C语言教程:DES加密算法的程序
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C语言程序设计 | 发表日期:2010-10-30 9:44:22
/* 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, 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 };
char p32i[] /* 32-bit permutation function */
= { 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 };
desinit(key) /* initialize all des arrays */
char *key;
{
#ifdef DEBUG
/*deb*/ printf("Initial perm init.\n");
#endif
perminit(iperm,ip); /* initial permutation */
#ifdef DEBUG
/*deb*/ printf("Final perm init.\n");
#endif
perminit(fperm,fp); /* final permutation */
#ifdef DEBUG
/*deb*/ printf("Key sched init.\n");
#endif
kinit(key); /* key schedule */
#ifdef DEBUG
/*deb*/ printf("Compression init.\n");
#endif
sinit(); /* compression functions */
#ifdef DEBUG
/*deb*/ printf("32-bit perm init.\n");
#endif
p32init(); /* 32-bit permutation in f */
#ifdef DEBUG
/*deb*/ printf("End init.\n");
#endif
}
int bytebit[] /* bit 0 is left-most in byte */
= { 0200,0100,040,020,010,04,02,01 };
int nibblebit[] = { 010,04,02,01 };
sinit() /* initialize s1-s8 arrays */
{ register int i,j;
for (i=0; i<4; i++) /* each 12-bit position */
for (j=0; j<4096; j++) /* each possible 12-bit value */
s[i][j]=(getcomp(i*2,j>>6)<<4) |
(017&getcomp(i*2+1,j&077));
/* store 2 compressions per char*/
}
getcomp(k,v) /* 1 compression value for sinit*/
int k,v;
{ register int i,j; /* correspond to i and j in FIPS*/
i=((v&040)>>4)|(v&1); /* first and last bits make row */
j=(v&037)>>1; /* middle 4 bits are column */
return (int) si[k][(i<<4)+j]; /* result is ith row, jth col */
}
kinit(key) /* initialize key schedule array*/
char *key; /* 64 bits (will use only 56) */
{ register int i,j,l;
int m;
for (j=0; j<56; j++) /* convert pc1 to bits of key */
{ l=pc1[j]-1; /* integer bit location */
m = l & 07; /* find bit */
pc1m[j]=(key[l>>3] & /* find which key byte l is in */
bytebit[m]) /* and which bit of that byte */
? 1 : 0; /* and store 1-bit result */
}
for (i=0; i<16; i++) /* for each key sched section */
for (j=0; j<6; j++) /* and each byte of the kn */
kn[i][j]=0; /* clear it for accumulation */
for (i=0; i<16; i++) /* key chunk for each iteration */
{ for (j=0; j<56; j++) /* rotate pc1 the right amount */
pcr[j] = pc1m[(l=j+totrot[i])<(j<28? 28 : 56) ? l: l-28];
/* rotate left and right halves independently */
for (j=0; j<48; j++) /* select bits individually */
if (pcr[pc2[j]-1]) /* check bit that goes to kn[j] */
{ l= j & 07;
kn[i][j>>3] |= bytebit[l];
} /* mask it in if it's there */
}
}
p32init() /* initialize 32-bit permutation*/
{ register int l, j, k;
int i,m;
for (i=0; i<4; i++) /* each input byte position */
for (j=0; j<256; j++) /* all possible input bytes */
for (k=0; k<4; k++) /* each byte of the mask */
p32[i][j][k]=0; /* clear permutation array */
for (i=0; i<4; i++) /* each input byte position */
for (j=0; j<256; j++) /* each possible input byte */
for (k=0; k<32; k++) /* each output bit position */
{ l=p32i[k]-1; /* invert this bit (0-31) */
if ((l>>3)!=i) /* does it come from input posn?*/
continue; /* if not, bit k is 0 */
if (!(j&bytebit[l&07]))
continue; /* any such bit in input? */
m = k & 07; /* which bit is it? */
p32[i][j][k>>3] |= bytebit[m];
}
}
perminit(perm,p) /* initialize a perm array */
char perm[16][16][8]; /* 64-bit, either init or final */
char p[64];
{ register int l, j, k;
int i,m;
for (i=0; i<16; i++) /* each input nibble position */
