server/keygen.c

/*
 * Copyright 2015-2016 Rivoreo
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 2 of the License, or (at your
 * option) any later version.
 * 
 * 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.
 */

#include "ecc.c"
#include "syncrw.h"
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>

static int write_key(int fd, const ECIES_privkey_t *privkey, const ECIES_pubkey_t *pubkey) {
	int s1 = sync_write(fd, &privkey->k, ECIES_KEY_SIZE);
	if(s1 < ECIES_KEY_SIZE) return s1;
	int s2 = sync_write(fd, &pubkey->x, ECIES_KEY_SIZE);
	if(s2 < ECIES_KEY_SIZE) {
		if(s2 < 0) return -1;
		return s1 + s2;
	}
	int s3 = sync_write(fd, &pubkey->y, ECIES_KEY_SIZE);
	if(s3 < 0) return -1;
	return s1 + s2 + s3;
}

int main() {
	int server_key_fd = open("serverkey", O_WRONLY | O_CREAT | O_EXCL, 0600);
	if(server_key_fd == -1) {
		perror("serverkey");
		return 1;
	}
	int client_key_fd = open("clientkey", O_WRONLY | O_CREAT | O_EXCL, 0600);
	if(client_key_fd == -1) {
		perror("clientkey");
		return 1;
	}

	ECIES_privkey_t server_private_key;
	ECIES_pubkey_t server_publib_key;
	ECIES_privkey_t client_private_key;
	ECIES_pubkey_t client_publib_key;
	ECIES_generate_keys(&server_private_key, &client_publib_key);
	ECIES_generate_keys(&client_private_key, &server_publib_key);

	int s = write_key(server_key_fd, &server_private_key, &server_publib_key);
	if(s < ECIES_KEY_SIZE * 3) {
		if(s < 0) perror("serverkey");
		else fprintf(stderr, "writting to file serverkey finished too early (%d < %d)\n", s, ECIES_KEY_SIZE * 3);
		return 1;
	}
	s = write_key(client_key_fd, &client_private_key, &client_publib_key);
	if(s < ECIES_KEY_SIZE * 3) {
		if(s < 0) perror("clientkey");
		else fprintf(stderr, "writting to file clientkey finished too early (%d < %d)\n", s, ECIES_KEY_SIZE * 3);
		return 1;
	}

	if(close(server_key_fd) < 0) {
		perror("serverkey");
		return 1;
	}
	if(close(client_key_fd) < 0) {
		perror("clientkey");
		return 1;
	}

	puts("serverkey and clientkey are saved into current directory");
	return 0;
}