crypto.c

Intercom 是一个 Unix系统上灵活的语音传输软件。支持标准音频压缩比如GSM, G.711, and G.72x和其他音频编码。Intercom专为高速网络设计来传输高品质的语音

/*  crypto.c -- Crypto interface for Intercom
    Copyright (C) 2001-2003  Shane Wegner
    This file is part of Intercom.

    Intercom 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.

    Intercom 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 version 2 of the GNU General Public
    License along with Intercom; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

    To contact the author, please send email to [e-mail].
    */

/* $Id: crypto.c,v 1.8 2003/02/13 20:22:49 shane Exp $ */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include <string.h>
#include <openssl/des.h>
#include <openssl/blowfish.h>
#include <openssl/md5.h>
#include <assert.h>

#include "crypto.h"
#include "protocol.h"
#include "intercom.h"

#ifdef CRYPTO_OLD_DES
#define DES_key_schedule des_key_schedule
#define DES_cblock des_cblock
#define DES_string_to_key des_string_to_key
#define DES_set_key des_set_key
#define DES_ncbc_encrypt des_ncbc_encrypt
static DES_key_schedule des_sched;
#else
static DES_key_schedule *des_sched;
#endif

int cr_type_fromstr(const char *s)
{
if (!strcasecmp(s, "des"))
return CALL_CRYPT_DES;
else if (!strcasecmp(s, "blowfish"))
return CALL_CRYPT_BLOWFISH;
else
return -1;
}

static void cr_des_set_key(const char *passphrase)
{
DES_cblock des_key;
DES_string_to_key(passphrase, &des_key);
DES_set_key(&des_key, des_sched);
}

static void cr_des_encrypt(const char *in, size_t inl, char *out, size_t *outl)
{
size_t l;
DES_cblock ivec;
memset(ivec, 0, 8);
l = (inl + 7) & (~7);
DES_ncbc_encrypt(in, out, l, des_sched, &ivec, DES_ENCRYPT);
*outl = l;
}

static void cr_des_decrypt(const char *in, size_t inl, char *out, size_t *outl)
{
DES_cblock ivec;
memset(ivec, 0, 8);
assert(((inl + 7) & (~7)) == inl);
DES_ncbc_encrypt(in, out, inl, des_sched, &ivec, DES_DECRYPT);
*outl = inl;
}

static BF_KEY bf_key;

static void cr_bf_set_key(const char *passphrase)
{
char md5[16];
MD5(passphrase, strlen(passphrase), md5);
BF_set_key(&bf_key, 16, md5);
}

static void cr_bf_encrypt(const char *in, size_t inl, char *out, size_t *outl)
{
size_t l;
char ivec[8];
memset(ivec, 0, 8);
l = (inl + 7) & (~7);
BF_cbc_encrypt(in, out, l, &bf_key, ivec, BF_ENCRYPT);
*outl = l;
}

static void cr_bf_decrypt(const char *in, size_t inl, char *out, size_t *outl)
{
char ivec[8];
memset(ivec, 0, 8);
assert(((inl + 7) & (~7)) == inl);
BF_cbc_encrypt(in, out, inl, &bf_key, ivec, BF_DECRYPT);
*outl = inl;
}

void cr_set_key(const char *passphrase)
{
switch(call.cryptinfo.type) {
case CALL_CRYPT_DES:
cr_des_set_key(passphrase);
break;
case CALL_CRYPT_BLOWFISH:
cr_bf_set_key(passphrase);
break;
default:
assert(0);
}
}

void cr_encrypt(const char *in, size_t inl, char *out, size_t *outl)
{
switch(call.cryptinfo.type) {
case CALL_CRYPT_DES:
cr_des_encrypt(in, inl, out, outl);
break;
case CALL_CRYPT_BLOWFISH:
cr_bf_encrypt(in, inl, out, outl);
break;
default:
assert(0);
}
}

void cr_decrypt(const char *in, size_t inl, char *out, size_t *outl)
{
switch(call.cryptinfo.type) {
case CALL_CRYPT_DES:
cr_des_decrypt(in, inl, out, outl);
break;
case CALL_CRYPT_BLOWFISH:
cr_bf_decrypt(in, inl, out, outl);
break;
default:
assert(0);
}
}