentifier(PBE_WITH_MD5_AND_DES3_CBC_OID), pbeParams);
	return new EncryptedPrivateKeyInfo(encrAlg,encrKey).getEncoded();
	}

	/*
	* Recovers the cleartext version of the given key (in protected format),
	* using the password provided at construction time.
	*/
	Key recover(EncryptedPrivateKeyInfo encrInfo)
	throws UnrecoverableKeyException, NoSuchAlgorithmException
	{
	byte[] plain;

	try {
	String encrAlg = encrInfo.getAlgorithm().getOID().toString();
	if (!encrAlg.equals(PBE_WITH_MD5_AND_DES3_CBC_OID)
	&& !encrAlg.equals(KEY_PROTECTOR_OID)) {
	throw new UnrecoverableKeyException("Unsupported encryption "
	+ "algorithm");
	}

	if (encrAlg.equals(KEY_PROTECTOR_OID)) {
	// JDK 1.2 style recovery
	plain = recover(encrInfo.getEncryptedData());
	} else {
	byte[] encodedParams =
	encrInfo.getAlgorithm().getEncodedParams();

	// parse the PBE parameters into the corresponding spec
	AlgorithmParameters pbeParams =
	AlgorithmParameters.getInstance("PBE");
	pbeParams.init(encodedParams);
	PBEParameterSpec pbeSpec =
	pbeParams.getParameterSpec(PBEParameterSpec.class);
	if (pbeSpec.getIterationCount() > MAX_ITERATION_COUNT) {
	throw new IOException("PBE iteration count too large");
	}

	// create PBE key from password
	PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
	SecretKey sKey =
	new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
	pbeKeySpec.clearPassword();

	// decrypt private key
	PBEWithMD5AndTripleDESCipher cipher;
	cipher = new PBEWithMD5AndTripleDESCipher();
	cipher.engineInit(Cipher.DECRYPT_MODE, sKey, pbeSpec, null);
	plain=cipher.engineDoFinal(encrInfo.getEncryptedData(), 0,
	encrInfo.getEncryptedData().length);
	}

	// determine the private-key algorithm, and parse private key
	// using the appropriate key factory
	String oidName = new AlgorithmId
	(new PrivateKeyInfo(plain).getAlgorithm().getOID()).getName();
	KeyFactory kFac = KeyFactory.getInstance(oidName);
	return kFac.generatePrivate(new PKCS8EncodedKeySpec(plain));

	} catch (NoSuchAlgorithmException ex) {
	// Note: this catch needed to be here because of the
	// later catch of GeneralSecurityException
	throw ex;
	} catch (IOException ioe) {
	throw new UnrecoverableKeyException(ioe.getMessage());
	} catch (GeneralSecurityException gse) {
	throw new UnrecoverableKeyException(gse.getMessage());
	}
	}

	/*
	* Recovers the cleartext version of the given key (in protected format),
	* using the password provided at construction time. This method implements
	* the recovery algorithm used by Sun's keystore implementation in
	* JDK 1.2.
	*/
	private byte[] recover(byte[] protectedKey)
	throws UnrecoverableKeyException, NoSuchAlgorithmException
	{
	int i, j;
	byte[] digest;
	int numRounds;
	int xorOffset; // offset in xorKey where next digest will be stored
	int encrKeyLen; // the length of the encrpyted key

	MessageDigest md = MessageDigest.getInstance("SHA");

	// Get the salt associated with this key (the first SALT_LEN bytes of
	// <code>protectedKey</code>)
	byte[] salt = new byte[SALT_LEN];
	System.arraycopy(protectedKey, 0, salt, 0, SALT_LEN);

	// Determine the number of digest rounds
	encrKeyLen = protectedKey.length - SALT_LEN - DIGEST_LEN;
	numRounds = encrKeyLen / DIGEST_LEN;
	if ((encrKeyLen % DIGEST_LEN) != 0)
	numRounds++;

	// Get the encrypted key portion and store it in "encrKey"
	byte[] encrKey = new byte[encrKeyLen];
	System.arraycopy(protectedKey, SALT_LEN, encrKey, 0, encrKeyLen);

	// Set up the byte array which will be XORed with "encrKey"
	byte[] xorKey = new byte[encrKey.length];

	// Convert password to byte array, so that it can be digested
	byte[] passwdBytes = new byte[password.length * 2];
	for (i=0, j=0; i<password.length; i++) {
	passwdBytes[j++] = (byte)(password[i] >> 8);
	passwdBytes[j++] = (byte)password[i];
	}

	// Compute the digests, and store them in "xorKey"
	for (i = 0, xorOffset = 0, digest = salt;
	i < numRounds;
	i++, xorOffset += DIGEST_LEN) {
	md.update(passwdBytes);
	md.update(digest);
	digest = md.digest();
	md.reset();
	// Copy the digest into "xorKey"
	if (i < numRounds - 1) {
	System.arraycopy(digest, 0, xorKey, xorOffset,
	digest.length);
	} else {
	System.arraycopy(digest, 0, xorKey, xorOffset,
	xorKey.length - xorOffset);
	}
	}

