-/*
- * crblock: encrypt/decrypt a block of text.
- * buf is the buffer through which the text is both input and
- * output. nchar is the size of the buffer. permp is a work
- * buffer, and startn is the beginning of a sequence.
- */
-crblock(permp, buf, nchar, startn)
-char *permp;
-char *buf;
-int nchar;
-long startn;
-{
- register char *p1;
- int n1;
- int n2;
- register char *t1, *t2, *t3;
-
- t1 = permp;
- t2 = &permp[256];
- t3 = &permp[512];
-
- n1 = startn&0377;
- n2 = (startn>>8)&0377;
- p1 = buf;
- while(nchar--) {
- *p1 = t2[(t3[(t1[(*p1+n1)&0377]+n2)&0377]-n2)&0377]-n1;
- n1++;
- if(n1==256){
- n1 = 0;
- n2++;
- if(n2==256) n2 = 0;
- }
- p1++;
- }
-}
-
-/*
- * makekey: initialize buffers based on user key a.
- */
-makekey(a, b)
-char *a, *b;
-{
- register int i;
- long t;
- char temp[KSIZE + 1];
-
- for(i = 0; i < KSIZE; i++)
- temp[i] = *a++;
- time(&t);
- t += getpid();
- for(i = 0; i < 4; i++)
- temp[i] ^= (t>>(8*i))&0377;
- crinit(temp, b);
-}
-
-/*
- * crinit: besides initializing the encryption machine, this routine
- * returns 0 if the key is null, and 1 if it is non-null.
- */
-crinit(keyp, permp)
-char *keyp, *permp;
-{
- register char *t1, *t2, *t3;
- register i;
- int ic, k, temp;
- unsigned random;
- char buf[13];
- long seed;
-
- t1 = permp;
- t2 = &permp[256];
- t3 = &permp[512];
- if(*keyp == 0)
- return(0);
- strncpy(buf, keyp, 8);
- while (*keyp)
- *keyp++ = '\0';
-
- buf[8] = buf[0];
- buf[9] = buf[1];
- domakekey(buf);
-
- seed = 123;
- for (i=0; i<13; i++)
- seed = seed*buf[i] + i;
- for(i=0;i<256;i++){
- t1[i] = i;
- t3[i] = 0;
- }
- for(i=0; i<256; i++) {
- seed = 5*seed + buf[i%13];
- random = seed % 65521;
- k = 256-1 - i;
- ic = (random&0377) % (k+1);
- random >>= 8;
- temp = t1[k];
- t1[k] = t1[ic];
- t1[ic] = temp;
- if(t3[k]!=0) continue;
- ic = (random&0377) % k;
- while(t3[ic]!=0) ic = (ic+1) % k;
- t3[k] = ic;
- t3[ic] = k;
- }
- for(i=0; i<256; i++)
- t2[t1[i]&0377] = i;
- return(1);
-}
-
-/*
- * domakekey: the following is the major nonportable part of the encryption
- * mechanism. A 10 character key is supplied in buffer.
- * This string is fed to makekey (an external program) which
- * responds with a 13 character result. This result is placed
- * in buffer.
- */
-domakekey(buffer)
-char *buffer;
-{
- int pf[2];
-
- if (pipe(pf)<0)
- pf[0] = pf[1] = -1;
- if (fork()==0) {
- close(0);
- close(1);
- dup(pf[0]);
- dup(pf[1]);
- execl("/usr/lib/makekey", "-", 0);
- execl("/lib/makekey", "-", 0);
- exit(1);
- }
- write(pf[1], buffer, 10);
- if (wait((int *)NULL)==-1 || read(pf[0], buffer, 13)!=13)
- error("crypt: cannot generate key");
- close(pf[0]);
- close(pf[1]);
- /* end of nonportable part */
-}
projects / unix-history / blobdiff