361 lines
6.9 KiB
C
361 lines
6.9 KiB
C
/*
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* Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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* This code was based on:
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* PC1 Cipher Algorithm ( Pukall Cipher 1 )
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* By Alexander PUKALL 1991
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* free code no restriction to use
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* please include the name of the Author in the final software
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* the Key is 128 bits
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* http://membres.lycos.fr/pc1/
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <unistd.h> /* for unlink() */
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#include <libgen.h>
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#include <getopt.h> /* for getopt() */
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#include <stdarg.h>
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#include <errno.h>
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#include <sys/stat.h>
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struct pc1_ctx {
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unsigned short ax;
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unsigned short bx;
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unsigned short cx;
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unsigned short dx;
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unsigned short si;
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unsigned short tmp;
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unsigned short x1a2;
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unsigned short x1a0[8];
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unsigned short res;
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unsigned short i;
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unsigned short inter;
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unsigned short cfc;
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unsigned short cfd;
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unsigned short compte;
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unsigned char cle[17];
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short c;
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};
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static void pc1_finish(struct pc1_ctx *pc1)
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{
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/* erase all variables */
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memset(pc1, 0, sizeof(struct pc1_ctx));
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}
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static void pc1_code(struct pc1_ctx *pc1)
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{
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pc1->dx = pc1->x1a2 + pc1->i;
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pc1->ax = pc1->x1a0[pc1->i];
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pc1->cx = 0x015a;
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pc1->bx = 0x4e35;
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pc1->tmp = pc1->ax;
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pc1->ax = pc1->si;
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pc1->si = pc1->tmp;
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pc1->tmp = pc1->ax;
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pc1->ax = pc1->dx;
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pc1->dx = pc1->tmp;
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if (pc1->ax != 0) {
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pc1->ax = pc1->ax * pc1->bx;
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}
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pc1->tmp = pc1->ax;
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pc1->ax = pc1->cx;
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pc1->cx = pc1->tmp;
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if (pc1->ax != 0) {
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pc1->ax = pc1->ax * pc1->si;
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pc1->cx = pc1->ax + pc1->cx;
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}
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pc1->tmp = pc1->ax;
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pc1->ax = pc1->si;
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pc1->si = pc1->tmp;
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pc1->ax = pc1->ax * pc1->bx;
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pc1->dx = pc1->cx + pc1->dx;
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pc1->ax = pc1->ax + 1;
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pc1->x1a2 = pc1->dx;
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pc1->x1a0[pc1->i] = pc1->ax;
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pc1->res = pc1->ax ^ pc1->dx;
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pc1->i = pc1->i + 1;
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}
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static void pc1_assemble(struct pc1_ctx *pc1)
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{
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pc1->x1a0[0] = (pc1->cle[0] * 256) + pc1->cle[1];
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pc1_code(pc1);
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pc1->inter = pc1->res;
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pc1->x1a0[1] = pc1->x1a0[0] ^ ((pc1->cle[2]*256) + pc1->cle[3]);
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pc1_code(pc1);
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pc1->inter = pc1->inter ^ pc1->res;
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pc1->x1a0[2] = pc1->x1a0[1] ^ ((pc1->cle[4]*256) + pc1->cle[5]);
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pc1_code(pc1);
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pc1->inter = pc1->inter ^ pc1->res;
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pc1->x1a0[3] = pc1->x1a0[2] ^ ((pc1->cle[6]*256) + pc1->cle[7]);
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pc1_code(pc1);
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pc1->inter = pc1->inter ^ pc1->res;
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pc1->x1a0[4] = pc1->x1a0[3] ^ ((pc1->cle[8]*256) + pc1->cle[9]);
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pc1_code(pc1);
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pc1->inter = pc1->inter ^ pc1->res;
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pc1->x1a0[5] = pc1->x1a0[4] ^ ((pc1->cle[10]*256) + pc1->cle[11]);
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pc1_code(pc1);
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pc1->inter = pc1->inter ^ pc1->res;
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pc1->x1a0[6] = pc1->x1a0[5] ^ ((pc1->cle[12]*256) + pc1->cle[13]);
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pc1_code(pc1);
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pc1->inter = pc1->inter ^ pc1->res;
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pc1->x1a0[7] = pc1->x1a0[6] ^ ((pc1->cle[14]*256) + pc1->cle[15]);
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pc1_code(pc1);
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pc1->inter = pc1->inter ^ pc1->res;
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pc1->i = 0;
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}
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static unsigned char pc1_decrypt(struct pc1_ctx *pc1, short c)
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{
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pc1_assemble(pc1);
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pc1->cfc = pc1->inter >> 8;
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pc1->cfd = pc1->inter & 255; /* cfc^cfd = random byte */
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c = c ^ (pc1->cfc ^ pc1->cfd);
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for (pc1->compte = 0; pc1->compte <= 15; pc1->compte++) {
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/* we mix the plaintext byte with the key */
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pc1->cle[pc1->compte] = pc1->cle[pc1->compte] ^ c;
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}
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return c;
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}
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static unsigned char pc1_encrypt(struct pc1_ctx *pc1, short c)
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{
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pc1_assemble(pc1);
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pc1->cfc = pc1->inter >> 8;
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pc1->cfd = pc1->inter & 255; /* cfc^cfd = random byte */
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for (pc1->compte = 0; pc1->compte <= 15; pc1->compte++) {
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/* we mix the plaintext byte with the key */
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pc1->cle[pc1->compte] = pc1->cle[pc1->compte] ^ c;
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}
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c = c ^ (pc1->cfc ^ pc1->cfd);
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return c;
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}
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static void pc1_init(struct pc1_ctx *pc1)
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{
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memset(pc1, 0, sizeof(struct pc1_ctx));
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/* ('Remsaalps!123456') is the key used, you can change it */
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strcpy(pc1->cle, "Remsaalps!123456");
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}
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static void pc1_decrypt_buf(struct pc1_ctx *pc1, unsigned char *buf,
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unsigned len)
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{
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unsigned i;
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for (i = 0; i < len; i++)
