1/*
2 * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.security.provider;
27
28import java.util.Objects;
29
30import jdk.internal.HotSpotIntrinsicCandidate;
31import static sun.security.provider.ByteArrayAccess.*;
32
33/**
34 * This class implements the Secure Hash Algorithm SHA-256 developed by
35 * the National Institute of Standards and Technology along with the
36 * National Security Agency.
37 *
38 * <p>It implements java.security.MessageDigestSpi, and can be used
39 * through Java Cryptography Architecture (JCA), as a pluggable
40 * MessageDigest implementation.
41 *
42 * @since       1.4.2
43 * @author      Valerie Peng
44 * @author      Andreas Sterbenz
45 */
46abstract class SHA2 extends DigestBase {
47
48    private static final int ITERATION = 64;
49    // Constants for each round
50    private static final int[] ROUND_CONSTS = {
51        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
52        0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
53        0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
54        0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
55        0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
56        0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
57        0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
58        0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
59        0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
60        0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
61        0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
62        0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
63        0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
64        0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
65        0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
66        0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
67    };
68
69    // buffer used by implCompress()
70    private int[] W;
71
72    // state of this object
73    private int[] state;
74
75    // initial state value. different between SHA-224 and SHA-256
76    private final int[] initialHashes;
77
78    /**
79     * Creates a new SHA object.
80     */
81    SHA2(String name, int digestLength, int[] initialHashes) {
82        super(name, digestLength, 64);
83        this.initialHashes = initialHashes;
84        state = new int[8];
85        W = new int[64];
86        implReset();
87    }
88
89    /**
90     * Resets the buffers and hash value to start a new hash.
91     */
92    void implReset() {
93        System.arraycopy(initialHashes, 0, state, 0, state.length);
94    }
95
96    void implDigest(byte[] out, int ofs) {
97        long bitsProcessed = bytesProcessed << 3;
98
99        int index = (int)bytesProcessed & 0x3f;
100        int padLen = (index < 56) ? (56 - index) : (120 - index);
101        engineUpdate(padding, 0, padLen);
102
103        i2bBig4((int)(bitsProcessed >>> 32), buffer, 56);
104        i2bBig4((int)bitsProcessed, buffer, 60);
105        implCompress(buffer, 0);
106
107        i2bBig(state, 0, out, ofs, engineGetDigestLength());
108    }
109
110    /**
111     * logical function ch(x,y,z) as defined in spec:
112     * @return (x and y) xor ((complement x) and z)
113     * @param x int
114     * @param y int
115     * @param z int
116     */
117    private static int lf_ch(int x, int y, int z) {
118        return (x & y) ^ ((~x) & z);
119    }
120
121    /**
122     * logical function maj(x,y,z) as defined in spec:
123     * @return (x and y) xor (x and z) xor (y and z)
124     * @param x int
125     * @param y int
126     * @param z int
127     */
128    private static int lf_maj(int x, int y, int z) {
129        return (x & y) ^ (x & z) ^ (y & z);
130    }
131
132    /**
133     * logical function R(x,s) - right shift
134     * @return x right shift for s times
135     * @param x int
136     * @param s int
137     */
138    private static int lf_R( int x, int s ) {
139        return (x >>> s);
140    }
141
142    /**
143     * logical function S(x,s) - right rotation
144     * @return x circular right shift for s times
145     * @param x int
146     * @param s int
147     */
148    private static int lf_S(int x, int s) {
149        return (x >>> s) | (x << (32 - s));
150    }
151
152    /**
153     * logical function sigma0(x) - xor of results of right rotations
154     * @return S(x,2) xor S(x,13) xor S(x,22)
155     * @param x int
156     */
157    private static int lf_sigma0(int x) {
158        return lf_S(x, 2) ^ lf_S(x, 13) ^ lf_S(x, 22);
159    }
160
161    /**
162     * logical function sigma1(x) - xor of results of right rotations
163     * @return S(x,6) xor S(x,11) xor S(x,25)
164     * @param x int
165     */
166    private static int lf_sigma1(int x) {
167        return lf_S( x, 6 ) ^ lf_S( x, 11 ) ^ lf_S( x, 25 );
168    }
169
170    /**
171     * logical function delta0(x) - xor of results of right shifts/rotations
172     * @return int
173     * @param x int
174     */
175    private static int lf_delta0(int x) {
176        return lf_S(x, 7) ^ lf_S(x, 18) ^ lf_R(x, 3);
177    }
178
179    /**
180     * logical function delta1(x) - xor of results of right shifts/rotations
181     * @return int
182     * @param x int
183     */
184    private static int lf_delta1(int x) {
185        return lf_S(x, 17) ^ lf_S(x, 19) ^ lf_R(x, 10);
186    }
187
188    /**
189     * Process the current block to update the state variable state.
