001: package org.bouncycastle.crypto.digests;
002:
003: import org.bouncycastle.crypto.digests.GeneralDigest;
004:
005: /**
006: * FIPS 180-2 implementation of SHA-256.
007: *
008: * <pre>
009: * block word digest
010: * SHA-1 512 32 160
011: * SHA-256 512 32 256
012: * SHA-384 1024 64 384
013: * SHA-512 1024 64 512
014: * </pre>
015: */
016: public class SHA256Digest extends GeneralDigest {
017: private static final int DIGEST_LENGTH = 32;
018:
019: private int H1, H2, H3, H4, H5, H6, H7, H8;
020:
021: private int[] X = new int[64];
022: private int xOff;
023:
024: /**
025: * Standard constructor
026: */
027: public SHA256Digest() {
028: reset();
029: }
030:
031: /**
032: * Copy constructor. This will copy the state of the provided
033: * message digest.
034: */
035: public SHA256Digest(SHA256Digest t) {
036: super (t);
037:
038: H1 = t.H1;
039: H2 = t.H2;
040: H3 = t.H3;
041: H4 = t.H4;
042: H5 = t.H5;
043: H6 = t.H6;
044: H7 = t.H7;
045: H8 = t.H8;
046:
047: System.arraycopy(t.X, 0, X, 0, t.X.length);
048: xOff = t.xOff;
049: }
050:
051: public String getAlgorithmName() {
052: return "SHA-256";
053: }
054:
055: public int getDigestSize() {
056: return DIGEST_LENGTH;
057: }
058:
059: protected void processWord(byte[] in, int inOff) {
060: X[xOff++] = ((in[inOff] & 0xff) << 24)
061: | ((in[inOff + 1] & 0xff) << 16)
062: | ((in[inOff + 2] & 0xff) << 8)
063: | ((in[inOff + 3] & 0xff));
064:
065: if (xOff == 16) {
066: processBlock();
067: }
068: }
069:
070: private void unpackWord(int word, byte[] out, int outOff) {
071: out[outOff] = (byte) (word >>> 24);
072: out[outOff + 1] = (byte) (word >>> 16);
073: out[outOff + 2] = (byte) (word >>> 8);
074: out[outOff + 3] = (byte) word;
075: }
076:
077: protected void processLength(long bitLength) {
078: if (xOff > 14) {
079: processBlock();
080: }
081:
082: X[14] = (int) (bitLength >>> 32);
083: X[15] = (int) (bitLength & 0xffffffff);
084: }
085:
086: public int doFinal(byte[] out, int outOff) {
087: finish();
088:
089: unpackWord(H1, out, outOff);
090: unpackWord(H2, out, outOff + 4);
091: unpackWord(H3, out, outOff + 8);
092: unpackWord(H4, out, outOff + 12);
093: unpackWord(H5, out, outOff + 16);
094: unpackWord(H6, out, outOff + 20);
095: unpackWord(H7, out, outOff + 24);
096: unpackWord(H8, out, outOff + 28);
097:
098: reset();
099:
100: return DIGEST_LENGTH;
101: }
102:
103: /**
104: * reset the chaining variables
105: */
106: public void reset() {
107: super .reset();
108:
109: /* SHA-256 initial hash value
110: * The first 32 bits of the fractional parts of the square roots
111: * of the first eight prime numbers
112: */
113:
114: H1 = 0x6a09e667;
115: H2 = 0xbb67ae85;
116: H3 = 0x3c6ef372;
117: H4 = 0xa54ff53a;
118: H5 = 0x510e527f;
119: H6 = 0x9b05688c;
120: H7 = 0x1f83d9ab;
121: H8 = 0x5be0cd19;
122:
123: xOff = 0;
124: for (int i = 0; i != X.length; i++) {
125: X[i] = 0;
126: }
127: }
128:
129: protected void processBlock() {
130: //
131: // expand 16 word block into 64 word blocks.
