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	/*
	* Copyright (c) 2005, 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 sun.security.provider;

	import java.security.*;
	import java.util.Arrays;

	import static sun.security.provider.ByteArrayAccess.*;
	import static sun.security.util.SecurityConstants.PROVIDER_VER;

	/**
	* The MD4 class is used to compute an MD4 message digest over a given
	* buffer of bytes. It is an implementation of the RSA Data Security Inc
	* MD4 algorithim as described in internet RFC 1320.
	*
	* <p>The MD4 algorithm is very weak and should not be used unless it is
	* unavoidable. Therefore, it is not registered in our standard providers. To
	* obtain an implementation, call the static getInstance() method in this
	* class.
	*
	* @author Andreas Sterbenz
	*/
	public final class MD4 extends DigestBase {

	// state of this object
	private int[] state;

	// rotation constants
	private static final int S11 = 3;
	private static final int S12 = 7;
	private static final int S13 = 11;
	private static final int S14 = 19;
	private static final int S21 = 3;
	private static final int S22 = 5;
	private static final int S23 = 9;
	private static final int S24 = 13;
	private static final int S31 = 3;
	private static final int S32 = 9;
	private static final int S33 = 11;
	private static final int S34 = 15;

	private static final Provider md4Provider;

	static {
	md4Provider = new Provider("MD4Provider", PROVIDER_VER,
	"MD4 MessageDigest") {
	@java.io.Serial
	private static final long serialVersionUID = -8850464997518327965L;
	};
	@SuppressWarnings("removal")
	var dummy = AccessController.doPrivileged(new PrivilegedAction<Void>() {
	public Void run() {
	md4Provider.put("MessageDigest.MD4", "sun.security.provider.MD4");
	return null;
	}
	});
	}

	public static MessageDigest getInstance() {
	try {
	return MessageDigest.getInstance("MD4", md4Provider);
	} catch (NoSuchAlgorithmException e) {
	// should never occur
	throw new ProviderException(e);
	}
	}

	// Standard constructor, creates a new MD4 instance.
	public MD4() {
	super("MD4", 16, 64);
	state = new int[4];
	resetHashes();
	}

	// clone this object
	public Object clone() throws CloneNotSupportedException {
	MD4 copy = (MD4) super.clone();
	copy.state = copy.state.clone();
	return copy;
	}

	/**
	* Reset the state of this object.
	*/
	void implReset() {
	// Load magic initialization constants.
	resetHashes();
	}

	private void resetHashes() {
	state[0] = 0x67452301;
	state[1] = 0xefcdab89;
	state[2] = 0x98badcfe;
	state[3] = 0x10325476;
	}

	/**
	* Perform the final computations, any buffered bytes are added
	* to the digest, the count is added to the digest, and the resulting
	* digest is stored.
	*/
	void implDigest(byte[] out, int ofs) {
	long bitsProcessed = bytesProcessed << 3;

	int index = (int)bytesProcessed & 0x3f;
	int padLen = (index < 56) ? (56 - index) : (120 - index);
	engineUpdate(padding, 0, padLen);

	i2bLittle4((int)bitsProcessed, buffer, 56);
	i2bLittle4((int)(bitsProcessed >>> 32), buffer, 60);
	implCompress(buffer, 0);

	i2bLittle(state, 0, out, ofs, 16);
	}

	private static int FF(int a, int b, int c, int d, int x, int s) {
	a += ((b & c) \| ((~b) & d)) + x;
	return ((a << s) \| (a >>> (32 - s)));
	}

	private static int GG(int a, int b, int c, int d, int x, int s) {
	a += ((b & c) \| (b & d) \| (c & d)) + x + 0x5a827999;
	return ((a << s) \| (a >>> (32 - s)));
	}

	private static int HH(int a, int b, int c, int d, int x, int s) {
	a += ((b ^ c) ^ d) + x + 0x6ed9eba1;
	return ((a << s) \| (a >>> (32 - s)));
	}

