wolf SSL / CyaSSL-2.9.4

SSL/TLS Library

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CyaSSL is SSL/TLS library for embedded systems.

wolfssl.com

ctaocrypt/src/dh.c@0:9d17e4342598, 2014-04-20 (annotated)

Committer:
wolfSSL
Date:
Sun Apr 20 12:40:57 2014 +0000
Revision:
0:9d17e4342598
CyaSSL SSL/TLS Library 2.9.4;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
wolfSSL 0:9d17e4342598 1 /* dh.c
wolfSSL 0:9d17e4342598 2 *
wolfSSL 0:9d17e4342598 3 * Copyright (C) 2006-2013 wolfSSL Inc.
wolfSSL 0:9d17e4342598 4 *
wolfSSL 0:9d17e4342598 5 * This file is part of CyaSSL.
wolfSSL 0:9d17e4342598 6 *
wolfSSL 0:9d17e4342598 7 * CyaSSL is free software; you can redistribute it and/or modify
wolfSSL 0:9d17e4342598 8 * it under the terms of the GNU General Public License as published by
wolfSSL 0:9d17e4342598 9 * the Free Software Foundation; either version 2 of the License, or
wolfSSL 0:9d17e4342598 10 * (at your option) any later version.
wolfSSL 0:9d17e4342598 11 *
wolfSSL 0:9d17e4342598 12 * CyaSSL is distributed in the hope that it will be useful,
wolfSSL 0:9d17e4342598 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
wolfSSL 0:9d17e4342598 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
wolfSSL 0:9d17e4342598 15 * GNU General Public License for more details.
wolfSSL 0:9d17e4342598 16 *
wolfSSL 0:9d17e4342598 17 * You should have received a copy of the GNU General Public License
wolfSSL 0:9d17e4342598 18 * along with this program; if not, write to the Free Software
wolfSSL 0:9d17e4342598 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
wolfSSL 0:9d17e4342598 20 */
wolfSSL 0:9d17e4342598 21
wolfSSL 0:9d17e4342598 22 #ifdef HAVE_CONFIG_H
wolfSSL 0:9d17e4342598 23 #include <config.h>
wolfSSL 0:9d17e4342598 24 #endif
wolfSSL 0:9d17e4342598 25
wolfSSL 0:9d17e4342598 26 #include <cyassl/ctaocrypt/settings.h>
wolfSSL 0:9d17e4342598 27
wolfSSL 0:9d17e4342598 28 #ifndef NO_DH
wolfSSL 0:9d17e4342598 29
wolfSSL 0:9d17e4342598 30 #include <cyassl/ctaocrypt/dh.h>
wolfSSL 0:9d17e4342598 31 #include <cyassl/ctaocrypt/error-crypt.h>
wolfSSL 0:9d17e4342598 32
wolfSSL 0:9d17e4342598 33 #ifndef USER_MATH_LIB
wolfSSL 0:9d17e4342598 34 #include <math.h>
wolfSSL 0:9d17e4342598 35 #define XPOW(x,y) pow((x),(y))
wolfSSL 0:9d17e4342598 36 #define XLOG(x) log((x))
wolfSSL 0:9d17e4342598 37 #else
wolfSSL 0:9d17e4342598 38 /* user's own math lib */
wolfSSL 0:9d17e4342598 39 #endif
wolfSSL 0:9d17e4342598 40
wolfSSL 0:9d17e4342598 41
wolfSSL 0:9d17e4342598 42 #ifndef min
wolfSSL 0:9d17e4342598 43
wolfSSL 0:9d17e4342598 44 static INLINE word32 min(word32 a, word32 b)
wolfSSL 0:9d17e4342598 45 {
wolfSSL 0:9d17e4342598 46 return a > b ? b : a;
wolfSSL 0:9d17e4342598 47 }
wolfSSL 0:9d17e4342598 48
