freebsd-src/usr.bin/enigma/enigma.c
Joerg Wunsch 5dc67cd725 Fix some of the more blatant bugs in the original code, provide a
BSD-able Makefile, add a man page (that also puts a bold warning about
the weakness of the encryption), and implement the -k option for
compatibility with other vendor's implementations.  (Unlike those
other vendors, we actually also document this option and its
problems.)

There are more violations of style(9) in it, like the not-use of
getopt(3), but it's not worth the while fixing all of this.
1998-10-30 18:24:54 +00:00

184 lines
3.3 KiB
C

/*
* "enigma.c" is in file cbw.tar from
* anonymous FTP host watmsg.waterloo.edu: pub/crypt/cbw.tar.Z
*
* A one-rotor machine designed along the lines of Enigma
* but considerably trivialized.
*
* A public-domain replacement for the UNIX "crypt" command.
*
* Upgraded to function properly on 64-bit machines.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define MINUSKVAR "CrYpTkEy"
#define ECHO 010
#define ROTORSZ 256
#define MASK 0377
char t1[ROTORSZ];
char t2[ROTORSZ];
char t3[ROTORSZ];
char deck[ROTORSZ];
char buf[13];
void shuffle(char *);
void
setup(pw)
char *pw;
{
int ic, i, k, temp, pf[2], pid;
unsigned random;
long seed;
strncpy(buf, pw, 8);
while (*pw)
*pw++ = '\0';
buf[8] = buf[0];
buf[9] = buf[1];
pipe(pf);
if ((pid=fork())==0) {
close(0);
close(1);
dup(pf[0]);
dup(pf[1]);
execlp("makekey", "-", 0);
execl("/usr/libexec/makekey", "-", 0); /* BSDI */
execl("/usr/lib/makekey", "-", 0);
execl("/usr/bin/makekey", "-", 0); /* IBM */
execl("/lib/makekey", "-", 0);
perror("makekey");
fprintf(stderr, "enigma: cannot execute 'makekey', aborting\n");
exit(1);
}
write(pf[1], buf, 10);
close(pf[1]);
i=wait((int *)NULL);
if (i<0) perror("enigma: wait");
if (i!=pid) {
fprintf(stderr, "enigma: expected pid %d, got pid %d\n", pid, i);
exit(1);
}
if ((i=read(pf[0], buf, 13)) != 13) {
fprintf(stderr, "enigma: cannot generate key, read %d\n",i);
exit(1);
}
seed = 123;
for (i=0; i<13; i++)
seed = seed*buf[i] + i;
for(i=0;i<ROTORSZ;i++) {
t1[i] = i;
deck[i] = i;
}
for(i=0;i<ROTORSZ;i++) {
seed = 5*seed + buf[i%13];
if( sizeof(long) > 4 ) {
/* Force seed to stay in 32-bit signed math */
if( seed & 0x80000000 )
seed = seed | (-1L & ~0xFFFFFFFFL);
else
seed &= 0x7FFFFFFF;
}
random = seed % 65521;
k = ROTORSZ-1 - i;
ic = (random&MASK)%(k+1);
random >>= 8;
temp = t1[k];
t1[k] = t1[ic];
t1[ic] = temp;
if(t3[k]!=0) continue;
ic = (random&MASK) % k;
while(t3[ic]!=0) ic = (ic+1) % k;
t3[k] = ic;
t3[ic] = k;
}
for(i=0;i<ROTORSZ;i++)
t2[t1[i]&MASK] = i;
}
int
main(argc, argv)
char *argv[];
{
register int i, n1, n2, nr1, nr2;
int secureflg = 0, kflag = 0;
char *cp;
if (argc > 1 && argv[1][0] == '-') {
if (argv[1][1] == 's') {
argc--;
argv++;
secureflg = 1;
} else if (argv[1][1] == 'k') {
argc--;
argv++;
kflag = 1;
}
}
if (kflag) {
if ((cp = getenv(MINUSKVAR)) == NULL) {
fprintf(stderr, "%s not set\n", MINUSKVAR);
exit(1);
}
setup(cp);
} else if (argc != 2) {
setup(getpass("Enter key:"));
}
else
setup(argv[1]);
n1 = 0;
n2 = 0;
nr2 = 0;
while((i=getchar()) != -1) {
if (secureflg) {
nr1 = deck[n1]&MASK;
nr2 = deck[nr1]&MASK;
} else {
nr1 = n1;
}
i = t2[(t3[(t1[(i+nr1)&MASK]+nr2)&MASK]-nr2)&MASK]-nr1;
putchar(i);
n1++;
if(n1==ROTORSZ) {
n1 = 0;
n2++;
if(n2==ROTORSZ) n2 = 0;
if (secureflg) {
shuffle(deck);
} else {
nr2 = n2;
}
}
}
return 0;
}
void
shuffle(deck)
char deck[];
{
int i, ic, k, temp;
unsigned random;
static long seed = 123;
for(i=0;i<ROTORSZ;i++) {
seed = 5*seed + buf[i%13];
random = seed % 65521;
k = ROTORSZ-1 - i;
ic = (random&MASK)%(k+1);
temp = deck[k];
deck[k] = deck[ic];
deck[ic] = temp;
}
}