	/**
	* This is where the functions come together as the generic MD4
	* transformation operation. It consumes sixteen
	* bytes from the buffer, beginning at the specified offset.
	*/
	void implCompress(byte[] buf, int ofs) {
	int x0 = (int) LE.INT_ARRAY.get(buf, ofs);
	int x1 = (int) LE.INT_ARRAY.get(buf, ofs + 4);
	int x2 = (int) LE.INT_ARRAY.get(buf, ofs + 8);
	int x3 = (int) LE.INT_ARRAY.get(buf, ofs + 12);
	int x4 = (int) LE.INT_ARRAY.get(buf, ofs + 16);
	int x5 = (int) LE.INT_ARRAY.get(buf, ofs + 20);
	int x6 = (int) LE.INT_ARRAY.get(buf, ofs + 24);
	int x7 = (int) LE.INT_ARRAY.get(buf, ofs + 28);
	int x8 = (int) LE.INT_ARRAY.get(buf, ofs + 32);
	int x9 = (int) LE.INT_ARRAY.get(buf, ofs + 36);
	int x10 = (int) LE.INT_ARRAY.get(buf, ofs + 40);
	int x11 = (int) LE.INT_ARRAY.get(buf, ofs + 44);
	int x12 = (int) LE.INT_ARRAY.get(buf, ofs + 48);
	int x13 = (int) LE.INT_ARRAY.get(buf, ofs + 52);
	int x14 = (int) LE.INT_ARRAY.get(buf, ofs + 56);
	int x15 = (int) LE.INT_ARRAY.get(buf, ofs + 60);

	int a = state[0];
	int b = state[1];
	int c = state[2];
	int d = state[3];

	/* Round 1 */
	a = FF (a, b, c, d, x0, S11); /* 1 */
	d = FF (d, a, b, c, x1, S12); /* 2 */
	c = FF (c, d, a, b, x2, S13); /* 3 */
	b = FF (b, c, d, a, x3, S14); /* 4 */
	a = FF (a, b, c, d, x4, S11); /* 5 */
	d = FF (d, a, b, c, x5, S12); /* 6 */
	c = FF (c, d, a, b, x6, S13); /* 7 */
	b = FF (b, c, d, a, x7, S14); /* 8 */
	a = FF (a, b, c, d, x8, S11); /* 9 */
	d = FF (d, a, b, c, x9, S12); /* 10 */
	c = FF (c, d, a, b, x10, S13); /* 11 */
	b = FF (b, c, d, a, x11, S14); /* 12 */
	a = FF (a, b, c, d, x12, S11); /* 13 */
	d = FF (d, a, b, c, x13, S12); /* 14 */
	c = FF (c, d, a, b, x14, S13); /* 15 */
	b = FF (b, c, d, a, x15, S14); /* 16 */

	/* Round 2 */
	a = GG (a, b, c, d, x0, S21); /* 17 */
	d = GG (d, a, b, c, x4, S22); /* 18 */
	c = GG (c, d, a, b, x8, S23); /* 19 */
	b = GG (b, c, d, a, x12, S24); /* 20 */
	a = GG (a, b, c, d, x1, S21); /* 21 */
	d = GG (d, a, b, c, x5, S22); /* 22 */
	c = GG (c, d, a, b, x9, S23); /* 23 */
	b = GG (b, c, d, a, x13, S24); /* 24 */
	a = GG (a, b, c, d, x2, S21); /* 25 */
	d = GG (d, a, b, c, x6, S22); /* 26 */
	c = GG (c, d, a, b, x10, S23); /* 27 */
	b = GG (b, c, d, a, x14, S24); /* 28 */
	a = GG (a, b, c, d, x3, S21); /* 29 */
	d = GG (d, a, b, c, x7, S22); /* 30 */
	c = GG (c, d, a, b, x11, S23); /* 31 */
	b = GG (b, c, d, a, x15, S24); /* 32 */

	/* Round 3 */
	a = HH (a, b, c, d, x0, S31); /* 33 */
	d = HH (d, a, b, c, x8, S32); /* 34 */
	c = HH (c, d, a, b, x4, S33); /* 35 */
	b = HH (b, c, d, a, x12, S34); /* 36 */
	a = HH (a, b, c, d, x2, S31); /* 37 */
	d = HH (d, a, b, c, x10, S32); /* 38 */
	c = HH (c, d, a, b, x6, S33); /* 39 */
	b = HH (b, c, d, a, x14, S34); /* 40 */
	a = HH (a, b, c, d, x1, S31); /* 41 */
	d = HH (d, a, b, c, x9, S32); /* 42 */
	c = HH (c, d, a, b, x5, S33); /* 43 */
	b = HH (b, c, d, a, x13, S34); /* 44 */
	a = HH (a, b, c, d, x3, S31); /* 45 */
	d = HH (d, a, b, c, x11, S32); /* 46 */
	c = HH (c, d, a, b, x7, S33); /* 47 */
	b = HH (b, c, d, a, x15, S34); /* 48 */

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	}

	}

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