openssl中des实现过程问题

Question

在openssl实现des加密过程中在setkey函数用到了一个des_skb[8][64]矩阵，这是个什么矩阵？怎么在des原理中没有提到这个矩阵？附上setkey函数和des_skb矩阵：

static const DES_LONG des_skb[8][64]={
 {
 /* for C bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
 0x00000000L,0x00000010L,0x20000000L,0x20000010L,
 0x00010000L,0x00010010L,0x20010000L,0x20010010L,
 0x00000800L,0x00000810L,0x20000800L,0x20000810L,
 0x00010800L,0x00010810L,0x20010800L,0x20010810L,
 0x00000020L,0x00000030L,0x20000020L,0x20000030L,
 0x00010020L,0x00010030L,0x20010020L,0x20010030L,
 0x00000820L,0x00000830L,0x20000820L,0x20000830L,
 0x00010820L,0x00010830L,0x20010820L,0x20010830L,
 0x00080000L,0x00080010L,0x20080000L,0x20080010L,
 0x00090000L,0x00090010L,0x20090000L,0x20090010L,
 0x00080800L,0x00080810L,0x20080800L,0x20080810L,
 0x00090800L,0x00090810L,0x20090800L,0x20090810L,
 0x00080020L,0x00080030L,0x20080020L,0x20080030L,
 0x00090020L,0x00090030L,0x20090020L,0x20090030L,
 0x00080820L,0x00080830L,0x20080820L,0x20080830L,
 0x00090820L,0x00090830L,0x20090820L,0x20090830L,
 },{
 /* for C bits (numbered as per FIPS 46) 7 8 10 11 12 13 */
 0x00000000L,0x02000000L,0x00002000L,0x02002000L,
 0x00200000L,0x02200000L,0x00202000L,0x02202000L,
 0x00000004L,0x02000004L,0x00002004L,0x02002004L,
 0x00200004L,0x02200004L,0x00202004L,0x02202004L,
 0x00000400L,0x02000400L,0x00002400L,0x02002400L,
 0x00200400L,0x02200400L,0x00202400L,0x02202400L,
 0x00000404L,0x02000404L,0x00002404L,0x02002404L,
 0x00200404L,0x02200404L,0x00202404L,0x02202404L,
 0x10000000L,0x12000000L,0x10002000L,0x12002000L,
 0x10200000L,0x12200000L,0x10202000L,0x12202000L,
 0x10000004L,0x12000004L,0x10002004L,0x12002004L,
 0x10200004L,0x12200004L,0x10202004L,0x12202004L,
 0x10000400L,0x12000400L,0x10002400L,0x12002400L,
 0x10200400L,0x12200400L,0x10202400L,0x12202400L,
 0x10000404L,0x12000404L,0x10002404L,0x12002404L,
 0x10200404L,0x12200404L,0x10202404L,0x12202404L,
 },{
 /* for C bits (numbered as per FIPS 46) 14 15 16 17 19 20 */
 0x00000000L,0x00000001L,0x00040000L,0x00040001L,
 0x01000000L,0x01000001L,0x01040000L,0x01040001L,
 0x00000002L,0x00000003L,0x00040002L,0x00040003L,
 0x01000002L,0x01000003L,0x01040002L,0x01040003L,
 0x00000200L,0x00000201L,0x00040200L,0x00040201L,
 0x01000200L,0x01000201L,0x01040200L,0x01040201L,
 0x00000202L,0x00000203L,0x00040202L,0x00040203L,
 0x01000202L,0x01000203L,0x01040202L,0x01040203L,
 0x08000000L,0x08000001L,0x08040000L,0x08040001L,
 0x09000000L,0x09000001L,0x09040000L,0x09040001L,
 0x08000002L,0x08000003L,0x08040002L,0x08040003L,
 0x09000002L,0x09000003L,0x09040002L,0x09040003L,
 0x08000200L,0x08000201L,0x08040200L,0x08040201L,
 0x09000200L,0x09000201L,0x09040200L,0x09040201L,
 0x08000202L,0x08000203L,0x08040202L,0x08040203L,
 0x09000202L,0x09000203L,0x09040202L,0x09040203L,
 },{
 /* for C bits (numbered as per FIPS 46) 21 23 24 26 27 28 */
 0x00000000L,0x00100000L,0x00000100L,0x00100100L,
 0x00000008L,0x00100008L,0x00000108L,0x00100108L,
 0x00001000L,0x00101000L,0x00001100L,0x00101100L,
 0x00001008L,0x00101008L,0x00001108L,0x00101108L,
 0x04000000L,0x04100000L,0x04000100L,0x04100100L,
 0x04000008L,0x04100008L,0x04000108L,0x04100108L,
 0x04001000L,0x04101000L,0x04001100L,0x04101100L,
 0x04001008L,0x04101008L,0x04001108L,0x04101108L,
 0x00020000L,0x00120000L,0x00020100L,0x00120100L,
 0x00020008L,0x00120008L,0x00020108L,0x00120108L,
 0x00021000L,0x00121000L,0x00021100L,0x00121100L,
 0x00021008L,0x00121008L,0x00021108L,0x00121108L,
 0x04020000L,0x04120000L,0x04020100L,0x04120100L,
 0x04020008L,0x04120008L,0x04020108L,0x04120108L,
