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/* * Copyright (c) 2002, 2006, 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 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 */public final 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 final int[] W;     // state of this object    private final int[] state;     /**     * Creates a new SHA object.     */    public SHA2() {        super("SHA-256", 32, 64);        state = new int[8];        W = new int[64];        implReset();    }     /**     * Creates a SHA2 object.with state (for cloning)     */    private SHA2(SHA2 base) {        super(base);        this.state = base.state.clone();        this.W = new int[64];    }     public Object clone() {        return new SHA2(this);    }     /**     * Resets the buffers and hash value to start a new hash.     */    void implReset() {        state[0] = 0x6a09e667;        state[1] = 0xbb67ae85;        state[2] = 0x3c6ef372;        state[3] = 0xa54ff53a;        state[4] = 0x510e527f;        state[5] = 0x9b05688c;        state[6] = 0x1f83d9ab;        state[7] = 0x5be0cd19;    }     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, 32);    }     /**     * 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) {        b2iBig64(buf, ofs, W);         // 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;    } }