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	/*
	* Copyright (c) 2002, 2013, 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.util.Arrays;

	import java.util.Objects;

	import static sun.security.provider.ByteArrayAccess.*;

	/**
	* This class implements the Secure Hash Algorithm SHA-256 developed by
	* the National Institute of Standards and Technology along with the
	* National Security Agency.
	*
	* <p>It implements java.security.MessageDigestSpi, and can be used
	* through Java Cryptography Architecture (JCA), as a pluggable
	* MessageDigest implementation.
	*
	* @since 1.4.2
	* @author Valerie Peng
	* @author Andreas Sterbenz
	*/
	abstract class SHA2 extends DigestBase {

	private static final int ITERATION = 64;
	// Constants for each round
	private static final int[] ROUND_CONSTS = {
	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
	0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
	0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
	0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
	0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
	0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
	0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
	0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
	0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
	0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
	0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
	0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
	0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
	0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
	};

	// buffer used by implCompress()
	private int[] W;

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

	// initial state value. different between SHA-224 and SHA-256
	private final int[] initialHashes;

	/**
	* Creates a new SHA object.
	*/
	SHA2(String name, int digestLength, int[] initialHashes) {
	super(name, digestLength, 64);
	this.initialHashes = initialHashes;
	state = new int[8];
	W = new int[64];
	resetHashes();
	}

	/**
	* Resets the buffers and hash value to start a new hash.
	*/
	void implReset() {
	resetHashes();
	Arrays.fill(W, 0);
	}

	private void resetHashes() {
	System.arraycopy(initialHashes, 0, state, 0, state.length);
	}

	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);

	i2bBig4((int)(bitsProcessed >>> 32), buffer, 56);
	i2bBig4((int)bitsProcessed, buffer, 60);
	implCompress(buffer, 0);

	i2bBig(state, 0, out, ofs, engineGetDigestLength());
	}

	/**
	* logical function ch(x,y,z) as defined in spec:
	* @return (x and y) xor ((complement x) and z)
	* @param x int
	* @param y int
	* @param z int
	*/
	private static int lf_ch(int x, int y, int z) {
	return (x & y) ^ ((~x) & z);
	}

	/**
	* logical function maj(x,y,z) as defined in spec:
	* @return (x and y) xor (x and z) xor (y and z)
	* @param x int
	* @param y int
	* @param z int
	*/
	private static int lf_maj(int x, int y, int z) {
	return (x & y) ^ (x & z) ^ (y & z);
	}

	/**
	* logical function R(x,s) - right shift
	* @return x right shift for s times
	* @param x int
	* @param s int
	*/
	private static int lf_R( int x, int s ) {
	return (x >>> s);
	}

	/**
	* logical function S(x,s) - right rotation
	* @return x circular right shift for s times
	* @param x int
	* @param s int
	*/
	private static int lf_S(int x, int s) {
	return (x >>> s) \| (x << (32 - s));
	}

	/**
	* logical function sigma0(x) - xor of results of right rotations
	* @return S(x,2) xor S(x,13) xor S(x,22)
	* @param x int
	*/
	private static int lf_sigma0(int x) {
	return lf_S(x, 2) ^ lf_S(x, 13) ^ lf_S(x, 22);
	}

	/**
	* logical function sigma1(x) - xor of results of right rotations
	* @return S(x,6) xor S(x,11) xor S(x,25)
	* @param x int
	*/
	private static int lf_sigma1(int x) {
	return lf_S( x, 6 ) ^ lf_S( x, 11 ) ^ lf_S( x, 25 );
	}

	/**
	* logical function delta0(x) - xor of results of right shifts/rotations
	* @return int
	* @param x int
	*/
	private static int lf_delta0(int x) {
	return lf_S(x, 7) ^ lf_S(x, 18) ^ lf_R(x, 3);
	}

	/**
	* logical function delta1(x) - xor of results of right shifts/rotations
	* @return int
	* @param x int
	*/
	private static int lf_delta1(int x) {
	return lf_S(x, 17) ^ lf_S(x, 19) ^ lf_R(x, 10);
	}

	/**
	* Process the current block to update the state variable state.
	*/
	void implCompress(byte[] buf, int ofs) {
	implCompressCheck(buf, ofs);
	implCompress0(buf, ofs);
	}

	private void implCompressCheck(byte[] buf, int ofs) {
	Objects.requireNonNull(buf);

	// The checks performed by the method 'b2iBig64'
	// are sufficient for the case when the method
	// 'implCompressImpl' is replaced with a compiler
	// intrinsic.
	b2iBig64(buf, ofs, W);
	}

	// The method 'implCompressImpl' seems not to use its parameters.
	// The method can, however, be replaced with a compiler intrinsic
	// that operates directly on the array 'buf' (starting from
	// offset 'ofs') and not on array 'W', therefore 'buf' and 'ofs'
	// must be passed as parameter to the method.
	private void implCompress0(byte[] buf, int ofs) {
	// The first 16 ints are from the byte stream, compute the rest of
	// the W[]'s
	for (int t = 16; t < ITERATION; t++) {
	W[t] = lf_delta1(W[t-2]) + W[t-7] + lf_delta0(W[t-15])
	+ W[t-16];
	}

	int a = state[0];
	int b = state[1];
	int c = state[2];
	int d = state[3];
	int e = state[4];
	int f = state[5];
	int g = state[6];
	int h = state[7];

	for (int i = 0; i < ITERATION; i++) {
	int T1 = h + lf_sigma1(e) + lf_ch(e,f,g) + ROUND_CONSTS[i] + W[i];
	int T2 = lf_sigma0(a) + lf_maj(a,b,c);
	h = g;
	g = f;
	f = e;
	e = d + T1;
	d = c;
	c = b;
	b = a;
	a = T1 + T2;
	}
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;
	state[5] += f;
	state[6] += g;
	state[7] += h;
	}

	public Object clone() throws CloneNotSupportedException {
	SHA2 copy = (SHA2) super.clone();
	copy.state = copy.state.clone();
	copy.W = new int[64];
	return copy;
	}

	/**
	* SHA-224 implementation class.
	*/
	public static final class SHA224 extends SHA2 {
	private static final int[] INITIAL_HASHES = {
	0xc1059ed8, 0x367cd507, 0x3070dd17, 0xf70e5939,
	0xffc00b31, 0x68581511, 0x64f98fa7, 0xbefa4fa4
	};

	public SHA224() {
	super("SHA-224", 28, INITIAL_HASHES);
	}
	}

	/**
	* SHA-256 implementation class.
	*/
	public static final class SHA256 extends SHA2 {
	private static final int[] INITIAL_HASHES = {
	0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
	0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
	};

	public SHA256() {
	super("SHA-256", 32, INITIAL_HASHES);
	}
	}
	}

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