 0x04021000L,0x04121000L,0x04021100L,0x04121100L,
 0x04021008L,0x04121008L,0x04021108L,0x04121108L,
 },{
 /* for D bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
 0x00000000L,0x10000000L,0x00010000L,0x10010000L,
 0x00000004L,0x10000004L,0x00010004L,0x10010004L,
 0x20000000L,0x30000000L,0x20010000L,0x30010000L,
 0x20000004L,0x30000004L,0x20010004L,0x30010004L,
 0x00100000L,0x10100000L,0x00110000L,0x10110000L,
 0x00100004L,0x10100004L,0x00110004L,0x10110004L,
 0x20100000L,0x30100000L,0x20110000L,0x30110000L,
 0x20100004L,0x30100004L,0x20110004L,0x30110004L,
 0x00001000L,0x10001000L,0x00011000L,0x10011000L,
 0x00001004L,0x10001004L,0x00011004L,0x10011004L,
 0x20001000L,0x30001000L,0x20011000L,0x30011000L,
 0x20001004L,0x30001004L,0x20011004L,0x30011004L,
 0x00101000L,0x10101000L,0x00111000L,0x10111000L,
 0x00101004L,0x10101004L,0x00111004L,0x10111004L,
 0x20101000L,0x30101000L,0x20111000L,0x30111000L,
 0x20101004L,0x30101004L,0x20111004L,0x30111004L,
 },{
 /* for D bits (numbered as per FIPS 46) 8 9 11 12 13 14 */
 0x00000000L,0x08000000L,0x00000008L,0x08000008L,
 0x00000400L,0x08000400L,0x00000408L,0x08000408L,
 0x00020000L,0x08020000L,0x00020008L,0x08020008L,
 0x00020400L,0x08020400L,0x00020408L,0x08020408L,
 0x00000001L,0x08000001L,0x00000009L,0x08000009L,
 0x00000401L,0x08000401L,0x00000409L,0x08000409L,
 0x00020001L,0x08020001L,0x00020009L,0x08020009L,
 0x00020401L,0x08020401L,0x00020409L,0x08020409L,
 0x02000000L,0x0A000000L,0x02000008L,0x0A000008L,
 0x02000400L,0x0A000400L,0x02000408L,0x0A000408L,
 0x02020000L,0x0A020000L,0x02020008L,0x0A020008L,
 0x02020400L,0x0A020400L,0x02020408L,0x0A020408L,
 0x02000001L,0x0A000001L,0x02000009L,0x0A000009L,
 0x02000401L,0x0A000401L,0x02000409L,0x0A000409L,
 0x02020001L,0x0A020001L,0x02020009L,0x0A020009L,
 0x02020401L,0x0A020401L,0x02020409L,0x0A020409L,
 },{
 /* for D bits (numbered as per FIPS 46) 16 17 18 19 20 21 */
 0x00000000L,0x00000100L,0x00080000L,0x00080100L,
 0x01000000L,0x01000100L,0x01080000L,0x01080100L,
 0x00000010L,0x00000110L,0x00080010L,0x00080110L,
 0x01000010L,0x01000110L,0x01080010L,0x01080110L,
 0x00200000L,0x00200100L,0x00280000L,0x00280100L,
 0x01200000L,0x01200100L,0x01280000L,0x01280100L,
 0x00200010L,0x00200110L,0x00280010L,0x00280110L,
 0x01200010L,0x01200110L,0x01280010L,0x01280110L,
 0x00000200L,0x00000300L,0x00080200L,0x00080300L,
 0x01000200L,0x01000300L,0x01080200L,0x01080300L,
 0x00000210L,0x00000310L,0x00080210L,0x00080310L,
 0x01000210L,0x01000310L,0x01080210L,0x01080310L,
 0x00200200L,0x00200300L,0x00280200L,0x00280300L,
 0x01200200L,0x01200300L,0x01280200L,0x01280300L,
 0x00200210L,0x00200310L,0x00280210L,0x00280310L,
 0x01200210L,0x01200310L,0x01280210L,0x01280310L,
 },{
 /* for D bits (numbered as per FIPS 46) 22 23 24 25 27 28 */
 0x00000000L,0x04000000L,0x00040000L,0x04040000L,
 0x00000002L,0x04000002L,0x00040002L,0x04040002L,
 0x00002000L,0x04002000L,0x00042000L,0x04042000L,
 0x00002002L,0x04002002L,0x00042002L,0x04042002L,
 0x00000020L,0x04000020L,0x00040020L,0x04040020L,
 0x00000022L,0x04000022L,0x00040022L,0x04040022L,
 0x00002020L,0x04002020L,0x00042020L,0x04042020L,
 0x00002022L,0x04002022L,0x00042022L,0x04042022L,
 0x00000800L,0x04000800L,0x00040800L,0x04040800L,
 0x00000802L,0x04000802L,0x00040802L,0x04040802L,
 0x00002800L,0x04002800L,0x00042800L,0x04042800L,
 0x00002802L,0x04002802L,0x00042802L,0x04042802L,
 0x00000820L,0x04000820L,0x00040820L,0x04040820L,
 0x00000822L,0x04000822L,0x00040822L,0x04040822L,
 0x00002820L,0x04002820L,0x00042820L,0x04042820L,
 0x00002822L,0x04002822L,0x00042822L,0x04042822L,
 }};

