des_encryption.java

DES加解密原码,包含DES算法的详细实现过程,并且添加了方法参数的详细说明

/*
 * 创建日期 2005-3-7
 *
 * TODO 要更改此生成的文件的模板，请转至
 * 窗口 － 首选项 － Java － 代码样式 － 代码模板
 */
package yzh_test.testFTS_NG.testClient;

/**
 * @author Administrator
 *
 * TODO 要更改此生成的类型注释的模板，请转至
 * 窗口 － 首选项 － Java － 代码样式 － 代码模板
 */

public class DES_Encryption {

 private static byte[][] C = new byte[17][28];
 private static byte[][] D = new byte[17][28];
 private static byte[][] K = new byte[17][48];

 private static int[] pc_1_c={
     57,49,41,33,25,17,9
     ,1,58,50,42,34,26,18
     ,10,2,59,51,43,35,27
     ,19,11,3,60,52,44,36};

 private static int[] pc_1_d={
     63,55,47,39,31,23,15
     ,7,62,54,46,38,30,22
     ,14,6,61,53,45,37,29
     ,21,13,5,28,20,12,4};

 private static int[] pc_2={
     14,17,11,24,1,5,
     3,28,15,6,21,10,
     23,19,12,4,26,8,
     16,7,27,20,13,2,
     41,52,31,37,47,55,
     30,40,51,45,33,48,
     44,49,39,56,34,53,
     46,42,50,36,29,32};

 private static int[] ls_count={
     1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};

 private static int[] ip_tab={
     58,50,42,34,26,18,10,2,
     60,52,44,36,28,20,12,4,
     62,54,46,38,30,22,14,6,
     64,56,48,40,32,24,16,8,
    57,49,41,33,25,17,9,1,
    59,51,43,35,27,19,11,3,
    61,53,45,37,29,21,13,5,
    63,55,47,39,31,23,15,7};

 private static int[] _ip_tab={
     40,8,48,16,56,24,64,32,
     39,7,47,15,55,23,63,31,
     38,6,46,14,54,22,62,30,
     37,5,45,13,53,21,61,29,
     36,4,44,12,52,20,60,28,
     35,3,43,11,51,19,59,27,
     34,2,42,10,50,18,58,26,
     33,1,41,9,49,17,57,25};

 private static int[] e_r={
     32,1,2,3,4,5,4,5,6,7,8,9,
     8,9,10,11,12,13,12,13,14,15,16,17,
     16,17,18,19,20,21,20,21,22,23,24,25,
     24,25,26,27,28,29,28,29,30,31,32,1};

 private static int[] P={
     16,7,20,21,29,12,28,17,
     1,15,23,26,5,18,31,10,
     2,8,24,14,32,27,3,9,
     19,13,30,6,22,11,4,25};

 private static int SSS[][][]={
  {{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
      {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
      {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
      {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}},

  {{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
      {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
      {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
      {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}},

  {{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
      {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
      {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
      {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}},

  {{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
      {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
      {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
      {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}},

  {{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
      {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
      {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
      {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}},

  {{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
      {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
      {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
      {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}},

  {{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
      {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
      {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
      {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}},

  {{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
      {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
      {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
   {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}}};

    public static byte[] EncryptMessage(byte[] InputMessage, byte[] Keybyte, int len, int offset)
    {
     DES(InputMessage, Keybyte, len, offset);
     return InputMessage;
    }

    public static byte[] DecryptMessage(byte[] InputMessage, byte[] Keybyte, int len, int offset)
    {
     UNDES(InputMessage, Keybyte, len, offset);
     return InputMessage;
    }

 public static void DES(byte[] buf, byte[] deskey, int len, int offset)
 {
  byte[] ptr = new byte[8];
  byte[] stmp = new byte[8];
  for(int i = 0; i < (len - offset) / 8; i++)
   {
     System.arraycopy(buf, offset + 8 * i, ptr, 0, 8);
     des(ptr, deskey, stmp);
     System.arraycopy(stmp, 0, buf, offset + 8 * i, 8);
   }
 }
//UNDES(msg,"11111111".getbytes,msg.length,6);
//byte[] buf:待解密的数组
//byte[] deskey:密钥
//int len:待解密的数组的长度
//int offset:数组的偏移量
 public static void UNDES(byte[] buf, byte[] deskey, int len, int offset)
 {
  byte[] ptr = new byte[8];
  byte[] stmp = new byte[8];
  int times = (len - offset) / 8;
  for(int i = 0; i < times; i++)
   { System.arraycopy(buf, offset + 8 * i, ptr, 0, 8);
     undes(ptr, deskey,stmp);
     System.arraycopy(stmp, 0, buf, offset + 8 * i, 8);
  }
 }

 private static void expand0(byte[] in, byte[] out)
 {
  for(int i = 0; i < 8; i++)
  {  int in_tmp = in[i];
   if(in_tmp < 0) {
      in_tmp += 0x100; }
   int divide = 0x80;
   for(int j = 0; j < 8; j++)
     { out[8 * i + j] = (byte)((in_tmp / divide) & 1);
       divide /= 2;
     }
  }
 }

 private static void ip(byte[] text, byte[] ll, byte[] rr)
 {
  byte[] buffer = new byte[64];
  expand0(text, buffer);

