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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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vol_100
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194_01
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crypt1.c
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1985-11-14
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/* [CRYPT1.C of JUGPDS Vol.17]
*****************************************************************
* *
* Written by Hakuo Katayose (JUG-CP/M No.179) *
* 49-114 Kawauchi-Sanjuunin-machi *
* Sendai, Miyagi 980 *
* Phone: 0222-61-3219 *
* *
* Edited & tested by Y. Monma (JUG-C/M Disk Editor) *
* *
*****************************************************************
*/
/* crypt1 - encrypt and decrypt for binary file */
#include "stdio.h"
#define MAXKEY 32
main(argc, argv)
int argc;
char *argv[];
{
int i, keylen, cnt, n, fd, n2, fd2;
char key[MAXKEY], *p, *q;
char tbuf[(1024*30)];
p = tbuf;
if (argc < 4)
error("Usage: crypt0 key infile outfile");
strcpy(key, argv[1]);
keylen = strlen(key);
if ((fd = open( argv[2], 0)) == ERROR) {
fprintf(STDERR, "crypt1: can't open %s\n", *argv);
exit();
}
else if ((fd2 = creat( argv[3])) == ERROR) {
fprintf(STDERR, "crypt1: can't open %s\n", *argv);
exit();
}
else
while ((n = read(fd, p, 240) ) > 0) {
printf("%4d sectors READ.\n", n);
q = p;
cnt = n * 128;
for (i = 1; cnt--; i= i%keylen + 1)
*q++ ^= key[i];
n2 = write(fd2, p, n);
printf("%4d sectors WRITE.\n", n2);
if (n2 != n) {
break;
}
}
close(fd);
close(fd2);
}