for (j=0; j<16; j++) /* all possible input nibbles */
for (k=0; k<8; k++) /* each byte of the mask */
perm[i][j][k]=0;/* clear permutation array */
for (i=0; i<16; i++) /* each input nibble position */
for (j = 0; j < 16; j++)/* each possible input nibble */
for (k = 0; k < 64; k++)/* each output bit position */
{ l = p[k] - 1; /* where does this bit come from*/
if ((l >> 2) != i) /* does it come from input posn?*/
continue; /* if not, bit k is 0 */
if (!(j & nibblebit[l & 3]))
continue; /* any such bit in input? */
m = k & 07; /* which bit is this in the byte*/
perm[i][j][k>>3] |= bytebit[m];
}
}
iter(num,inblock,outblock) /* 1 churning operation */
int num; /* i.e. the num-th one */
char *inblock, *outblock; /* 64 bits each */
{ char fret[4]; /* return from f(R[i-1],key) */
register char *ib, *ob, *fb;
/* register int i; */ /* rwo: unused */
ob = outblock; ib = &inblock[4];
f(ib, num, fret); /* the primary transformation */
*ob++ = *ib++; /* L[i] = R[i-1] */
*ob++ = *ib++;
*ob++ = *ib++;
*ob++ = *ib++;
ib = inblock; fb = fret; /* R[i]=L[i] XOR f(R[i-1],key) */
*ob++ = *ib++ ^ *fb++;
*ob++ = *ib++ ^ *fb++;
*ob++ = *ib++ ^ *fb++;
*ob++ = *ib++ ^ *fb++;
}
f(right,num,fret) /* critical cryptographic trans */
char *right, *fret; /* 32 bits each */
int num; /* index number of this iter */
{ register char *kb, *rb, *bb; /* ptr to key selection &c */
char bigright[6]; /* right expanded to 48 bits */
char result[6]; /* expand(R) XOR keyselect[num] */
char preout[4]; /* result of 32-bit permutation */
kb = kn[num]; /* fast version of iteration */
bb = bigright;
rb = result;
expand(right,bb); /* expand to 48 bits */
*rb++ = *bb++ ^ *kb++; /* expanded R XOR chunk of key */
*rb++ = *bb++ ^ *kb++;
*rb++ = *bb++ ^ *kb++;
*rb++ = *bb++ ^ *kb++;
*rb++ = *bb++ ^ *kb++;
*rb++ = *bb++ ^ *kb++;
contract(result,preout); /* use S fns to get 32 bits */
perm32(preout,fret); /* and do final 32-bit perm */
}
perm32(inblock,outblock) /* 32-bit permutation at end */
char *inblock,*outblock; /* of the f crypto function */
{ register int j;
/* register int i; */ /* rwo: unused */
register char *ib, *ob;
register char *q;
ob = outblock; /* clear output block */
*ob++ = 0; *ob++ = 0; *ob++ = 0; *ob++ = 0;
ib=inblock; /* ptr to 1st byte of input */
for (j=0; j<4; j++, ib++) /* for each input byte */
{ q = p32[j][*ib & 0377];
ob = outblock; /* and each output byte */
*ob++ |= *q++; /* OR the 16 masks together */
*ob++ |= *q++;
*ob++ |= *q++;
*ob++ |= *q++;
}
}
expand(right,bigright) /* 32 to 48 bits with E oper */
char *right,*bigright; /* right is 32, bigright 48 */
{
register char *bb, *r, r0, r1, r2, r3;
bb = bigright;
r = right; r0 = *r++; r1 = *r++; r2 = *r++; r3 = *r++;
*bb++ = ((r3 & 0001) << 7) | /* 32 */
((r0 & 0370) >> 1) | /* 1 2 3 4 5 */
((r0 & 0030) >> 3); /* 4 5 */
*bb++ = ((r0 & 0007) << 5) | /* 6 7 8 */
((r1 & 0200) >> 3) | /* 9 */
((r0 & 0001) << 3) | /* 8 */
((r1 & 0340) >> 5); /* 9 10 11 */
*bb++ = ((r1 & 0030) << 3) | /* 12 13 */
((r1 & 0037) << 1) | /* 12 13 14 15 16 */
((r2 & 0200) >> 7); /* 17 */
*bb++ = ((r1 & 0001) << 7) | /* 16 */
((r2 & 0370) >> 1) | /* 17 18 19 20 21 */
((r2 & 0030) >> 3); /* 20 21 */
*bb++ = ((r2 & 0007) << 5) | /* 22 23 24 */
((r3 & 0200) >> 3) | /* 25 */
((r2 & 0001) << 3) | /* 24 */
((r3 & 0340) >> 5); /* 25 26 27 */
*bb++ = ((r3 & 0030) << 3) | /* 28 29 */
((r3 & 0037) << 1) | /* 28 29 30 31 32 */
((r0 & 0200) >> 7); /* 1 */
}
contract(in48,out32) /* contract f from 48 to 32 bits*/
