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