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	/*
	* Copyright (c) 2021, 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.util.Arrays;
	import java.security.*;
	import java.security.spec.*;
	import javax.crypto.*;
	import javax.crypto.spec.*;
	import static com.sun.crypto.provider.KWUtil.*;

	/**
	* This class implement the AES KeyWrap mode of operation as defined in
	* <a href=https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-38F.pdf>
	* "Recommendation for Block Cipher Modes of Operation: Methods for Key Wrapping"</a>
	* and represents AES cipher in KW mode.
	*/
	class AESKeyWrap extends FeedbackCipher {

	// default integrity check value (icv) if iv is not supplied
	static final byte[] ICV1 = { // SEMI_BLKSIZE long
	(byte) 0xA6, (byte) 0xA6, (byte) 0xA6, (byte) 0xA6,
	(byte) 0xA6, (byte) 0xA6, (byte) 0xA6, (byte) 0xA6
	};

	AESKeyWrap() {
	super(new AESCrypt());
	}

	/**
	* Gets the name of this feedback mode.
	*
	* @return the string <code>KW</code>
	*/
	@Override
	String getFeedback() {
	return "KW";
	}

	/**
	* Save the current content of this cipher.
	*/
	@Override
	void save() {
	throw new UnsupportedOperationException("save not supported");
	};

	/**
	* Restores the content of this cipher to the previous saved one.
	*/
	@Override
	void restore() {
	throw new UnsupportedOperationException("restore not supported");
	};

	/**
	* Initializes the cipher in the specified mode with the given key
	* and iv.
	*
	* @param decrypting flag indicating encryption or decryption
	* @param algorithm the algorithm name
	* @param key the key
	* @param iv the iv
	*
	* @exception InvalidKeyException if the given key is inappropriate for
	* initializing this cipher
	* @exception InvalidAlgorithmParameterException if the given iv is
	* non-null and not the right length
	*/
	@Override
	void init(boolean decrypting, String algorithm, byte[] key, byte[] iv)
	throws InvalidKeyException, InvalidAlgorithmParameterException {
	if (key == null) {
	throw new InvalidKeyException("Invalid null key");
	}
	if (iv != null && iv.length != SEMI_BLKSIZE) {
	throw new InvalidAlgorithmParameterException("Invalid IV");
	}
	embeddedCipher.init(decrypting, algorithm, key);
	// iv is retrieved from IvParameterSpec.getIV() which is already cloned
	this.iv = (iv == null? ICV1 : iv);
	}

	/**
	* Resets the iv to its original value.
	* This is used when doFinal is called in the Cipher class, so that the
	* cipher can be reused (with its original iv).
	*/
	@Override
	void reset() {
	throw new UnsupportedOperationException("reset not supported");
	};


	// no support for multi-part encryption
	@Override
	int encrypt(byte[] pt, int ptOfs, int ptLen, byte[] ct, int ctOfs) {
	throw new UnsupportedOperationException("multi-part not supported");
	};

	// no support for multi-part decryption
	@Override
	int decrypt(byte[] ct, int ctOfs, int ctLen, byte[] pt, int ptOfs) {
	throw new UnsupportedOperationException("multi-part not supported");
	};

	/**
	* Performs single-part encryption operation.
	*
	* <p>The input <code>pt</code>, starting at <code>0</code>
	* and ending at <code>ptLen-1</code>, is encrypted.
	* The result is stored in place into <code>pt</code>, starting at
	* <code>0</code>.
	*
	* <p>The subclass that implements Cipher should ensure that
	* <code>init</code> has been called before this method is called.
	*
	* @param pt the input buffer with the data to be encrypted
	* @param dummy1 the offset in <code>pt</code> which is always 0
	* @param ptLen the length of the input data
	* @param dummy2 the output buffer for the encryption which is always pt
	* @param dummy3 the offset in the output buffer which is always 0
	* @return the number of bytes placed into <code>pt</code>
	*/
	@Override
	int encryptFinal(byte[] pt, int dummy1, int ptLen, byte[] dummy2,
	int dummy3) throws IllegalBlockSizeException {
	// adjust the min value since pt contains the first semi-block
	if (ptLen < MIN_INPUTLEN \|\| (ptLen % SEMI_BLKSIZE) != 0) {
	throw new IllegalBlockSizeException("data should" +
	" be at least 16 bytes and multiples of 8");
	}
	return W(iv, pt, ptLen, embeddedCipher);
	}

	/**
	* Performs single-part decryption operation.
	*
	* <p>The input <code>ct</code>, starting at <code>0</code>
	* and ending at <code>ctLen-1</code>, is decrypted.
	* The result is stored in place into <code>ct</code>, starting at
	* <code>0</code>.
	*
	* <p>NOTE: Purpose of this special impl is for minimizing array
	* copying, those unused arguments are named as dummyN.
	*
	* <p>The subclass that implements Cipher should ensure that
	* <code>init</code> has been called before this method is called.
	*
	* @param ct the input buffer with the data to be decrypted
	* @param dummy1 the offset in <code>ct</code> which is always 0
	* @param ctLen the length of the input data
	* @param dummy2 the output buffer for the decryption which is always ct
	* @param dummy3 the offset in the output buffer which is always 0
	* @return the number of bytes placed into <code>ct</code>
	*/
	@Override
	int decryptFinal(byte[] ct, int dummy1, int ctLen, byte[] dummy2,
	int dummy3) throws IllegalBlockSizeException {
	if (ctLen < MIN_INPUTLEN \|\| (ctLen % SEMI_BLKSIZE) != 0) {
	throw new IllegalBlockSizeException
	("data should be at least 24 bytes and multiples of 8");
	}
	byte[] ivOut = new byte[SEMI_BLKSIZE];
	ctLen = W_INV(ct, ctLen, ivOut, embeddedCipher);

	// check against icv and fail if not match
	if (!MessageDigest.isEqual(ivOut, this.iv)) {
	throw new IllegalBlockSizeException("Integrity check failed");
	}
	return ctLen;
	}
	}

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