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	/*
	* Copyright (c) 2003, 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 sun.security.rsa;

	import java.math.BigInteger;

	import java.security.*;
	import java.security.interfaces.*;
	import java.security.spec.*;

	import sun.security.action.GetPropertyAction;
	import sun.security.x509.AlgorithmId;
	import static sun.security.rsa.RSAUtil.KeyType;

	/**
	* KeyFactory for RSA keys, e.g. "RSA", "RSASSA-PSS".
	* Keys must be instances of PublicKey or PrivateKey
	* and getAlgorithm() must return a value which matches the type which are
	* specified during construction time of the KeyFactory object.
	* For such keys, it supports conversion
	* between the following:
	*
	* For public keys:
	* . PublicKey with an X.509 encoding
	* . RSAPublicKey
	* . RSAPublicKeySpec
	* . X509EncodedKeySpec
	*
	* For private keys:
	* . PrivateKey with a PKCS#8 encoding
	* . RSAPrivateKey
	* . RSAPrivateCrtKey
	* . RSAPrivateKeySpec
	* . RSAPrivateCrtKeySpec
	* . PKCS8EncodedKeySpec
	* (of course, CRT variants only for CRT keys)
	*
	* Note: as always, RSA keys should be at least 512 bits long
	*
	* @since 1.5
	* @author Andreas Sterbenz
	*/
	public class RSAKeyFactory extends KeyFactorySpi {

	private static final Class<?> RSA_PUB_KEYSPEC_CLS = RSAPublicKeySpec.class;
	private static final Class<?> RSA_PRIV_KEYSPEC_CLS =
	RSAPrivateKeySpec.class;
	private static final Class<?> RSA_PRIVCRT_KEYSPEC_CLS =
	RSAPrivateCrtKeySpec.class;
	private static final Class<?> X509_KEYSPEC_CLS = X509EncodedKeySpec.class;
	private static final Class<?> PKCS8_KEYSPEC_CLS = PKCS8EncodedKeySpec.class;

	public static final int MIN_MODLEN = 512;
	public static final int MAX_MODLEN = 16384;

	private final KeyType type;

	/*
	* If the modulus length is above this value, restrict the size of
	* the exponent to something that can be reasonably computed. We
	* could simply hardcode the exp len to something like 64 bits, but
	* this approach allows flexibility in case impls would like to use
	* larger module and exponent values.
	*/
	public static final int MAX_MODLEN_RESTRICT_EXP = 3072;
	public static final int MAX_RESTRICTED_EXPLEN = 64;

	private static final boolean restrictExpLen =
	"true".equalsIgnoreCase(GetPropertyAction.privilegedGetProperty(
	"sun.security.rsa.restrictRSAExponent", "true"));

	static RSAKeyFactory getInstance(KeyType type) {
	return new RSAKeyFactory(type);
	}

	// Internal utility method for checking key algorithm
	private static void checkKeyAlgo(Key key, String expectedAlg)
	throws InvalidKeyException {
	String keyAlg = key.getAlgorithm();
	if (keyAlg == null \|\| !(keyAlg.equalsIgnoreCase(expectedAlg))) {
	throw new InvalidKeyException("Expected a " + expectedAlg
	+ " key, but got " + keyAlg);
	}
	}

	/**
	* Static method to convert Key into an instance of RSAPublicKeyImpl
	* or RSAPrivate(Crt)KeyImpl. If the key is not an RSA key or cannot be
	* used, throw an InvalidKeyException.
	*
	* Used by RSASignature and RSACipher.
	*/
	public static RSAKey toRSAKey(Key key) throws InvalidKeyException {
	if (key == null) {
	throw new InvalidKeyException("Key must not be null");
	}
	if ((key instanceof RSAPrivateKeyImpl) \|\|
	(key instanceof RSAPrivateCrtKeyImpl) \|\|
	(key instanceof RSAPublicKeyImpl)) {
	return (RSAKey)key;
	} else {
	try {
	KeyType type = KeyType.lookup(key.getAlgorithm());
	RSAKeyFactory kf = RSAKeyFactory.getInstance(type);
	return (RSAKey) kf.engineTranslateKey(key);
	} catch (ProviderException e) {
	throw new InvalidKeyException(e);
	}
	}
	}