char *in48,*out32; /* using 12-bit pieces into bytes */
{ register char *c;
register char *i;
register int i0, i1, i2, i3, i4, i5;
i = in48;
i0 = *i++; i1 = *i++; i2 = *i++; i3 = *i++; i4 = *i++; i5 = *i++;
c = out32; /* do output a byte at a time */
*c++ = s[0][07777 & ((i0 << 4) | ((i1 >> 4) & 017 ))];
*c++ = s[1][07777 & ((i1 << 8) | ( i2 & 0377 ))];
*c++ = s[2][07777 & ((i3 << 4) | ((i4 >> 4) & 017 ))];
*c++ = s[3][07777 & ((i4 << 8) | ( i5 & 0377 ))];
}
/* End of DES algorithm (except for calling desinit below) */
#ifndef VALIDATE
char *inname, *outname;
FILE *infile, *outfile;
int encrypting;
char buf[512];
char keyx[9], keyy[9];
char *malloc(), *strcpy(), *strcat();
main(argc, argv)
int argc; char *argv[];
{ register char *u;
char *filename;
if (argc < 2) /* filenames given? */
{ fprintf(stderr, "Usage: des file ...\n");
exit(1);
}
for (++argv; --argc; ++argv)
{ inname = *argv;
outname = filename = malloc((unsigned) strlen(inname) + 3);
strcpy(filename, inname);
u = &filename[strlen(filename) - 2]; /* check last 2 chars */
encrypting = (strcmp(".n", u) != 0);
if (!encrypting) *u = 0; /* strip .n from output filename */
else strcat(filename, ".n"); /* or add .n to output file */
if ((infile = fopen(inname, "rb")) == NULL)
{ fprintf(stderr,"Can't read %s.\n", inname);
exit(1);
}
if ((outfile = fopen(outname, "rb")) != NULL)
{ fprintf(stderr, "%s would be overwritten.\n",outname);
exit(1);
}
if ((outfile = fopen(outname, "wb")) == NULL)
{ fprintf(stderr,"Can't write %s.\n", outname);
exit(1);
}
key_get("Type password for ");
for (;;)
{ strcpy(keyx, keyy);
key_get("Verify password for ");
if (strcmp(keyx, keyy) == 0) break;
}
desinit(keyx); /* set up tables for DES */
if (pfile() == 0) unlink(inname);
else fprintf(stderr,
"%s: I/O Error -- File unchanged\n", inname);
fclose(outfile);
fclose(infile);
}
exit(0);
}
key_get(mes) /* get file key */
char *mes;
{ register int i, j;
char linebuf[256];
int count;
for (i=0; i<14; i++) keyy[i]=0;
#ifdef LATTICE
#else
gtty(0, &ttybuf);
ttybuf.sg_flags &= ~ECHO; /* turn off echoing */
signal(SIGINT, bye); /* catch ints */
stty(0, &ttybuf);
#endif
printf("%s%s: ", mes, inname);
fflush(stdout);
count = read(0, linebuf, 256); /* read input line */
printf("\n");
#ifndef LATTICE
ttybuf.sg_flags |= ECHO; /* restore echo */
stty(0, &ttybuf);
#endif
linebuf[count] = 0; /* null terminate */
if (linebuf[count-1] == '\n') /* ignore any terminating newline */
{ linebuf[count-1] = 0;
count--;
}
if (count > 8) count = 8; /* only use 8 chars */
for (i = j = 0; count--;)
keyy[i++] = linebuf[j++];
}
pfile() /* process the file */
{ register int m, nsave;
register char *b;
int j;
while (m = fread(buf, 1, 512, infile))
{
if ((nsave = m) < 0) /* read error */
return(-1);
for (b=buf; m>0; /* encrypt/decrypt 1 buffer-full*/
m -= 8, b += 8) /* 8-byte blocks */
{ if (encrypting)
{ if (m<8) /* don't have a full 64 bits */
{ for (j=0; j<8-m; j++)
b[m+j]=garbage(); /* fill block with trash */
nsave += 8-m; /* complete the block */
}
else j=0 /* number of nulls in last block*/
endes(b,b); /* don't need diff input, output*/
}
else /* decrypting */
{ if (m < 8) deout(b, 1); /* last byte in file: count */
else
{ dedes(b, b); /* decrypt and output block */
deout(b, 0);
}
}
}
if (encrypting) if (fwrite(buf, 1, nsave, outfile) != nsave)
return(-1);
}
/* have now encrypted/decrypted the whole file;
* need to append the byte count for the last block if encrypting.