void DES_set_key_unchecked(const_DES_cblock *key, DES_key_schedule *schedule)
 {
 static int shifts2[16]={0,0,1,1,1,1,1,1,0,1,1,1,1,1,1,0};
 register DES_LONG c,d,t,s,t2;
 register const unsigned char *in;
 register DES_LONG *k;
 register int i;

#ifdef OPENBSD_DEV_CRYPTO
 memcpy(schedule->key,key,sizeof schedule->key);
 schedule->session=NULL;
#endif
 k = &schedule->ks->deslong[0];
 in = &(*key)[0];

 c2l(in,c);
 c2l(in,d);

 /* do PC1 in 47 simple operations :-)
  * Thanks to John Fletcher (john_fletcher@lccmail.ocf.llnl.gov)
  * for the inspiration. :-) */
 PERM_OP (d,c,t,4,0x0f0f0f0fL);
 HPERM_OP(c,t,-2,0xcccc0000L);
 HPERM_OP(d,t,-2,0xcccc0000L);
 PERM_OP (d,c,t,1,0x55555555L);
 PERM_OP (c,d,t,8,0x00ff00ffL);
 PERM_OP (d,c,t,1,0x55555555L);
 d= (((d&0x000000ffL)<<16L)| (d&0x0000ff00L)     |
   ((d&0x00ff0000L)>>16L)|((c&0xf0000000L)>>4L));
 c&=0x0fffffffL;

 for (i=0; i<ITERATIONS; i++)
  {
  if (shifts2[i])
   { c=((c>>2L)|(c<<26L)); d=((d>>2L)|(d<<26L)); }
  else
   { c=((c>>1L)|(c<<27L)); d=((d>>1L)|(d<<27L)); }
  c&=0x0fffffffL;
  d&=0x0fffffffL;
  /* could be a few less shifts but I am to lazy at this
   * point in time to investigate */
  s= des_skb[0][ (c    )&0x3f                ]|
   des_skb[1][((c>> 6L)&0x03)|((c>> 7L)&0x3c)]|
   des_skb[2][((c>>13L)&0x0f)|((c>>14L)&0x30)]|
   des_skb[3][((c>>20L)&0x01)|((c>>21L)&0x06) |
        ((c>>22L)&0x38)];
  t= des_skb[4][ (d    )&0x3f                ]|
   des_skb[5][((d>> 7L)&0x03)|((d>> 8L)&0x3c)]|
   des_skb[6][ (d>>15L)&0x3f                ]|
   des_skb[7][((d>>21L)&0x0f)|((d>>22L)&0x30)];

  /* table contained 0213 4657 */
  t2=((t<<16L)|(s&0x0000ffffL))&0xffffffffL;
  *(k++)=ROTATE(t2,30)&0xffffffffL;

  t2=((s>>16L)|(t&0xffff0000L));
  *(k++)=ROTATE(t2,26)&0xffffffffL;
  }
 }

Answer 1

感觉是密钥扩展置换。