Francois Berder / cyassl-lib

fork of cyassl-lib

Dependents:   TLS_cyassl TLS_cyassl

ctaocrypt/src/dh.c@4:f377303c41be, 2013-09-16 (annotated)

Committer:
feb11
Date:
Mon Sep 16 09:53:35 2013 +0000
Revision:
4:f377303c41be
Parent:
0:714293de3836 
changed settings

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ashleymills 0:714293de3836 1 /* dh.c
ashleymills 0:714293de3836 2 *
ashleymills 0:714293de3836 3 * Copyright (C) 2006-2013 wolfSSL Inc.
ashleymills 0:714293de3836 4 *
ashleymills 0:714293de3836 5 * This file is part of CyaSSL.
ashleymills 0:714293de3836 6 *
ashleymills 0:714293de3836 7 * CyaSSL is free software; you can redistribute it and/or modify
ashleymills 0:714293de3836 8 * it under the terms of the GNU General Public License as published by
ashleymills 0:714293de3836 9 * the Free Software Foundation; either version 2 of the License, or
ashleymills 0:714293de3836 10 * (at your option) any later version.
ashleymills 0:714293de3836 11 *
ashleymills 0:714293de3836 12 * CyaSSL is distributed in the hope that it will be useful,
ashleymills 0:714293de3836 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
ashleymills 0:714293de3836 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
ashleymills 0:714293de3836 15 * GNU General Public License for more details.
ashleymills 0:714293de3836 16 *
ashleymills 0:714293de3836 17 * You should have received a copy of the GNU General Public License
ashleymills 0:714293de3836 18 * along with this program; if not, write to the Free Software
ashleymills 0:714293de3836 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
ashleymills 0:714293de3836 20 */
ashleymills 0:714293de3836 21
ashleymills 0:714293de3836 22 #ifdef HAVE_CONFIG_H
ashleymills 0:714293de3836 23 #include <config.h>
ashleymills 0:714293de3836 24 #endif
ashleymills 0:714293de3836 25
ashleymills 0:714293de3836 26 #include <cyassl/ctaocrypt/settings.h>
ashleymills 0:714293de3836 27
ashleymills 0:714293de3836 28 #ifndef NO_DH
ashleymills 0:714293de3836 29
ashleymills 0:714293de3836 30 #include <cyassl/ctaocrypt/dh.h>
ashleymills 0:714293de3836 31 #include <cyassl/ctaocrypt/ctaoerror2.h>
ashleymills 0:714293de3836 32
ashleymills 0:714293de3836 33 #ifndef USER_MATH_LIB
ashleymills 0:714293de3836 34 #include <math.h>
ashleymills 0:714293de3836 35 #define XPOW(x,y) pow((x),(y))
ashleymills 0:714293de3836 36 #define XLOG(x) log((x))
ashleymills 0:714293de3836 37 #else
ashleymills 0:714293de3836 38 /* user's own math lib */
ashleymills 0:714293de3836 39 #endif
ashleymills 0:714293de3836 40
ashleymills 0:714293de3836 41
ashleymills 0:714293de3836 42 #ifndef min
ashleymills 0:714293de3836 43
ashleymills 0:714293de3836 44 static INLINE word32 min(word32 a, word32 b)
ashleymills 0:714293de3836 45 {
ashleymills 0:714293de3836 46 return a > b ? b : a;
ashleymills 0:714293de3836 47 }
ashleymills 0:714293de3836 48
ashleymills 0:714293de3836 49 #endif /* min */
ashleymills 0:714293de3836 50
