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
|
/* hmac.h - TinyCrypt interface to an HMAC implementation */
/*
* Copyright (C) 2015 by Intel Corporation, All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - 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.
*
* - Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS 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 COPYRIGHT OWNER 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.
*/
/**
* @file
* @brief Interface to an HMAC implementation.
*
* Overview: HMAC is a message authentication code based on hash functions.
* TinyCrypt hard codes SHA-256 as the hash function. A message
* authentication code based on hash functions is also called a
* keyed cryptographic hash function since it performs a
* transformation specified by a key in an arbitrary length data
* set into a fixed length data set (also called tag).
*
* Security: The security of the HMAC depends on the length of the key and
* on the security of the hash function. Note that HMAC primitives
* are much less affected by collision attacks than their
* corresponding hash functions.
*
* Requires: SHA-256
*
* Usage: 1) call tc_hmac_set_key to set the HMAC key.
*
* 2) call tc_hmac_init to initialize a struct hash_state before
* processing the data.
*
* 3) call tc_hmac_update to process the next input segment;
* tc_hmac_update can be called as many times as needed to process
* all of the segments of the input; the order is important.
*
* 4) call tc_hmac_final to out put the tag.
*/
#ifndef __TC_HMAC_H__
#define __TC_HMAC_H__
#include <sha256.h>
struct tc_hmac_state_struct {
struct tc_sha256_state_struct hash_state; /* the internal state required by h */
uint8_t key[2*TC_SHA256_BLOCK_SIZE]; /* HMAC key schedule */
};
typedef struct tc_hmac_state_struct *TCHmacState_t;
/**
* @brief HMAC set key procedure
* Configures ctx to use key
* @return returns TC_SUCCESS (1)
* returns TC_FAIL (0) if
* ctx == NULL or
* key == NULL or
* key_size == 0
* @param ctx IN/OUT -- the struct tc_hmac_state_struct to initial
* @param key IN -- the HMAC key to configure
* @param key_size IN -- the HMAC key size
*/
int32_t tc_hmac_set_key(TCHmacState_t ctx, const uint8_t *key, uint32_t key_size);
/**
* @brief HMAC init procedure
* Initializes ctx to begin the next HMAC operation
* @return returns TC_SUCCESS (1)
* returns TC_FAIL (0) if: ctx == NULL or key == NULL
* @param ctx IN/OUT -- struct tc_hmac_state_struct buffer to init
*/
int32_t tc_hmac_init(TCHmacState_t ctx);
/**
* @brief HMAC update procedure
* Mixes data_length bytes addressed by data into state
* @return returns TC_SUCCCESS (1)
* returns TC_FAIL (0) if: ctx == NULL or key == NULL
* @note Assumes state has been initialized by tc_hmac_init
* @param ctx IN/OUT -- state of HMAC computation so far
* @param data IN -- data to incorporate into state
* @param data_length IN -- size of data in bytes
*/
int32_t tc_hmac_update(TCHmacState_t ctx, const void *data, uint32_t data_length);
/**
* @brief HMAC final procedure
* Writes the HMAC tag into the tag buffer
* @return returns TC_SUCCESS (1)
* returns TC_FAIL (0) if:
* tag == NULL or
* ctx == NULL or
* key == NULL or
* taglen != TC_SHA256_DIGEST_SIZE
* @note Assumes the tag bufer is at least sizeof(hmac_tag_size(state)) bytes
* state has been initialized by tc_hmac_init
* @param tag IN/OUT -- buffer to receive computed HMAC tag
* @param taglen IN -- size of tag in bytes
* @param ctx IN -- the HMAC state for computing tag
*/
int32_t tc_hmac_final(uint8_t *tag, uint32_t taglen, TCHmacState_t ctx);
#endif
|
