libjava/gnu/java/security/provider/SHA.java

   1 /* SHA.java -- Class implementing the SHA-1 algorithm as specified in [1].
   2    Copyright (C) 1999, 2000, 2002 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package gnu.java.security.provider;
  40
  41 import java.security.MessageDigest;
  42
  43 /**
  44    This class implements the SHA-1 algorithm as described in [1].
  45
  46    [1] Federal Information Processing Standards Publication 180-1.
  47    Specifications for the Secure Hash Standard.  April 17, 1995.
  48
  49    @see java.security.MessageDigest
  50 */
  51 public class SHA extends MessageDigest implements Cloneable
  52 {
  53   public SHA ()
  54   {
  55     super("SHA");
  56     engineReset ();
  57   }
  58
  59   public int engineGetDigestLength()
  60   {
  61     return 20;
  62   }
  63
  64   public void engineUpdate (byte b)
  65   {
  66     int i = ((int)bytecount) & 0x3f; //wgs
  67     int shift = (3 - i % 4) << 3;
  68     int idx = i / 4;
  69
  70     i = (int)b;
  71     W[idx] = (W[idx] & ~(0xff << shift)) | ((i & 0xff) << shift);
  72
  73     // if we've filled up a block, then process it
  74     if (((++bytecount) & 0x3f) == 0)
  75       munch ();
  76   }
  77
  78   // This could be optimized.
  79   public void engineUpdate (byte bytes[], int off, int len)
  80   {
  81     if (len < 0)
  82       throw new ArrayIndexOutOfBoundsException ();
  83
  84     int end = off + len;
  85     while (off < end)
  86       engineUpdate (bytes[off++]);
  87   }
  88
  89   public void engineReset ()
  90   {
  91     bytecount = 0;
  92     // magic numbers from [1] p. 10.
  93     H0 = 0x67452301;
  94     H1 = 0xefcdab89;
  95     H2 = 0x98badcfe;
  96     H3 = 0x10325476;
  97     H4 = 0xc3d2e1f0;
  98   }
  99
 100   public byte[] engineDigest ()
 101   {
 102     long bitcount = bytecount << 3;
 103     engineUpdate ((byte)0x80); // 10000000 in binary; the start of the padding
 104
 105     // add the rest of the padding to fill this block out, but leave 8
 106     // bytes to put in the original bytecount
 107     while ((bytecount & 0x3f) != 56)
 108       engineUpdate ((byte)0);
 109
 110     // add the length of the original, unpadded block to the end of
 111     // the padding
 112     W[14] = (int)(bitcount >>> 32);
 113     W[15] = (int)bitcount;
 114     bytecount += 8;
 115
 116     // digest the fully padded block
 117     munch ();
 118
 119     byte[] result
 120       = new byte[] {(byte)(H0 >>> 24), (byte)(H0 >>> 16),
 121                     (byte)(H0 >>> 8), (byte)H0,
 122                     (byte)(H1 >>> 24), (byte)(H1 >>> 16),
 123                     (byte)(H1 >>> 8), (byte)H1,
 124                     (byte)(H2 >>> 24), (byte)(H2 >>> 16),
 125                     (byte)(H2 >>> 8), (byte)H2,
 126                     (byte)(H3 >>> 24), (byte)(H3 >>> 16),
 127                     (byte)(H3 >>> 8), (byte)H3,
 128                     (byte)(H4 >>> 24), (byte)(H4 >>> 16),
 129                     (byte)(H4 >>> 8), (byte)H4};
 130
 131     engineReset ();
 132     return result;
 133   }
 134
 135   // Process a single block.  This is pretty much copied verbatim from
 136   // [1] pp. 9, 10.
 137   private void munch ()
 138   {
 139     for (int t = 16; t < 80; ++ t)
 140       {
 141         int Wt = W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16];
 142         W[t] = Wt << 1 | Wt >>> 31;
 143       }
 144
 145     int A = H0;
 146     int B = H1;
 147     int C = H2;
 148     int D = H3;
 149     int E = H4;
 150
 151     for (int t = 0; t < 20; ++ t)
 152       {
 153         int TEMP = (A << 5 | A >>> 27) // S^5(A)
 154           + ((B & C) | (~B & D))       // f_t(B,C,D)
 155           + E + W[t]
 156           + 0x5a827999;                // K_t
 157
 158         E = D;
 159         D = C;
 160         C = B << 30 | B >>> 2;         // S^30(B)
 161         B = A;
 162         A = TEMP;
 163       }
 164
 165     for (int t = 20; t < 40; ++ t)
 166       {
 167         int TEMP = (A << 5 | A >>> 27) // S^5(A)
 168           + (B ^ C ^ D)                // f_t(B,C,D)
 169           + E + W[t]
 170           + 0x6ed9eba1;                // K_t
 171
 172         E = D;
 173         D = C;
 174         C = B << 30 | B >>> 2;         // S^30(B)
 175         B = A;
 176         A = TEMP;
 177       }
 178
 179     for (int t = 40; t < 60; ++ t)
 180       {
 181         int TEMP = (A << 5 | A >>> 27) // S^5(A)
 182           + (B & C | B & D | C & D)    // f_t(B,C,D)
 183           + E + W[t]
 184           + 0x8f1bbcdc;                // K_t
 185
 186         E = D;
 187         D = C;
 188         C = B << 30 | B >>> 2;         // S^30(B)
 189         B = A;
 190         A = TEMP;
 191       }
 192
 193     for (int t = 60; t < 80; ++ t)
 194       {
 195         int TEMP = (A << 5 | A >>> 27) // S^5(A)
 196           + (B ^ C ^ D)                // f_t(B,C,D)
 197           + E + W[t]
 198           + 0xca62c1d6;                // K_t
 199
 200         E = D;
 201         D = C;
 202         C = B << 30 | B >>> 2;         // S^30(B)
 203         B = A;
 204         A = TEMP;
 205       }
 206
 207     H0 += A;
 208     H1 += B;
 209     H2 += C;
 210     H3 += D;
 211     H4 += E;
 212
 213     // Reset W by clearing it.
 214     for (int t = 0; t < 80; ++ t)
 215       W[t] = 0;
 216   }
 217
 218   public Object clone ()
 219   {
 220     return new SHA (this);
 221   }
 222
 223   private SHA (SHA copy)
 224   {
 225     this ();
 226     bytecount = copy.bytecount;
 227     H0 = copy.H0;
 228     H1 = copy.H1;
 229     H2 = copy.H2;
 230     H3 = copy.H3;
 231     H4 = copy.H4;
 232     System.arraycopy (copy.W, 0, W, 0, 80);
 233   }
 234
 235   private final int W[] = new int[80];
 236   private long bytecount;
 237   private int H0;
 238   private int H1;
 239   private int H2;
 240   private int H3;
 241   private int H4;
 242 }