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
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
/*
* FILE: hmac.c
* AUTHORS: Colin Perkins
*
* HMAC message authentication (RFC2104)
*
* Copyright (c) 1998 University College London
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, is permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the Computer Science
* Department at University College London
* 4. Neither the name of the University nor of the Department may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "config_unix.h"
#include "config_win32.h"
#include "md5.h"
#include "hmac.h"
void hmac_md5(unsigned char *data, /* pointer to data stream */
int data_len, /* length of data stream */
unsigned char *key, /* pointer to authentication key */
int key_len, /* length of authentication key */
unsigned char digest[16]) /* caller digest to be filled in */
{
MD5_CTX context;
unsigned char k_ipad[65]; /* inner padding - key XORd with ipad */
unsigned char k_opad[65]; /* outer padding - key XORd with opad */
unsigned char tk[16];
int i;
/* If key is longer than 64 bytes reset it to key=MD5(key) */
if (key_len > 64) {
MD5_CTX tctx;
MD5Init(&tctx);
MD5Update(&tctx, key, key_len);
MD5Final(tk, &tctx);
key = tk;
key_len = 16;
}
/*
* The HMAC_MD5 transform looks like:
*
* MD5(K XOR opad, MD5(K XOR ipad, data))
*
* where K is an n byte key
* ipad is the byte 0x36 repeated 64 times
* opad is the byte 0x5c repeated 64 times
* and text is the data being protected
*/
/* Start out by storing key in pads */
memset(k_ipad, 0, sizeof(k_ipad));
memset(k_opad, 0, sizeof(k_opad));
memcpy(k_ipad, key, key_len);
memcpy(k_opad, key, key_len);
/* XOR key with ipad and opad values */
for (i=0; i<64; i++) {
k_ipad[i] ^= 0x36;
k_opad[i] ^= 0x5c;
}
/*
* perform inner MD5
*/
MD5Init(&context); /* init context for 1st pass */
MD5Update(&context, k_ipad, 64); /* start with inner pad */
MD5Update(&context, data, data_len); /* then text of datagram */
MD5Final(digest, &context); /* finish up 1st pass */
/*
* perform outer MD5
*/
MD5Init(&context); /* init context for 2nd pass */
MD5Update(&context, k_opad, 64); /* start with outer pad */
MD5Update(&context, digest, 16); /* then results of 1st hash */
MD5Final(digest, &context); /* finish up 2nd pass */
}
/*
* Test Vectors (Trailing '\0' of a character string not included in test):
*
* key = 0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b
* key_len = 16 bytes
* data = "Hi There"
* data_len = 8 bytes
* digest = 0x9294727a3638bb1c13f48ef8158bfc9d
*
* key = "Jefe"
* data = "what do ya want for nothing?"
* data_len = 28 bytes
* digest = 0x750c783e6ab0b503eaa86e310a5db738
*
* key = 0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
* key_len 16 bytes
* data = 0xDDDDDDDDDDDDDDDDDDDD...
* ..DDDDDDDDDDDDDDDDDDDD...
* ..DDDDDDDDDDDDDDDDDDDD...
* ..DDDDDDDDDDDDDDDDDDDD...
* ..DDDDDDDDDDDDDDDDDDDD
* data_len = 50 bytes
* digest = 0x56be34521d144c88dbb8c733f0e8b3f6
*/
#ifdef TEST_HMAC
int main()
{
unsigned char *key = "Jefe";
unsigned char *data = "what do ya want for nothing?";
unsigned char digest[16];
int i;
hmac_md5(data, 28, key, 4, digest);
for (i = 0; i < 16; i++) {
printf("%02x", digest[i]);
}
printf("\n");
return 0;
}
#endif
|