ashleymills 0:714293de3836 51
ashleymills 0:714293de3836 52 void InitDhKey(DhKey* key)
ashleymills 0:714293de3836 53 {
ashleymills 0:714293de3836 54 (void)key;
ashleymills 0:714293de3836 55 /* TomsFastMath doesn't use memory allocation */
ashleymills 0:714293de3836 56 #ifndef USE_FAST_MATH
ashleymills 0:714293de3836 57 key->p.dp = 0;
ashleymills 0:714293de3836 58 key->g.dp = 0;
ashleymills 0:714293de3836 59 #endif
ashleymills 0:714293de3836 60 }
ashleymills 0:714293de3836 61
ashleymills 0:714293de3836 62
ashleymills 0:714293de3836 63 void FreeDhKey(DhKey* key)
ashleymills 0:714293de3836 64 {
ashleymills 0:714293de3836 65 (void)key;
ashleymills 0:714293de3836 66 /* TomsFastMath doesn't use memory allocation */
ashleymills 0:714293de3836 67 #ifndef USE_FAST_MATH
ashleymills 0:714293de3836 68 mp_clear(&key->p);
ashleymills 0:714293de3836 69 mp_clear(&key->g);
ashleymills 0:714293de3836 70 #endif
ashleymills 0:714293de3836 71 }
ashleymills 0:714293de3836 72
ashleymills 0:714293de3836 73
ashleymills 0:714293de3836 74 static word32 DiscreteLogWorkFactor(word32 n)
ashleymills 0:714293de3836 75 {
ashleymills 0:714293de3836 76 /* assuming discrete log takes about the same time as factoring */
ashleymills 0:714293de3836 77 if (n<5)
ashleymills 0:714293de3836 78 return 0;
ashleymills 0:714293de3836 79 else
ashleymills 0:714293de3836 80 return (word32)(2.4 * XPOW((double)n, 1.0/3.0) *
ashleymills 0:714293de3836 81 XPOW(XLOG((double)n), 2.0/3.0) - 5);
ashleymills 0:714293de3836 82 }
ashleymills 0:714293de3836 83
ashleymills 0:714293de3836 84
ashleymills 0:714293de3836 85 static void GeneratePrivate(DhKey* key, RNG* rng, byte* priv, word32* privSz)
ashleymills 0:714293de3836 86 {
ashleymills 0:714293de3836 87 word32 sz = mp_unsigned_bin_size(&key->p);
ashleymills 0:714293de3836 88 sz = min(sz, 2 * DiscreteLogWorkFactor(sz * CYASSL_BIT_SIZE) /
ashleymills 0:714293de3836 89 CYASSL_BIT_SIZE + 1);
ashleymills 0:714293de3836 90 RNG_GenerateBlock(rng, priv, sz);
ashleymills 0:714293de3836 91 priv[0] |= 0x0C;
ashleymills 0:714293de3836 92
ashleymills 0:714293de3836 93 *privSz = sz;
ashleymills 0:714293de3836 94 }
ashleymills 0:714293de3836 95
ashleymills 0:714293de3836 96
ashleymills 0:714293de3836 97 static int GeneratePublic(DhKey* key, const byte* priv, word32 privSz,
ashleymills 0:714293de3836 98 byte* pub, word32* pubSz)
ashleymills 0:714293de3836 99 {
ashleymills 0:714293de3836 100 int ret = 0;
ashleymills 0:714293de3836 101
ashleymills 0:714293de3836 102 mp_int x;
ashleymills 0:714293de3836 103 mp_int y;
ashleymills 0:714293de3836 104
ashleymills 0:714293de3836 105 if (mp_init_multi(&x, &y, 0, 0, 0, 0) != MP_OKAY)
ashleymills 0:714293de3836 106 return MP_INIT_E;
ashleymills 0:714293de3836 107
ashleymills 0:714293de3836 108 if (mp_read_unsigned_bin(&x, priv, privSz) != MP_OKAY)
ashleymills 0:714293de3836 109 ret = MP_READ_E;
ashleymills 0:714293de3836 110
ashleymills 0:714293de3836 111 if (ret == 0 && mp_exptmod(&key->g, &x, &key->p, &y) != MP_OKAY)