	/*
	* Single test entry point for all of the mechanisms in the SunRsaSign
	* provider (RSA*KeyImpls). All of the tests are the same.
	*
	* For compatibility, we round up to the nearest byte here:
	* some Key impls might pass in a value within a byte of the
	* real value.
	*/
	static void checkRSAProviderKeyLengths(int modulusLen, BigInteger exponent)
	throws InvalidKeyException {
	checkKeyLengths(((modulusLen + 7) & ~7), exponent,
	RSAKeyFactory.MIN_MODLEN, Integer.MAX_VALUE);
	}

	/**
	* Check the length of an RSA key modulus/exponent to make sure it
	* is not too short or long. Some impls have their own min and
	* max key sizes that may or may not match with a system defined value.
	*
	* @param modulusLen the bit length of the RSA modulus.
	* @param exponent the RSA exponent
	* @param minModulusLen if {@literal > 0}, check to see if modulusLen is at
	* least this long, otherwise unused.
	* @param maxModulusLen caller will allow this max number of bits.
	* Allow the smaller of the system-defined maximum and this param.
	*
	* @throws InvalidKeyException if any of the values are unacceptable.
	*/
	public static void checkKeyLengths(int modulusLen, BigInteger exponent,
	int minModulusLen, int maxModulusLen) throws InvalidKeyException {

	if ((minModulusLen > 0) && (modulusLen < (minModulusLen))) {
	throw new InvalidKeyException( "RSA keys must be at least " +
	minModulusLen + " bits long");
	}

	// Even though our policy file may allow this, we don't want
	// either value (mod/exp) to be too big.

	int maxLen = Math.min(maxModulusLen, MAX_MODLEN);

	// If a RSAPrivateKey/RSAPublicKey, make sure the
	// modulus len isn't too big.
	if (modulusLen > maxLen) {
	throw new InvalidKeyException(
	"RSA keys must be no longer than " + maxLen + " bits");
	}

	// If a RSAPublicKey, make sure the exponent isn't too big.
	if (restrictExpLen && (exponent != null) &&
	(modulusLen > MAX_MODLEN_RESTRICT_EXP) &&
	(exponent.bitLength() > MAX_RESTRICTED_EXPLEN)) {
	throw new InvalidKeyException(
	"RSA exponents can be no longer than " +
	MAX_RESTRICTED_EXPLEN + " bits " +
	" if modulus is greater than " +
	MAX_MODLEN_RESTRICT_EXP + " bits");
	}
	}

	// disallowed as KeyType is required
	private RSAKeyFactory() {
	this.type = KeyType.RSA;
	}

	public RSAKeyFactory(KeyType type) {
	this.type = type;
	}

	/**
	* Translate an RSA key into a SunRsaSign RSA key. If conversion is
	* not possible, throw an InvalidKeyException.
	* See also JCA doc.
	*/
	protected Key engineTranslateKey(Key key) throws InvalidKeyException {
	if (key == null) {
	throw new InvalidKeyException("Key must not be null");
	}
	// ensure the key algorithm matches the current KeyFactory instance
	checkKeyAlgo(key, type.keyAlgo());

	// no translation needed if the key is already our own impl
	if ((key instanceof RSAPrivateKeyImpl) \|\|
	(key instanceof RSAPrivateCrtKeyImpl) \|\|
	(key instanceof RSAPublicKeyImpl)) {
	return key;
	}
	if (key instanceof PublicKey) {
	return translatePublicKey((PublicKey)key);
	} else if (key instanceof PrivateKey) {
	return translatePrivateKey((PrivateKey)key);
	} else {
	throw new InvalidKeyException("Neither a public nor a private key");
	}
	}

	// see JCA doc
	protected PublicKey engineGeneratePublic(KeySpec keySpec)
	throws InvalidKeySpecException {
	try {
	return generatePublic(keySpec);
	} catch (InvalidKeySpecException e) {
	throw e;
	} catch (GeneralSecurityException e) {
	throw new InvalidKeySpecException(e);
	}
	}

	// see JCA doc
	protected PrivateKey engineGeneratePrivate(KeySpec keySpec)
	throws InvalidKeySpecException {
	try {
	return generatePrivate(keySpec);
	} catch (InvalidKeySpecException e) {
	throw e;
	} catch (GeneralSecurityException e) {
	throw new InvalidKeySpecException(e);
	}
	}

