1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
/*
* Off-the-Record Messaging library
* Copyright (C) 2004-2008 Ian Goldberg, Chris Alexander, Nikita Borisov
* <otr@cypherpunks.ca>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of version 2.1 of the GNU Lesser General
* Public License as published by the Free Software Foundation.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __DH_H__
#define __DH_H__
#define DH1536_GROUP_ID 5
typedef struct {
unsigned int groupid;
gcry_mpi_t priv, pub;
} DH_keypair;
/* Which half of the secure session id should be shown in bold? */
typedef enum {
OTRL_SESSIONID_FIRST_HALF_BOLD,
OTRL_SESSIONID_SECOND_HALF_BOLD
} OtrlSessionIdHalf;
typedef struct {
unsigned char sendctr[16];
unsigned char rcvctr[16];
gcry_cipher_hd_t sendenc;
gcry_cipher_hd_t rcvenc;
gcry_md_hd_t sendmac;
unsigned char sendmackey[20];
int sendmacused;
gcry_md_hd_t rcvmac;
unsigned char rcvmackey[20];
int rcvmacused;
} DH_sesskeys;
/*
* Call this once, at plugin load time. It sets up the modulus and
* generator MPIs.
*/
void otrl_dh_init(void);
/*
* Initialize the fields of a DH keypair.
*/
void otrl_dh_keypair_init(DH_keypair *kp);
/*
* Copy a DH_keypair.
*/
void otrl_dh_keypair_copy(DH_keypair *dst, const DH_keypair *src);
/*
* Deallocate the contents of a DH_keypair (but not the DH_keypair
* itself)
*/
void otrl_dh_keypair_free(DH_keypair *kp);
/*
* Generate a DH keypair for a specified group.
*/
gcry_error_t otrl_dh_gen_keypair(unsigned int groupid, DH_keypair *kp);
/*
* Construct session keys from a DH keypair and someone else's public
* key.
*/
gcry_error_t otrl_dh_session(DH_sesskeys *sess, const DH_keypair *kp,
gcry_mpi_t y);
/*
* Compute the secure session id, two encryption keys, and four MAC keys
* given our DH key and their DH public key.
*/
gcry_error_t otrl_dh_compute_v2_auth_keys(const DH_keypair *our_dh,
gcry_mpi_t their_pub, unsigned char *sessionid, size_t *sessionidlenp,
gcry_cipher_hd_t *enc_c, gcry_cipher_hd_t *enc_cp,
gcry_md_hd_t *mac_m1, gcry_md_hd_t *mac_m1p,
gcry_md_hd_t *mac_m2, gcry_md_hd_t *mac_m2p);
/*
* Compute the secure session id, given our DH key and their DH public
* key.
*/
gcry_error_t otrl_dh_compute_v1_session_id(const DH_keypair *our_dh,
gcry_mpi_t their_pub, unsigned char *sessionid, size_t *sessionidlenp,
OtrlSessionIdHalf *halfp);
/*
* Deallocate the contents of a DH_sesskeys (but not the DH_sesskeys
* itself)
*/
void otrl_dh_session_free(DH_sesskeys *sess);
/*
* Blank out the contents of a DH_sesskeys (without releasing it)
*/
void otrl_dh_session_blank(DH_sesskeys *sess);
/* Increment the top half of a counter block */
void otrl_dh_incctr(unsigned char *ctr);
/* Compare two counter values (8 bytes each). Return 0 if ctr1 == ctr2,
* < 0 if ctr1 < ctr2 (as unsigned 64-bit values), > 0 if ctr1 > ctr2. */
int otrl_dh_cmpctr(const unsigned char *ctr1, const unsigned char *ctr2);
#endif
|