132: //
133: for (int t = 16; t <= 63; t++) {
134: X[t] = Theta1(X[t - 2]) + X[t - 7] + Theta0(X[t - 15])
135: + X[t - 16];
136: }
137:
138: //
139: // set up working variables.
140: //
141: int a = H1;
142: int b = H2;
143: int c = H3;
144: int d = H4;
145: int e = H5;
146: int f = H6;
147: int g = H7;
148: int h = H8;
149:
150: int t = 0;
151: for (int i = 0; i < 8; i++) {
152: // t = 8 * i
153: h += Sum1(e) + Ch(e, f, g) + K[t] + X[t++];
154: d += h;
155: h += Sum0(a) + Maj(a, b, c);
156:
157: // t = 8 * i + 1
158: g += Sum1(d) + Ch(d, e, f) + K[t] + X[t++];
159: c += g;
160: g += Sum0(h) + Maj(h, a, b);
161:
162: // t = 8 * i + 2
163: f += Sum1(c) + Ch(c, d, e) + K[t] + X[t++];
164: b += f;
165: f += Sum0(g) + Maj(g, h, a);
166:
167: // t = 8 * i + 3
168: e += Sum1(b) + Ch(b, c, d) + K[t] + X[t++];
169: a += e;
170: e += Sum0(f) + Maj(f, g, h);
171:
172: // t = 8 * i + 4
173: d += Sum1(a) + Ch(a, b, c) + K[t] + X[t++];
174: h += d;
175: d += Sum0(e) + Maj(e, f, g);
176:
177: // t = 8 * i + 5
178: c += Sum1(h) + Ch(h, a, b) + K[t] + X[t++];
179: g += c;
180: c += Sum0(d) + Maj(d, e, f);
181:
182: // t = 8 * i + 6
183: b += Sum1(g) + Ch(g, h, a) + K[t] + X[t++];
184: f += b;
185: b += Sum0(c) + Maj(c, d, e);
186:
187: // t = 8 * i + 7
188: a += Sum1(f) + Ch(f, g, h) + K[t] + X[t++];
189: e += a;
190: a += Sum0(b) + Maj(b, c, d);
191: }
192:
193: H1 += a;
194: H2 += b;
195: H3 += c;
196: H4 += d;
197: H5 += e;
198: H6 += f;
199: H7 += g;
200: H8 += h;
201:
202: //
203: // reset the offset and clean out the word buffer.
204: //
205: xOff = 0;
206: for (int i = 0; i < 16; i++) {
207: X[i] = 0;
208: }
209: }
210:
211: /* SHA-256 functions */
212: private int Ch(int x, int y, int z) {
213: return (x & y) ^ ((~x) & z);
214: }
215:
216: private int Maj(int x, int y, int z) {
217: return (x & y) ^ (x & z) ^ (y & z);
218: }
219:
220: private int Sum0(int x) {
221: return ((x >>> 2) | (x << 30)) ^ ((x >>> 13) | (x << 19))
222: ^ ((x >>> 22) | (x << 10));
223: }
224:
225: private int Sum1(int x) {
226: return ((x >>> 6) | (x << 26)) ^ ((x >>> 11) | (x << 21))
227: ^ ((x >>> 25) | (x << 7));
228: }
229:
230: private int Theta0(int x) {
231: return ((x >>> 7) | (x << 25)) ^ ((x >>> 18) | (x << 14))
232: ^ (x >>> 3);
233: }
234:
235: private int Theta1(int x) {
236: return ((x >>> 17) | (x << 15)) ^ ((x >>> 19) | (x << 13))
237: ^ (x >>> 10);
238: }
239:
240: /* SHA-256 Constants
241: * (represent the first 32 bits of the fractional parts of the
242: * cube roots of the first sixty-four prime numbers)
243: */
244: static final int K[] = { 0x428a2f98, 0x71374491, 0xb5c0fbcf,
245: 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
246: 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74,
247: 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
248: 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc,
249: 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
250: 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85,
251: 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb,
252: 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70,
253: 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
254: 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3,
255: 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f,
256: 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7,
257: 0xc67178f2 };
258: }
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