	// XOR "encrKey" with "xorKey", and store the result in "plainKey"
	byte[] plainKey = new byte[encrKey.length];
	for (i = 0; i < plainKey.length; i++) {
	plainKey[i] = (byte)(encrKey[i] ^ xorKey[i]);
	}

	// Check the integrity of the recovered key by concatenating it with
	// the password, digesting the concatenation, and comparing the
	// result of the digest operation with the digest provided at the end
	// of <code>protectedKey</code>. If the two digest values are
	// different, throw an exception.
	md.update(passwdBytes);
	java.util.Arrays.fill(passwdBytes, (byte)0x00);
	passwdBytes = null;
	md.update(plainKey);
	digest = md.digest();
	md.reset();
	for (i = 0; i < digest.length; i++) {
	if (digest[i] != protectedKey[SALT_LEN + encrKeyLen + i]) {
	throw new UnrecoverableKeyException("Cannot recover key");
	}
	}
	return plainKey;
	}

	/**
	* Seals the given cleartext key, using the password provided at
	* construction time
	*/
	SealedObject seal(Key key)
	throws Exception
	{
	// create a random salt (8 bytes)
	byte[] salt = new byte[8];
	SunJCE.getRandom().nextBytes(salt);

	// create PBE parameters from salt and iteration count
	PBEParameterSpec pbeSpec = new PBEParameterSpec(salt, ITERATION_COUNT);

	// create PBE key from password
	PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
	SecretKey sKey = new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
	pbeKeySpec.clearPassword();

	// seal key
	Cipher cipher;

	PBEWithMD5AndTripleDESCipher cipherSpi;
	cipherSpi = new PBEWithMD5AndTripleDESCipher();
	cipher = new CipherForKeyProtector(cipherSpi, SunJCE.getInstance(),
	"PBEWithMD5AndTripleDES");
	cipher.init(Cipher.ENCRYPT_MODE, sKey, pbeSpec);
	return new SealedObjectForKeyProtector(key, cipher);
	}

	/**
	* Unseals the sealed key.
	*/
	Key unseal(SealedObject so)
	throws NoSuchAlgorithmException, UnrecoverableKeyException
	{
	try {
	// create PBE key from password
	PBEKeySpec pbeKeySpec = new PBEKeySpec(this.password);
	SecretKey skey = new PBEKey(pbeKeySpec, "PBEWithMD5AndTripleDES");
	pbeKeySpec.clearPassword();

	SealedObjectForKeyProtector soForKeyProtector = null;
	if (!(so instanceof SealedObjectForKeyProtector)) {
	soForKeyProtector = new SealedObjectForKeyProtector(so);
	} else {
	soForKeyProtector = (SealedObjectForKeyProtector)so;
	}
	AlgorithmParameters params = soForKeyProtector.getParameters();
	if (params == null) {
	throw new UnrecoverableKeyException("Cannot get " +
	"algorithm parameters");
	}
	PBEParameterSpec pbeSpec;
	try {
	pbeSpec = params.getParameterSpec(PBEParameterSpec.class);
	} catch (InvalidParameterSpecException ipse) {
	throw new IOException("Invalid PBE algorithm parameters");
	}
	if (pbeSpec.getIterationCount() > MAX_ITERATION_COUNT) {
	throw new IOException("PBE iteration count too large");
	}
	PBEWithMD5AndTripleDESCipher cipherSpi;
	cipherSpi = new PBEWithMD5AndTripleDESCipher();
	Cipher cipher = new CipherForKeyProtector(cipherSpi,
	SunJCE.getInstance(),
	"PBEWithMD5AndTripleDES");
	cipher.init(Cipher.DECRYPT_MODE, skey, params);
	return soForKeyProtector.getKey(cipher);
	} catch (NoSuchAlgorithmException ex) {
	// Note: this catch needed to be here because of the
	// later catch of GeneralSecurityException
	throw ex;
	} catch (IOException ioe) {
	throw new UnrecoverableKeyException(ioe.getMessage());
	} catch (ClassNotFoundException cnfe) {
	throw new UnrecoverableKeyException(cnfe.getMessage());
	} catch (GeneralSecurityException gse) {
	throw new UnrecoverableKeyException(gse.getMessage());
	}
	}
	}


	final class CipherForKeyProtector extends javax.crypto.Cipher {
	/**
	* Creates a Cipher object.
	*
	* @param cipherSpi the delegate
	* @param provider the provider
	* @param transformation the transformation
	*/
	protected CipherForKeyProtector(CipherSpi cipherSpi,
	Provider provider,
	String transformation) {
	super(cipherSpi, provider, transformation);
	}
	}

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