/* des: duplicate the NBS Data Encryption Standard in software.
* usage: des <file>
* prompts for the password
* If the filename ends in ".n" it will be decrypted with the key;
* otherwise it will be encrypted.
*
* Permutation algorithm:
* The permutation is defined by its effect on each of the 16 nibbles
* of the 64-bit input. For each nibble we give an 8-byte bit array
* that has the bits in the input nibble distributed correctly. The
* complete permutation involves ORing the 16 sets of 8 bytes designated
* by the 16 input nibbles. Uses 16*16*8 = 2K bytes of storage for
* each 64-bit permutation. 32-bit permutations (P) and expansion (E)
* are done similarly, but using bytes instead of nibbles.
* Should be able to use long ints, adding the masks, at a
* later pass. Tradeoff: can speed 64-bit perms up at cost of slowing
* down expansion or contraction operations by using 8K tables here and
* decreasing the size of the other tables.
* The compressions are pre-computed in 12-bit chunks, combining 2 of the
* 6->4 bit compressions.
* The key schedule is also precomputed.
* Compile with VALIDATE defined to run the NBS validation suite.
*
* Jim Gillogly, May 1977
* Modified 8/84 by Jim Gillogly and Lauren Weinstein to compile with
* post-1977 C compilers and systems
*
* This program is now officially in the public domain, and is available for
* any non-profit use as long as the authorship line is retained.
*/
/*#define VALIDATE */ /* define to check the NBS validation suite */
/*#define DEBUG */
/*#define LATTICE */ /* define for Lattice C on IBM PC */
#include <stdio.h>
#ifndef LATTICE
#include <sgtty.h>
#include <signal.h>
#include <sys/types.h> /* for local timer */
#include <sys/timeb.h> /* ditto */
struct sgttyb ttybuf; /* for gtty/stty */
int bye(); /* for caught interrupts */
#endif
char iperm[16][16][8],fperm[16][16][8]; /* inital and final permutations*/
char s[4][4096]; /* S1 thru S8 precomputed */
char p32[4][256][4]; /* for permuting 32-bit f output*/
char kn[16][6]; /* key selections */
endes(inblock,outblock) /* encrypt 64-bit inblock */
char *inblock, *outblock;
{ char iters[17][8]; /* workspace for each iteration */
char swap[8]; /* place to interchange L and R */
register int i;
register char *s, *t;
permute(inblock,iperm,iters[0]);/* apply initial permutation */
for (i=0; i<16; i++) /* 16 churning operations */
iter(i,iters[i],iters[i+1]);
/* don't re-copy to save space */
s = swap; t = &iters[16][4]; /* interchange left */
*s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++;
t = &iters[16][0]; /* and right */
*s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++;
permute(swap,fperm,outblock); /* apply final permutation */
}
dedes(inblock,outblock) /* decrypt 64-bit inblock */
char *inblock,*outblock;
{ char iters[17][8]; /* workspace for each iteration */
char swap[8]; /* place to interchange L and R */
register int i;
register char *s, *t;
permute(inblock,iperm,iters[0]);/* apply initial permutation */
for (i=0; i<16; i++) /* 16 churning operations */
iter(15-i,iters[i],iters[i+1]);
/* reverse order from encrypting*/
s = swap; t = &iters[16][4]; /* interchange left */
*s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++;
t = &iters[16][0]; /* and right */
*s++ = *t++; *s++ = *t++; *s++ = *t++; *s++ = *t++;
permute(swap,fperm,outblock); /* apply final permutation */
}
permute(inblock,perm,outblock) /* permute inblock with perm */
char *inblock, *outblock; /* result into outblock,64 bits */
char perm[16][16][8]; /* 2K bytes defining perm. */
{ register int i,j;
register char *ib, *ob; /* ptr to input or output block */
register char *p, *q;
for (i=0, ob = outblock; i<8; i++)
*ob++ = 0; /* clear output block */
ib = inblock;
for (j = 0; j < 16; j += 2, ib++) /* for each input nibble */
{ ob = outblock;
p = perm[j][(*ib >> 4) & 017];
q = perm[j + 1][*ib & 017];
for (i = 0; i < 8; i++) /* and each output byte */
*ob++ |= *p++ | *q++; /* OR the masks together*/
}
}
char ip[] /* initial permutation P */
= { 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 };
char fp[] /* final permutation F */
= { 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 };
/* expansion operation matrix */ /* rwo: unused */
/* char ei[] = { 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 }; */
char pc1[] /* permuted choice table (key) */
= { 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,
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 };
char totrot[] /* number left rotations of pc1 */
= { 1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28 };
char pc1m[56]; /* place to modify pc1 into */
char pcr[56]; /* place to rotate pc1 into */
char pc2[] /* permuted choice key (table) */
= { 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 };
char si[8][64] /* 48->32 bit compression tables*/
= { /* S[1] */
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,
/* S[2] */
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,
/* S[3] */
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,
/* S[4] */
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,
/* S[5] */
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,
/* S[6] */
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,
/* S[7] */
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,
/* S[8] */
13, 2, 8, 4, 6, 15