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buf[i] = pc1_decrypt(pc1, buf[i]);
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}
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static void pc1_encrypt_buf(struct pc1_ctx *pc1, unsigned char *buf,
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unsigned len)
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{
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unsigned i;
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for (i = 0; i < len; i++)
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buf[i] = pc1_encrypt(pc1, buf[i]);
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}
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/*
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* Globals
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*/
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static char *ifname;
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static char *progname;
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static char *ofname;
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static int decrypt;
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/*
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* Message macros
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*/
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#define ERR(fmt, ...) do { \
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fflush(0); \
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fprintf(stderr, "[%s] *** error: " fmt "\n", \
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progname, ## __VA_ARGS__ ); \
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} while (0)
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#define ERRS(fmt, ...) do { \
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int save = errno; \
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fflush(0); \
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fprintf(stderr, "[%s] *** error: " fmt "\n", \
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progname, ## __VA_ARGS__, strerror(save)); \
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} while (0)
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void usage(int status)
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{
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FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
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struct board_info *board;
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fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
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fprintf(stream,
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"\n"
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"Options:\n"
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" -d decrypt instead of encrypt"
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" -i <file> read input from the file <file>\n"
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" -o <file> write output to the file <file>\n"
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" -h show this screen\n"
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);
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exit(status);
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}
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#define BUFSIZE (64 * 1024)
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int main(int argc, char *argv[])
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{
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struct pc1_ctx pc1;
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int res = EXIT_FAILURE;
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int err;
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struct stat st;
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char *buf;
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unsigned total;
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FILE *outfile, *infile;
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progname = basename(argv[0]);
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while ( 1 ) {
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int c;
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c = getopt(argc, argv, "di:o:h");
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if (c == -1)
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break;
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switch (c) {
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case 'd':
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decrypt = 1;
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break;
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case 'i':
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ifname = optarg;
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break;
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case 'o':
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ofname = optarg;
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break;
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case 'h':
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usage(EXIT_SUCCESS);
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break;
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default:
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usage(EXIT_FAILURE);
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break;
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}
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}
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if (ifname == NULL) {
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ERR("no input file specified");
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goto err;
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}
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if (ofname == NULL) {
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ERR("no output file specified");
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goto err;
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}
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err = stat(ifname, &st);
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if (err){
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ERRS("stat failed on %s", ifname);
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goto err;
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}
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total = st.st_size;
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buf = malloc(BUFSIZE);
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if (!buf) {
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ERR("no memory for buffer\n");
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goto err;
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}
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infile = fopen(ifname, "r");
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if (infile == NULL) {
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ERRS("could not open \"%s\" for reading", ifname);
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goto err_free;
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}
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outfile = fopen(ofname, "w");
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if (outfile == NULL) {
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ERRS("could not open \"%s\" for writing", ofname);
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goto err_close_in;
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}
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pc1_init(&pc1);
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while (total > 0) {
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unsigned datalen;
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if (total > BUFSIZE)
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datalen = BUFSIZE;
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else
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datalen = total;
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errno = 0;
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fread(buf, datalen, 1, infile);
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if (errno != 0) {
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ERRS("unable to read from file %s", ifname);
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goto err_close_out;
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}
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if (decrypt)
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pc1_decrypt_buf(&pc1, buf, datalen);
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else
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pc1_encrypt_buf(&pc1, buf, datalen);
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errno = 0;
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fwrite(buf, datalen, 1, outfile);
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if (errno) {
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ERRS("unable to write to file %s", ofname);
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goto err_close_out;
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}
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total -= datalen;
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}
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pc1_finish(&pc1);
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res = EXIT_SUCCESS;
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out_flush:
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fflush(outfile);
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err_close_out:
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fclose(outfile);
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if (res != EXIT_SUCCESS) {
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unlink(ofname);
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}
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err_close_in:
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fclose(infile);
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err_free:
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free(buf);
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err:
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return res;
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}
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