ashleymills 0:714293de3836 112 ret = MP_EXPTMOD_E;
ashleymills 0:714293de3836 113
ashleymills 0:714293de3836 114 if (ret == 0 && mp_to_unsigned_bin(&y, pub) != MP_OKAY)
ashleymills 0:714293de3836 115 ret = MP_TO_E;
ashleymills 0:714293de3836 116
ashleymills 0:714293de3836 117 if (ret == 0)
ashleymills 0:714293de3836 118 *pubSz = mp_unsigned_bin_size(&y);
ashleymills 0:714293de3836 119
ashleymills 0:714293de3836 120 mp_clear(&y);
ashleymills 0:714293de3836 121 mp_clear(&x);
ashleymills 0:714293de3836 122
ashleymills 0:714293de3836 123 return ret;
ashleymills 0:714293de3836 124 }
ashleymills 0:714293de3836 125
ashleymills 0:714293de3836 126
ashleymills 0:714293de3836 127 int DhGenerateKeyPair(DhKey* key, RNG* rng, byte* priv, word32* privSz,
ashleymills 0:714293de3836 128 byte* pub, word32* pubSz)
ashleymills 0:714293de3836 129 {
ashleymills 0:714293de3836 130 GeneratePrivate(key, rng, priv, privSz);
ashleymills 0:714293de3836 131 return GeneratePublic(key, priv, *privSz, pub, pubSz);
ashleymills 0:714293de3836 132
ashleymills 0:714293de3836 133 }
ashleymills 0:714293de3836 134
ashleymills 0:714293de3836 135 int DhAgree(DhKey* key, byte* agree, word32* agreeSz, const byte* priv,
ashleymills 0:714293de3836 136 word32 privSz, const byte* otherPub, word32 pubSz)
ashleymills 0:714293de3836 137 {
ashleymills 0:714293de3836 138 int ret = 0;
ashleymills 0:714293de3836 139
ashleymills 0:714293de3836 140 mp_int x;
ashleymills 0:714293de3836 141 mp_int y;
ashleymills 0:714293de3836 142 mp_int z;
ashleymills 0:714293de3836 143
ashleymills 0:714293de3836 144 if (mp_init_multi(&x, &y, &z, 0, 0, 0) != MP_OKAY)
ashleymills 0:714293de3836 145 return MP_INIT_E;
ashleymills 0:714293de3836 146
ashleymills 0:714293de3836 147 if (mp_read_unsigned_bin(&x, priv, privSz) != MP_OKAY)
ashleymills 0:714293de3836 148 ret = MP_READ_E;
ashleymills 0:714293de3836 149
ashleymills 0:714293de3836 150 if (ret == 0 && mp_read_unsigned_bin(&y, otherPub, pubSz) != MP_OKAY)
ashleymills 0:714293de3836 151 ret = MP_READ_E;
ashleymills 0:714293de3836 152
ashleymills 0:714293de3836 153 if (ret == 0 && mp_exptmod(&y, &x, &key->p, &z) != MP_OKAY)
ashleymills 0:714293de3836 154 ret = MP_EXPTMOD_E;
ashleymills 0:714293de3836 155
ashleymills 0:714293de3836 156 if (ret == 0 && mp_to_unsigned_bin(&z, agree) != MP_OKAY)
ashleymills 0:714293de3836 157 ret = MP_TO_E;
ashleymills 0:714293de3836 158
ashleymills 0:714293de3836 159 if (ret == 0)
ashleymills 0:714293de3836 160 *agreeSz = mp_unsigned_bin_size(&z);
ashleymills 0:714293de3836 161
ashleymills 0:714293de3836 162 mp_clear(&z);
ashleymills 0:714293de3836 163 mp_clear(&y);
ashleymills 0:714293de3836 164 mp_clear(&x);
ashleymills 0:714293de3836 165
ashleymills 0:714293de3836 166 return ret;
ashleymills 0:714293de3836 167 }
ashleymills 0:714293de3836 168
ashleymills 0:714293de3836 169
ashleymills 0:714293de3836 170 #endif /* NO_DH */
ashleymills 0:714293de3836 171