23c30549af
I'm pretty skeptical that any crypto in telnet is worth using, but if we're ostensibly generating keys, arc4random is strictly better than the previous construct.
261 lines
6.7 KiB
C
261 lines
6.7 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* Dave Safford. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/* public key routines */
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/* functions:
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genkeys(char *public, char *secret)
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common_key(char *secret, char *public, desData *deskey)
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pk_encode(char *in, *out, DesData *deskey);
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pk_decode(char *in, *out, DesData *deskey);
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where
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char public[HEXKEYBYTES + 1];
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char secret[HEXKEYBYTES + 1];
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*/
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#include <sys/time.h>
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#include <openssl/des.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "mp.h"
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#include "pk.h"
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static void adjust(char keyout[HEXKEYBYTES+1], char *keyin);
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/*
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* Choose top 128 bits of the common key to use as our idea key.
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*/
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static void
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extractideakey(MINT *ck, IdeaData *ideakey)
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{
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MINT *a;
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MINT *z;
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short r;
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int i;
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short base = (1 << 8);
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char *k;
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z = mp_itom(0);
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a = mp_itom(0);
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mp_madd(ck, z, a);
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for (i = 0; i < ((KEYSIZE - 128) / 8); i++) {
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mp_sdiv(a, base, a, &r);
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}
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k = (char *)ideakey;
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for (i = 0; i < 16; i++) {
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mp_sdiv(a, base, a, &r);
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*k++ = r;
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}
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mp_mfree(z);
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mp_mfree(a);
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}
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/*
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* Choose middle 64 bits of the common key to use as our des key, possibly
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* overwriting the lower order bits by setting parity.
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*/
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static void
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extractdeskey(MINT *ck, DesData *deskey)
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{
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MINT *a;
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MINT *z;
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short r;
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int i;
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short base = (1 << 8);
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char *k;
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z = mp_itom(0);
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a = mp_itom(0);
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mp_madd(ck, z, a);
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for (i = 0; i < ((KEYSIZE - 64) / 2) / 8; i++) {
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mp_sdiv(a, base, a, &r);
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}
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k = (char *)deskey;
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for (i = 0; i < 8; i++) {
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mp_sdiv(a, base, a, &r);
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*k++ = r;
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}
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mp_mfree(z);
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mp_mfree(a);
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}
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/*
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* get common key from my secret key and his public key
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*/
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void
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common_key(char *xsecret, char *xpublic, IdeaData *ideakey, DesData *deskey)
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{
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MINT *public;
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MINT *secret;
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MINT *common;
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MINT *modulus = mp_xtom(HEXMODULUS);
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public = mp_xtom(xpublic);
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secret = mp_xtom(xsecret);
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common = mp_itom(0);
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mp_pow(public, secret, modulus, common);
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extractdeskey(common, deskey);
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extractideakey(common, ideakey);
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DES_set_odd_parity(deskey);
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mp_mfree(common);
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mp_mfree(secret);
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mp_mfree(public);
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mp_mfree(modulus);
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}
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/*
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* Generate a seed
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*/
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static void
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getseed(char *seed, int seedsize)
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{
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arc4random_buf(seed, seedsize);
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}
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/*
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* Generate a random public/secret key pair
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*/
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void
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genkeys(char *public, char *secret)
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{
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size_t i;
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# define BASEBITS (8*sizeof(short) - 1)
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# define BASE (1 << BASEBITS)
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MINT *pk = mp_itom(0);
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MINT *sk = mp_itom(0);
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MINT *tmp;
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MINT *base = mp_itom((short)BASE);
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MINT *root = mp_itom(PROOT);
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MINT *modulus = mp_xtom(HEXMODULUS);
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short r;
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unsigned short seed[KEYSIZE/BASEBITS + 1];
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char *xkey;
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getseed((char *)seed, sizeof(seed));
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for (i = 0; i < KEYSIZE/BASEBITS + 1; i++) {
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r = seed[i] % BASE;
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tmp = mp_itom(r);
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mp_mult(sk, base, sk);
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mp_madd(sk, tmp, sk);
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mp_mfree(tmp);
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}
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tmp = mp_itom(0);
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mp_mdiv(sk, modulus, tmp, sk);
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mp_mfree(tmp);
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mp_pow(root, sk, modulus, pk);
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xkey = mp_mtox(sk);
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adjust(secret, xkey);
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xkey = mp_mtox(pk);
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adjust(public, xkey);
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mp_mfree(sk);
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mp_mfree(base);
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mp_mfree(pk);
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mp_mfree(root);
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mp_mfree(modulus);
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}
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/*
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* Adjust the input key so that it is 0-filled on the left
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*/
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static void
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adjust(char keyout[HEXKEYBYTES+1], char *keyin)
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{
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char *p;
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char *s;
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for (p = keyin; *p; p++)
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;
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for (s = keyout + HEXKEYBYTES; p >= keyin; p--, s--) {
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*s = *p;
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}
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while (s >= keyout) {
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*s-- = '0';
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}
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}
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static char hextab[17] = "0123456789ABCDEF";
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/* given a DES key, cbc encrypt and translate input to terminated hex */
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void
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pk_encode(char *in, char *out, DesData *key)
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{
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char buf[256];
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DesData i;
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DES_key_schedule k;
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int l,op,deslen;
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memset(&i,0,sizeof(i));
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memset(buf,0,sizeof(buf));
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deslen = ((strlen(in) + 7)/8)*8;
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DES_key_sched(key, &k);
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DES_cbc_encrypt(in, buf, deslen, &k, &i, DES_ENCRYPT);
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for (l=0,op=0;l<deslen;l++) {
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out[op++] = hextab[(buf[l] & 0xf0) >> 4];
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out[op++] = hextab[(buf[l] & 0x0f)];
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}
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out[op] = '\0';
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}
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/* given a DES key, translate input from hex and decrypt */
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void
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pk_decode(char *in, char *out, DesData *key)
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{
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char buf[256];
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DesData i;
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DES_key_schedule k;
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int n1,n2,op;
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size_t l;
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memset(&i,0,sizeof(i));
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memset(buf,0,sizeof(buf));
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for (l=0,op=0;l<strlen(in)/2;l++,op+=2) {
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if (in[op] > '9')
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n1 = in[op] - 'A' + 10;
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else
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n1 = in[op] - '0';
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if (in[op+1] > '9')
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n2 = in[op+1] - 'A' + 10;
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else
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n2 = in[op+1] - '0';
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buf[l] = n1*16 +n2;
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}
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DES_key_sched(key, &k);
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DES_cbc_encrypt(buf, out, strlen(in) / 2, &k, &i, DES_DECRYPT);
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out[strlen(in)/2] = '\0';
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}
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