/*
* Off-the-Record Messaging Toolkit
* Copyright (C) 2004-2012 Ian Goldberg, Chris Alexander, Nikita Borisov
* <otr@cypherpunks.ca>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* system headers */
#include <stdio.h>
#include <stdlib.h>
/* toolkit headers */
#include "parse.h"
#include "sesskeys.h"
static void usage(const char *progname)
{
fprintf(stderr, "Usage: %s our_privkey their_pubkey\n"
"Calculate and display our public key, the session id, two AES keys,\n"
"and two MAC keys generated by the given DH private key and public key.\n",
progname);
exit(1);
}
int main(int argc, char **argv)
{
unsigned char *argbuf;
size_t argbuflen;
gcry_mpi_t our_x, our_y, their_y;
unsigned char *pubbuf;
size_t publen;
unsigned char sessionid[20], sendenc[16], rcvenc[16];
unsigned char sendmac[20], rcvmac[20];
int is_high;
if (argc != 3) {
usage(argv[0]);
}
argv_to_buf(&argbuf, &argbuflen, argv[1]);
/* Private keys are only 320 bits long, so check for that to make
* sure they didn't get the args the wrong way around */
if (!argbuf || argbuflen > 40) usage(argv[0]);
gcry_mpi_scan(&our_x, GCRYMPI_FMT_USG, argbuf, argbuflen, NULL);
free(argbuf);
argv_to_buf(&argbuf, &argbuflen, argv[2]);
if (!argbuf) usage(argv[0]);
gcry_mpi_scan(&their_y, GCRYMPI_FMT_USG, argbuf, argbuflen, NULL);
free(argbuf);
sesskeys_gen(sessionid, sendenc, rcvenc, &is_high, &our_y, our_x, their_y);
sesskeys_make_mac(sendmac, sendenc);
sesskeys_make_mac(rcvmac, rcvenc);
/* Print our public key into a buffer */
gcry_mpi_print(GCRYMPI_FMT_USG, NULL, 0, &publen, our_y);
pubbuf = malloc(publen);
if (!pubbuf) {
fprintf(stderr, "Out of memory!\n");
exit(1);
}
gcry_mpi_print(GCRYMPI_FMT_USG, pubbuf, publen, NULL, our_y);
puts("");
printf("We are the %s end of this key exchange.\n",
is_high ? "high" : "low");
puts("");
dump_data(stdout, "Our public key", pubbuf, publen);
puts("");
dump_data(stdout, "Session id", sessionid, 20);
puts("");
dump_data(stdout, "Sending AES key", sendenc, 16);
dump_data(stdout, "Sending MAC key", sendmac, 20);
dump_data(stdout, "Receiving AES key", rcvenc, 16);
dump_data(stdout, "Receiving MAC key", rcvmac, 20);
puts("");
fflush(stdout);
return 0;
}