	// internal implementation of translateKey() for public keys. See JCA doc
	private PublicKey translatePublicKey(PublicKey key)
	throws InvalidKeyException {
	if (key instanceof RSAPublicKey) {
	RSAPublicKey rsaKey = (RSAPublicKey)key;
	try {
	return new RSAPublicKeyImpl(
	RSAUtil.createAlgorithmId(type, rsaKey.getParams()),
	rsaKey.getModulus(),
	rsaKey.getPublicExponent());
	} catch (ProviderException e) {
	// catch providers that incorrectly implement RSAPublicKey
	throw new InvalidKeyException("Invalid key", e);
	}
	} else if ("X.509".equals(key.getFormat())) {
	RSAPublicKey translated = new RSAPublicKeyImpl(key.getEncoded());
	// ensure the key algorithm matches the current KeyFactory instance
	checkKeyAlgo(translated, type.keyAlgo());
	return translated;
	} else {
	throw new InvalidKeyException("Public keys must be instance "
	+ "of RSAPublicKey or have X.509 encoding");
	}
	}

	// internal implementation of translateKey() for private keys. See JCA doc
	private PrivateKey translatePrivateKey(PrivateKey key)
	throws InvalidKeyException {
	if (key instanceof RSAPrivateCrtKey) {
	RSAPrivateCrtKey rsaKey = (RSAPrivateCrtKey)key;
	try {
	return new RSAPrivateCrtKeyImpl(
	RSAUtil.createAlgorithmId(type, rsaKey.getParams()),
	rsaKey.getModulus(),
	rsaKey.getPublicExponent(),
	rsaKey.getPrivateExponent(),
	rsaKey.getPrimeP(),
	rsaKey.getPrimeQ(),
	rsaKey.getPrimeExponentP(),
	rsaKey.getPrimeExponentQ(),
	rsaKey.getCrtCoefficient()
	);
	} catch (ProviderException e) {
	// catch providers that incorrectly implement RSAPrivateCrtKey
	throw new InvalidKeyException("Invalid key", e);
	}
	} else if (key instanceof RSAPrivateKey) {
	RSAPrivateKey rsaKey = (RSAPrivateKey)key;
	try {
	return new RSAPrivateKeyImpl(
	RSAUtil.createAlgorithmId(type, rsaKey.getParams()),
	rsaKey.getModulus(),
	rsaKey.getPrivateExponent()
	);
	} catch (ProviderException e) {
	// catch providers that incorrectly implement RSAPrivateKey
	throw new InvalidKeyException("Invalid key", e);
	}
	} else if ("PKCS#8".equals(key.getFormat())) {
	RSAPrivateKey translated =
	RSAPrivateCrtKeyImpl.newKey(key.getEncoded());
	// ensure the key algorithm matches the current KeyFactory instance
	checkKeyAlgo(translated, type.keyAlgo());
	return translated;
	} else {
	throw new InvalidKeyException("Private keys must be instance "
	+ "of RSAPrivate(Crt)Key or have PKCS#8 encoding");
	}
	}

	// internal implementation of generatePublic. See JCA doc
	private PublicKey generatePublic(KeySpec keySpec)
	throws GeneralSecurityException {
	if (keySpec instanceof X509EncodedKeySpec) {
	X509EncodedKeySpec x509Spec = (X509EncodedKeySpec)keySpec;
	RSAPublicKey generated = new RSAPublicKeyImpl(x509Spec.getEncoded());
	// ensure the key algorithm matches the current KeyFactory instance
	checkKeyAlgo(generated, type.keyAlgo());
	return generated;
	} else if (keySpec instanceof RSAPublicKeySpec) {
	RSAPublicKeySpec rsaSpec = (RSAPublicKeySpec)keySpec;
	try {
	return new RSAPublicKeyImpl(
	RSAUtil.createAlgorithmId(type, rsaSpec.getParams()),
	rsaSpec.getModulus(),
	rsaSpec.getPublicExponent()
	);
	} catch (ProviderException e) {
	throw new InvalidKeySpecException(e);
	}
	} else {
	throw new InvalidKeySpecException("Only RSAPublicKeySpec "
	+ "and X509EncodedKeySpec supported for RSA public keys");
	}
	}