wolfSSL 0:9d17e4342598 49 #endif /* min */
wolfSSL 0:9d17e4342598 50
wolfSSL 0:9d17e4342598 51
wolfSSL 0:9d17e4342598 52 void InitDhKey(DhKey* key)
wolfSSL 0:9d17e4342598 53 {
wolfSSL 0:9d17e4342598 54 (void)key;
wolfSSL 0:9d17e4342598 55 /* TomsFastMath doesn't use memory allocation */
wolfSSL 0:9d17e4342598 56 #ifndef USE_FAST_MATH
wolfSSL 0:9d17e4342598 57 key->p.dp = 0;
wolfSSL 0:9d17e4342598 58 key->g.dp = 0;
wolfSSL 0:9d17e4342598 59 #endif
wolfSSL 0:9d17e4342598 60 }
wolfSSL 0:9d17e4342598 61
wolfSSL 0:9d17e4342598 62
wolfSSL 0:9d17e4342598 63 void FreeDhKey(DhKey* key)
wolfSSL 0:9d17e4342598 64 {
wolfSSL 0:9d17e4342598 65 (void)key;
wolfSSL 0:9d17e4342598 66 /* TomsFastMath doesn't use memory allocation */
wolfSSL 0:9d17e4342598 67 #ifndef USE_FAST_MATH
wolfSSL 0:9d17e4342598 68 mp_clear(&key->p);
wolfSSL 0:9d17e4342598 69 mp_clear(&key->g);
wolfSSL 0:9d17e4342598 70 #endif
wolfSSL 0:9d17e4342598 71 }
wolfSSL 0:9d17e4342598 72
wolfSSL 0:9d17e4342598 73
wolfSSL 0:9d17e4342598 74 static word32 DiscreteLogWorkFactor(word32 n)
wolfSSL 0:9d17e4342598 75 {
wolfSSL 0:9d17e4342598 76 /* assuming discrete log takes about the same time as factoring */
wolfSSL 0:9d17e4342598 77 if (n<5)
wolfSSL 0:9d17e4342598 78 return 0;
wolfSSL 0:9d17e4342598 79 else
wolfSSL 0:9d17e4342598 80 return (word32)(2.4 * XPOW((double)n, 1.0/3.0) *
wolfSSL 0:9d17e4342598 81 XPOW(XLOG((double)n), 2.0/3.0) - 5);
wolfSSL 0:9d17e4342598 82 }
wolfSSL 0:9d17e4342598 83
wolfSSL 0:9d17e4342598 84
wolfSSL 0:9d17e4342598 85 static void GeneratePrivate(DhKey* key, RNG* rng, byte* priv, word32* privSz)
wolfSSL 0:9d17e4342598 86 {
wolfSSL 0:9d17e4342598 87 word32 sz = mp_unsigned_bin_size(&key->p);
wolfSSL 0:9d17e4342598 88 sz = min(sz, 2 * DiscreteLogWorkFactor(sz * CYASSL_BIT_SIZE) /
wolfSSL 0:9d17e4342598 89 CYASSL_BIT_SIZE + 1);
wolfSSL 0:9d17e4342598 90 RNG_GenerateBlock(rng, priv, sz);
wolfSSL 0:9d17e4342598 91 priv[0] |= 0x0C;
wolfSSL 0:9d17e4342598 92
wolfSSL 0:9d17e4342598 93 *privSz = sz;
wolfSSL 0:9d17e4342598 94 }
wolfSSL 0:9d17e4342598 95
wolfSSL 0:9d17e4342598 96
wolfSSL 0:9d17e4342598 97 static int GeneratePublic(DhKey* key, const byte* priv, word32 privSz,
wolfSSL 0:9d17e4342598 98 byte* pub, word32* pubSz)
wolfSSL 0:9d17e4342598 99 {
wolfSSL 0:9d17e4342598 100 int ret = 0;
wolfSSL 0:9d17e4342598 101
wolfSSL 0:9d17e4342598 102 mp_int x;
wolfSSL 0:9d17e4342598 103 mp_int y;
wolfSSL 0:9d17e4342598 104
wolfSSL 0:9d17e4342598 105 if (mp_init_multi(&x, &y, 0, 0, 0, 0) != MP_OKAY)
wolfSSL 0:9d17e4342598 106 return MP_INIT_E;
wolfSSL 0:9d17e4342598 107
wolfSSL 0:9d17e4342598 108 if (mp_read_unsigned_bin(&x, priv, privSz) != MP_OKAY)
wolfSSL 0:9d17e4342598 109 ret = MP_READ_E;
wolfSSL 0:9d17e4342598 110
