pk.c revision 1.1
1 /*- 2 * Copyright (c) 1991, 1993 3 * Dave Safford. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 */ 30 31 #include <sys/cdefs.h> 32 33 #ifdef notdef 34 __FBSDID("$FreeBSD: src/contrib/telnet/libtelnet/pk.c,v 1.10 2002/08/22 06:19:07 nsayer Exp $"); 35 #else 36 __RCSID("$NetBSD: pk.c,v 1.1 2005/02/19 21:55:52 christos Exp $"); 37 #endif 38 39 /* public key routines */ 40 /* functions: 41 genkeys(char *public, char *secret) 42 common_key(char *secret, char *public, desData *deskey) 43 pk_encode(char *in, *out, DesData *deskey); 44 pk_decode(char *in, *out, DesData *deskey); 45 where 46 char public[HEXKEYBYTES + 1]; 47 char secret[HEXKEYBYTES + 1]; 48 */ 49 50 #include <sys/time.h> 51 #include <openssl/des.h> 52 #include <fcntl.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 57 #include "mp.h" 58 #include "pk.h" 59 60 static void adjust(char keyout[HEXKEYBYTES+1], char *keyin); 61 62 /* 63 * Choose top 128 bits of the common key to use as our idea key. 64 */ 65 static void 66 extractideakey(MINT *ck, IdeaData *ideakey) 67 { 68 MINT *a; 69 MINT *z; 70 short r; 71 int i; 72 short base = (1 << 8); 73 char *k; 74 75 z = itom(0); 76 a = itom(0); 77 madd(ck, z, a); 78 for (i = 0; i < ((KEYSIZE - 128) / 8); i++) { 79 sdiv(a, base, a, &r); 80 } 81 k = (char *)ideakey; 82 for (i = 0; i < 16; i++) { 83 sdiv(a, base, a, &r); 84 *k++ = r; 85 } 86 mfree(z); 87 mfree(a); 88 } 89 90 /* 91 * Choose middle 64 bits of the common key to use as our des key, possibly 92 * overwriting the lower order bits by setting parity. 93 */ 94 static void 95 extractdeskey(MINT *ck, DesData *deskey) 96 { 97 MINT *a; 98 MINT *z; 99 short r; 100 int i; 101 short base = (1 << 8); 102 char *k; 103 104 z = itom(0); 105 a = itom(0); 106 madd(ck, z, a); 107 for (i = 0; i < ((KEYSIZE - 64) / 2) / 8; i++) { 108 sdiv(a, base, a, &r); 109 } 110 k = (char *)deskey; 111 for (i = 0; i < 8; i++) { 112 sdiv(a, base, a, &r); 113 *k++ = r; 114 } 115 mfree(z); 116 mfree(a); 117 } 118 119 /* 120 * get common key from my secret key and his public key 121 */ 122 void 123 common_key(char *xsecret, char *xpublic, IdeaData *ideakey, DesData *deskey) 124 { 125 MINT *public; 126 MINT *secret; 127 MINT *common; 128 MINT *modulus = xtom(HEXMODULUS); 129 130 public = xtom(xpublic); 131 secret = xtom(xsecret); 132 common = itom(0); 133 pow(public, secret, modulus, common); 134 extractdeskey(common, deskey); 135 extractideakey(common, ideakey); 136 des_set_odd_parity(deskey); 137 mfree(common); 138 mfree(secret); 139 mfree(public); 140 mfree(modulus); 141 } 142 143 /* 144 * Generate a seed 145 */ 146 static void 147 getseed(char *seed, int seedsize) 148 { 149 int i; 150 151 srandomdev(); 152 for (i = 0; i < seedsize; i++) { 153 seed[i] = random() & 0xff; 154 } 155 } 156 157 /* 158 * Generate a random public/secret key pair 159 */ 160 void 161 genkeys(char *public, char *secret) 162 { 163 size_t i; 164 165 # define BASEBITS (8*sizeof(short) - 1) 166 # define BASE (1 << BASEBITS) 167 168 MINT *pk = itom(0); 169 MINT *sk = itom(0); 170 MINT *tmp; 171 MINT *base = itom(BASE); 172 MINT *root = itom(PROOT); 173 MINT *modulus = xtom(HEXMODULUS); 174 short r; 175 unsigned short seed[KEYSIZE/BASEBITS + 1]; 176 char *xkey; 177 178 getseed((char *)seed, sizeof(seed)); 179 for (i = 0; i < KEYSIZE/BASEBITS + 1; i++) { 180 r = seed[i] % BASE; 181 tmp = itom(r); 182 mult(sk, base, sk); 183 madd(sk, tmp, sk); 184 mfree(tmp); 185 } 186 tmp = itom(0); 187 mdiv(sk, modulus, tmp, sk); 188 mfree(tmp); 189 pow(root, sk, modulus, pk); 190 xkey = mtox(sk); 191 adjust(secret, xkey); 192 xkey = mtox(pk); 193 adjust(public, xkey); 194 mfree(sk); 195 mfree(base); 196 mfree(pk); 197 mfree(root); 198 mfree(modulus); 199 } 200 201 /* 202 * Adjust the input key so that it is 0-filled on the left 203 */ 204 static void 205 adjust(char keyout[HEXKEYBYTES+1], char *keyin) 206 { 207 char *p; 208 char *s; 209 210 for (p = keyin; *p; p++) 211 ; 212 for (s = keyout + HEXKEYBYTES; p >= keyin; p--, s--) { 213 *s = *p; 214 } 215 while (s >= keyout) { 216 *s-- = '0'; 217 } 218 } 219 220 static char hextab[17] = "0123456789ABCDEF"; 221 222 /* given a DES key, cbc encrypt and translate input to terminated hex */ 223 void 224 pk_encode(char *in, char *out, DesData *key) 225 { 226 char buf[256]; 227 DesData i; 228 des_key_schedule k; 229 int l,op,deslen; 230 231 memset(&i,0,sizeof(i)); 232 memset(buf,0,sizeof(buf)); 233 deslen = ((strlen(in) + 7)/8)*8; 234 des_key_sched(key, k); 235 des_cbc_encrypt(in,buf,deslen, k,&i,DES_ENCRYPT); 236 for (l=0,op=0;l<deslen;l++) { 237 out[op++] = hextab[(buf[l] & 0xf0) >> 4]; 238 out[op++] = hextab[(buf[l] & 0x0f)]; 239 } 240 out[op] = '\0'; 241 } 242 243 /* given a DES key, translate input from hex and decrypt */ 244 void 245 pk_decode(char *in, char *out, DesData *key) 246 { 247 char buf[256]; 248 DesData i; 249 des_key_schedule k; 250 int n1,n2,op; 251 size_t l; 252 253 memset(&i,0,sizeof(i)); 254 memset(buf,0,sizeof(buf)); 255 for (l=0,op=0;l<strlen(in)/2;l++,op+=2) { 256 if (in[op] > '9') 257 n1 = in[op] - 'A' + 10; 258 else 259 n1 = in[op] - '0'; 260 if (in[op+1] > '9') 261 n2 = in[op+1] - 'A' + 10; 262 else 263 n2 = in[op+1] - '0'; 264 buf[l] = n1*16 +n2; 265 } 266 des_key_sched(key, k); 267 des_cbc_encrypt(buf,out,strlen(in)/2, k,&i,DES_DECRYPT); 268 out[strlen(in)/2] = '\0'; 269 } 270
Indexes created Wed Sep 24 02:09:48 GMT 2025