  for(int i = 0; i < 32; i++) {
   ll[i] = buffer[ip_tab[i] - 1]; }
  for(int i = 0; i < 32; i++) {
   rr[i] = buffer[ip_tab[i + 32] - 1]; }
 }

 private static void _ip(byte[] text, byte[] ll, byte[] rr)
 {
  byte[] tmp = new byte[64];
  System.arraycopy(ll, 0, tmp, 0, 32);
  System.arraycopy(rr, 0, tmp, 32, 32);
  for(int i = 0; i < 64; i++)
  {
   text[i]=tmp[_ip_tab[i] - 1];
  }
 }

 private static void s_box(byte[] aa, byte[] bb)
 {
  int j;
  int y;
  int z;
  int m = 0;
  byte[] ss = new byte[8];
  for(int i = 0; i < 8; i++)
  {
   j = 6 * i;
   y = aa[j] * 2 + aa[j + 5];
   z = aa[j + 1] * 8 + aa[j + 2] * 4 + aa[j + 3] * 2 + aa[j + 4];
   ss[i] = (byte)SSS[i][y][z];
   y = 0x08;
         for (int k = 0; k < 4; k++)
         {  bb[m++] = (byte)((ss[i] / y) & 1);
            y /= 2;
         }
     }
 }

 private static void F(int n, byte[] ll, byte[] rr, byte[] LL, byte[] RR)
 {
  byte[] buffer = new byte[48];
  byte[] tmp = new byte[48];
  int i;
     for (i = 0; i < 48; i++) {
         buffer[i] = rr[e_r[i] - 1]; }
     for (i = 0; i < 48; i++) {
         buffer[i] = (byte)((buffer[i] + K[n][i]) & 1); }
     s_box(buffer, tmp);
     for (i = 0; i < 32; i++) {
         buffer[i] = tmp[P[i] - 1]; }
     for (i = 0; i < 32; i++) {
         RR[i] = (byte)((buffer[i] + ll[i]) & 1); }
  for(i = 0; i < 32; i++) {
   LL[i] = rr[i]; }
 }

 private static void compress0(byte[] out, byte[] in)
 {
  for(int i = 0; i < 8; i++)
  {
   int times = 0x80;
   in[i] = 0;
   for(int j = 0; j < 8; j++)
   {
    in[i] += (byte)(out[8 * i + j] * times);
    times /= 2;
   }
  }
 }

 private static void encrypt0(byte[] text, byte[] mtext)
 {
  byte[] ll = new byte[64];
  byte[] rr = new byte[64];
  byte[] LL = new byte[64];
  byte[] RR = new byte[64];
  byte[] tmp = new byte[64];
  ip(text,ll,rr);
  for(int i = 1; i < 17; i++)
    {
     F(i,ll,rr,LL,RR);
       for (int j = 0; j < 32; j++)
         {   ll[j] = LL[j];
             rr[j] = RR[j];
         }
    }
     _ip(tmp, rr, ll);
     compress0(tmp, mtext);
 }

 private static void discrypt0(byte[] mtext, byte[] text)
 {
  byte[] ll = new byte[64];
  byte[] rr = new byte[64];
  byte[] LL = new byte[64];
  byte[] RR = new byte[64];
  byte[] tmp = new byte[64];
  ip(mtext,ll,rr);
     for (int i=16;i>0;i--)  {
       F(i,ll,rr,LL,RR);
         for (int j = 0; j < 32; j++)
           { ll[j] = LL[j];
             rr[j] = RR[j];
           }
    }
     _ip(tmp, rr, ll);
     compress0(tmp, text);
 }

 private static void son(byte[] cc, byte[] dd, byte[] kk)
 {
  byte[] buffer = new byte[56];
  int i;
  for(i = 0; i < 28; i++) {
   buffer[i] = cc[i]; }
  for(i = 28; i < 56; i++) {
     buffer[i] = dd[i - 28]; }
  for(i = 0; i < 48; i++) {
     kk[i] = buffer[pc_2[i] - 1]; }
 }

 public static void LS(byte[] bits, byte[] buffer, int count)
 {
     for (int i = 0; i < 28; i++)
     {
         buffer[i] = bits[(i + count) % 28];
     }
 }

 private static void setkeystar(byte[] bits)
 {
     for (int i = 0; i < 28; i++)
         C[0][i] = bits[pc_1_c[i] - 1];
     for (int i = 0; i < 28; i++)
         D[0][i] = bits[pc_1_d[i] - 1];
     for (int j=0;j<16;j++)
  {
   LS(C[j], C[j + 1], ls_count[j]);
   LS(D[j], D[j + 1], ls_count[j]);
   son(C[j + 1], D[j + 1], K[j + 1]);
     }
 }

 public static void des(byte[] text, byte[] key, byte[] mtext)
 {
  byte[] text_sav = new byte[8];
  byte[] tmp = new byte[64];
  System.arraycopy(text, 0, text_sav, 0, 8);
  expand0(key, tmp);
  setkeystar(tmp);
  encrypt0(text_sav, mtext);
 }

 public static void undes(byte[] text, byte[] key, byte[] mtext)
 {
  byte[] tmp = new byte[64];
  expand0(key, tmp);
  setkeystar(tmp);
  discrypt0(text,mtext);
 }
}