190     */
191    void implCompress(byte[] buf, int ofs) {
192        implCompressCheck(buf, ofs);
193        implCompress0(buf, ofs);
194    }
195
196    private void implCompressCheck(byte[] buf, int ofs) {
197        Objects.requireNonNull(buf);
198
199        // The checks performed by the method 'b2iBig64'
200        // are sufficient for the case when the method
201        // 'implCompressImpl' is replaced with a compiler
202        // intrinsic.
203        b2iBig64(buf, ofs, W);
204    }
205
206    // The method 'implCompressImpl' seems not to use its parameters.
207    // The method can, however, be replaced with a compiler intrinsic
208    // that operates directly on the array 'buf' (starting from
209    // offset 'ofs') and not on array 'W', therefore 'buf' and 'ofs'
210    // must be passed as parameter to the method.
211    @HotSpotIntrinsicCandidate
212    private void implCompress0(byte[] buf, int ofs) {
213        // The first 16 ints are from the byte stream, compute the rest of
214        // the W[]'s
215        for (int t = 16; t < ITERATION; t++) {
216            W[t] = lf_delta1(W[t-2]) + W[t-7] + lf_delta0(W[t-15])
217                   + W[t-16];
218        }
219
220        int a = state[0];
221        int b = state[1];
222        int c = state[2];
223        int d = state[3];
224        int e = state[4];
225        int f = state[5];
226        int g = state[6];
227        int h = state[7];
228
229        for (int i = 0; i < ITERATION; i++) {
230            int T1 = h + lf_sigma1(e) + lf_ch(e,f,g) + ROUND_CONSTS[i] + W[i];
231            int T2 = lf_sigma0(a) + lf_maj(a,b,c);
232            h = g;
233            g = f;
234            f = e;
235            e = d + T1;
236            d = c;
237            c = b;
238            b = a;
239            a = T1 + T2;
240        }
241        state[0] += a;
242        state[1] += b;
243        state[2] += c;
244        state[3] += d;
245        state[4] += e;
246        state[5] += f;
247        state[6] += g;
248        state[7] += h;
249    }
250
251    public Object clone() throws CloneNotSupportedException {
252        SHA2 copy = (SHA2) super.clone();
253        copy.state = copy.state.clone();
254        copy.W = new int[64];
255        return copy;
256    }
257
258    /**
259     * SHA-224 implementation class.
260     */
261    public static final class SHA224 extends SHA2 {
262        private static final int[] INITIAL_HASHES = {
263            0xc1059ed8, 0x367cd507, 0x3070dd17, 0xf70e5939,
264            0xffc00b31, 0x68581511, 0x64f98fa7, 0xbefa4fa4
265        };
266
267        public SHA224() {
268            super("SHA-224", 28, INITIAL_HASHES);
269        }
270    }
271
272    /**
273     * SHA-256 implementation class.
274     */
275    public static final class SHA256 extends SHA2 {
276        private static final int[] INITIAL_HASHES = {
277            0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
278            0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
279        };
280
281        public SHA256() {
282            super("SHA-256", 32, INITIAL_HASHES);
283        }
284    }
285}
286