*/
if (encrypting) fputc(8 - j, outfile); /* how many good bytes? */
return(0);
}
int outcount = 0; /* see when caught up with delay*/
deout(block,flag) /* 1-block delay on output */
char *block,flag; /* 64-bit block, last block flag*/
{ static char last[8]; /* previous input block */
register int i;
/* register char *c,*j; */ /* rwo: unused */
if (flag) /* output the last few bytes */
{
fwrite(last, 1, block[0] & 0377, outfile);
return;
}
if (outcount++) /* seen any blocks before? */
fwrite(last, 1, 8, outfile);
for (i = 0; i < 8; i++) last[i] = block[i]; /* copy the block */
}
garbage() /* generate garbage for filling */
/* This garbage should be as random as possible. We're using subsequent calls
* on the timer, but ideally each byte should be uncorrelated. Preferable
* would be to call the timer once and use it to initialize a dumb random
* number generator.
*/
{
#ifdef LATTICE
long timer(), ltime;
ltime = timer();
return (int) ltime & 0377;
#else
struct timeb tp;
ftime(&tp); /* get current time */
return tp.millitm; /* return time in milliseconds */
#endif
}
#ifndef LATTICE
/* restore echo to tty and exit */
bye()
{
ttybuf.sg_flags |= ECHO; /* restore echoing */
stty(0, &ttybuf);
exit(2);
}
#endif
#else /* validation */
#define VALFILE "valid.triples"
FILE *fd;
char key[8], plain[8], cipher[8], processed[8];
main() /* read key/plain/cipher triples until exhausted */
{ int count, i;
if ((fd = fopen(VALFILE, "r")) == NULL)
{ fprintf(stderr, "Can't read %s.\n", VALFILE);
exit(1);
}
count = 0;
desinit(key); /* initialize most of the arrays */
while (readvals())
{ kinit(key); /* initialize key stuff */
printf("Key: "); writehex(key);
printf(" Plain: "); writehex(plain);
printf(" Cipher: "); writehex(cipher);
printf("\n");
endes(plain, processed); /* encipher the plaintext */
printf("Encry: "); writehex(processed);
printf("\n");
for (i = 0; i < 8; i++)
if (processed[i] != cipher[i])
printf("Encryption failed.\n");
dedes(cipher, processed); /* decipher the ciphertext */
printf("Decry: "); writehex(processed);
printf("\n");
for (i = 0; i < 8; i++)
if (processed[i] != plain[i])
printf("Decryption failed.\n");
count++;
}
printf("Processed %d tests.\n", count);
}
readvals() /* get the next legit triple */
{ int r;
r = readhex(key);
readhex(plain);
readhex(cipher);
return r;
}
writehex(str) /* write the 64-bit hex string */
char *str;
{ int i;
for (i = 0; i < 8; i++)
printf("%02x", str[i] & 0377);
}
hex(n) /* convert hex nibble into integer */
int n;
{
if (n >= 'A' && n <= 'F') return n - 'A' + 10;
return n - '0';
}
readhex(str) /* read 64 bits of hex code */
char *str;
{ int i, c;
for (i = 0; i < 8; i++)
{ c = hex(getc(fd)) << 4;
str[i] = c | hex(getc(fd));
}
while ((c = getc(fd)) == ' ' || c == '\t' || c == '\n');
ungetc(c, fd); /* skip to next field */
return c != EOF;
}
#endif
/************ end scrydes ************/
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