	// internal implementation of generatePrivate. See JCA doc
	private PrivateKey generatePrivate(KeySpec keySpec)
	throws GeneralSecurityException {
	if (keySpec instanceof PKCS8EncodedKeySpec) {
	PKCS8EncodedKeySpec pkcsSpec = (PKCS8EncodedKeySpec)keySpec;
	RSAPrivateKey generated = RSAPrivateCrtKeyImpl.newKey(pkcsSpec.getEncoded());
	// ensure the key algorithm matches the current KeyFactory instance
	checkKeyAlgo(generated, type.keyAlgo());
	return generated;
	} else if (keySpec instanceof RSAPrivateCrtKeySpec) {
	RSAPrivateCrtKeySpec rsaSpec = (RSAPrivateCrtKeySpec)keySpec;
	try {
	return new RSAPrivateCrtKeyImpl(
	RSAUtil.createAlgorithmId(type, rsaSpec.getParams()),
	rsaSpec.getModulus(),
	rsaSpec.getPublicExponent(),
	rsaSpec.getPrivateExponent(),
	rsaSpec.getPrimeP(),
	rsaSpec.getPrimeQ(),
	rsaSpec.getPrimeExponentP(),
	rsaSpec.getPrimeExponentQ(),
	rsaSpec.getCrtCoefficient()
	);
	} catch (ProviderException e) {
	throw new InvalidKeySpecException(e);
	}
	} else if (keySpec instanceof RSAPrivateKeySpec) {
	RSAPrivateKeySpec rsaSpec = (RSAPrivateKeySpec)keySpec;
	try {
	return new RSAPrivateKeyImpl(
	RSAUtil.createAlgorithmId(type, rsaSpec.getParams()),
	rsaSpec.getModulus(),
	rsaSpec.getPrivateExponent()
	);
	} catch (ProviderException e) {
	throw new InvalidKeySpecException(e);
	}
	} else {
	throw new InvalidKeySpecException("Only RSAPrivate(Crt)KeySpec "
	+ "and PKCS8EncodedKeySpec supported for RSA private keys");
	}
	}

	protected <T extends KeySpec> T engineGetKeySpec(Key key, Class<T> keySpec)
	throws InvalidKeySpecException {
	try {
	// convert key to one of our keys
	// this also verifies that the key is a valid RSA key and ensures
	// that the encoding is X.509/PKCS#8 for public/private keys
	key = engineTranslateKey(key);
	} catch (InvalidKeyException e) {
	throw new InvalidKeySpecException(e);
	}
	if (key instanceof RSAPublicKey) {
	RSAPublicKey rsaKey = (RSAPublicKey)key;
	if (RSA_PUB_KEYSPEC_CLS.isAssignableFrom(keySpec)) {
	return keySpec.cast(new RSAPublicKeySpec(
	rsaKey.getModulus(),
	rsaKey.getPublicExponent(),
	rsaKey.getParams()
	));
	} else if (X509_KEYSPEC_CLS.isAssignableFrom(keySpec)) {
	return keySpec.cast(new X509EncodedKeySpec(key.getEncoded()));
	} else {
	throw new InvalidKeySpecException
	("KeySpec must be RSAPublicKeySpec or "
	+ "X509EncodedKeySpec for RSA public keys");
	}
	} else if (key instanceof RSAPrivateKey) {
	if (PKCS8_KEYSPEC_CLS.isAssignableFrom(keySpec)) {
	return keySpec.cast(new PKCS8EncodedKeySpec(key.getEncoded()));
	} else if (RSA_PRIVCRT_KEYSPEC_CLS.isAssignableFrom(keySpec)) {
	if (key instanceof RSAPrivateCrtKey) {
	RSAPrivateCrtKey crtKey = (RSAPrivateCrtKey)key;
	return keySpec.cast(new RSAPrivateCrtKeySpec(
	crtKey.getModulus(),
	crtKey.getPublicExponent(),
	crtKey.getPrivateExponent(),
	crtKey.getPrimeP(),
	crtKey.getPrimeQ(),
	crtKey.getPrimeExponentP(),
	crtKey.getPrimeExponentQ(),
	crtKey.getCrtCoefficient(),
	crtKey.getParams()
	));
	} else {
	throw new InvalidKeySpecException
	("RSAPrivateCrtKeySpec can only be used with CRT keys");
	}
	} else if (RSA_PRIV_KEYSPEC_CLS.isAssignableFrom(keySpec)) {
	RSAPrivateKey rsaKey = (RSAPrivateKey)key;
	return keySpec.cast(new RSAPrivateKeySpec(
	rsaKey.getModulus(),
	rsaKey.getPrivateExponent(),
	rsaKey.getParams()
	));
	} else {
	throw new InvalidKeySpecException
	("KeySpec must be RSAPrivate(Crt)KeySpec or "
	+ "PKCS8EncodedKeySpec for RSA private keys");
	}
	} else {
	// should not occur, caught in engineTranslateKey()
	throw new InvalidKeySpecException("Neither public nor private key");
	}
	}

	public static final class Legacy extends RSAKeyFactory {
	public Legacy() {
	super(KeyType.RSA);
	}
	}

	public static final class PSS extends RSAKeyFactory {
	public PSS() {
	super(KeyType.PSS);
	}
	}
	}

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