wolfSSL 0:9d17e4342598 111 if (ret == 0 && mp_exptmod(&key->g, &x, &key->p, &y) != MP_OKAY)
wolfSSL 0:9d17e4342598 112 ret = MP_EXPTMOD_E;
wolfSSL 0:9d17e4342598 113
wolfSSL 0:9d17e4342598 114 if (ret == 0 && mp_to_unsigned_bin(&y, pub) != MP_OKAY)
wolfSSL 0:9d17e4342598 115 ret = MP_TO_E;
wolfSSL 0:9d17e4342598 116
wolfSSL 0:9d17e4342598 117 if (ret == 0)
wolfSSL 0:9d17e4342598 118 *pubSz = mp_unsigned_bin_size(&y);
wolfSSL 0:9d17e4342598 119
wolfSSL 0:9d17e4342598 120 mp_clear(&y);
wolfSSL 0:9d17e4342598 121 mp_clear(&x);
wolfSSL 0:9d17e4342598 122
wolfSSL 0:9d17e4342598 123 return ret;
wolfSSL 0:9d17e4342598 124 }
wolfSSL 0:9d17e4342598 125
wolfSSL 0:9d17e4342598 126
wolfSSL 0:9d17e4342598 127 int DhGenerateKeyPair(DhKey* key, RNG* rng, byte* priv, word32* privSz,
wolfSSL 0:9d17e4342598 128 byte* pub, word32* pubSz)
wolfSSL 0:9d17e4342598 129 {
wolfSSL 0:9d17e4342598 130 GeneratePrivate(key, rng, priv, privSz);
wolfSSL 0:9d17e4342598 131 return GeneratePublic(key, priv, *privSz, pub, pubSz);
wolfSSL 0:9d17e4342598 132
wolfSSL 0:9d17e4342598 133 }
wolfSSL 0:9d17e4342598 134
wolfSSL 0:9d17e4342598 135 int DhAgree(DhKey* key, byte* agree, word32* agreeSz, const byte* priv,
wolfSSL 0:9d17e4342598 136 word32 privSz, const byte* otherPub, word32 pubSz)
wolfSSL 0:9d17e4342598 137 {
wolfSSL 0:9d17e4342598 138 int ret = 0;
wolfSSL 0:9d17e4342598 139
wolfSSL 0:9d17e4342598 140 mp_int x;
wolfSSL 0:9d17e4342598 141 mp_int y;
wolfSSL 0:9d17e4342598 142 mp_int z;
wolfSSL 0:9d17e4342598 143
wolfSSL 0:9d17e4342598 144 if (mp_init_multi(&x, &y, &z, 0, 0, 0) != MP_OKAY)
wolfSSL 0:9d17e4342598 145 return MP_INIT_E;
wolfSSL 0:9d17e4342598 146
wolfSSL 0:9d17e4342598 147 if (mp_read_unsigned_bin(&x, priv, privSz) != MP_OKAY)
wolfSSL 0:9d17e4342598 148 ret = MP_READ_E;
wolfSSL 0:9d17e4342598 149
wolfSSL 0:9d17e4342598 150 if (ret == 0 && mp_read_unsigned_bin(&y, otherPub, pubSz) != MP_OKAY)
wolfSSL 0:9d17e4342598 151 ret = MP_READ_E;
wolfSSL 0:9d17e4342598 152
wolfSSL 0:9d17e4342598 153 if (ret == 0 && mp_exptmod(&y, &x, &key->p, &z) != MP_OKAY)
wolfSSL 0:9d17e4342598 154 ret = MP_EXPTMOD_E;
wolfSSL 0:9d17e4342598 155
wolfSSL 0:9d17e4342598 156 if (ret == 0 && mp_to_unsigned_bin(&z, agree) != MP_OKAY)
wolfSSL 0:9d17e4342598 157 ret = MP_TO_E;
wolfSSL 0:9d17e4342598 158
wolfSSL 0:9d17e4342598 159 if (ret == 0)
wolfSSL 0:9d17e4342598 160 *agreeSz = mp_unsigned_bin_size(&z);
wolfSSL 0:9d17e4342598 161
wolfSSL 0:9d17e4342598 162 mp_clear(&z);
wolfSSL 0:9d17e4342598 163 mp_clear(&y);
wolfSSL 0:9d17e4342598 164 mp_clear(&x);
wolfSSL 0:9d17e4342598 165
wolfSSL 0:9d17e4342598 166 return ret;
wolfSSL 0:9d17e4342598 167 }
wolfSSL 0:9d17e4342598 168
wolfSSL 0:9d17e4342598 169
wolfSSL 0:9d17e4342598 170 #endif /* NO_DH */
wolfSSL 0:9d17e4342598 171