1 /* SPDX-License-Identifier: GPL-2.0-or-later * <<
2 /* 1 /*
3 * Diffie-Hellman secret to be used with kpp A 2 * Diffie-Hellman secret to be used with kpp API along with helper functions
4 * 3 *
5 * Copyright (c) 2016, Intel Corporation 4 * Copyright (c) 2016, Intel Corporation
6 * Authors: Salvatore Benedetto <salvatore.ben 5 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
>> 6 *
>> 7 * This program is free software; you can redistribute it and/or modify it
>> 8 * under the terms of the GNU General Public License as published by the Free
>> 9 * Software Foundation; either version 2 of the License, or (at your option)
>> 10 * any later version.
>> 11 *
7 */ 12 */
8 #ifndef _CRYPTO_DH_ 13 #ifndef _CRYPTO_DH_
9 #define _CRYPTO_DH_ 14 #define _CRYPTO_DH_
10 15
11 /** 16 /**
12 * DOC: DH Helper Functions 17 * DOC: DH Helper Functions
13 * 18 *
14 * To use DH with the KPP cipher API, the foll 19 * To use DH with the KPP cipher API, the following data structure and
15 * functions should be used. 20 * functions should be used.
16 * 21 *
17 * To use DH with KPP, the following functions 22 * To use DH with KPP, the following functions should be used to operate on
18 * a DH private key. The packet private key th 23 * a DH private key. The packet private key that can be set with
19 * the KPP API function call of crypto_kpp_set 24 * the KPP API function call of crypto_kpp_set_secret.
20 */ 25 */
21 26
22 /** 27 /**
23 * struct dh - define a DH private key 28 * struct dh - define a DH private key
24 * 29 *
25 * @key: Private DH key 30 * @key: Private DH key
26 * @p: Diffie-Hellman parameter P 31 * @p: Diffie-Hellman parameter P
27 * @g: Diffie-Hellman generator G 32 * @g: Diffie-Hellman generator G
28 * @key_size: Size of the private DH key 33 * @key_size: Size of the private DH key
29 * @p_size: Size of DH parameter P 34 * @p_size: Size of DH parameter P
30 * @g_size: Size of DH generator G 35 * @g_size: Size of DH generator G
31 */ 36 */
32 struct dh { 37 struct dh {
33 const void *key; !! 38 void *key;
34 const void *p; !! 39 void *p;
35 const void *g; !! 40 void *g;
36 unsigned int key_size; 41 unsigned int key_size;
37 unsigned int p_size; 42 unsigned int p_size;
38 unsigned int g_size; 43 unsigned int g_size;
39 }; 44 };
40 45
41 /** 46 /**
42 * crypto_dh_key_len() - Obtain the size of th 47 * crypto_dh_key_len() - Obtain the size of the private DH key
43 * @params: private DH key 48 * @params: private DH key
44 * 49 *
45 * This function returns the packet DH key siz 50 * This function returns the packet DH key size. A caller can use that
46 * with the provided DH private key reference 51 * with the provided DH private key reference to obtain the required
47 * memory size to hold a packet key. 52 * memory size to hold a packet key.
48 * 53 *
49 * Return: size of the key in bytes 54 * Return: size of the key in bytes
50 */ 55 */
51 unsigned int crypto_dh_key_len(const struct dh 56 unsigned int crypto_dh_key_len(const struct dh *params);
52 57
53 /** 58 /**
54 * crypto_dh_encode_key() - encode the private 59 * crypto_dh_encode_key() - encode the private key
55 * @buf: Buffer allocated by the caller 60 * @buf: Buffer allocated by the caller to hold the packet DH
56 * private key. The buffer should 61 * private key. The buffer should be at least crypto_dh_key_len
57 * bytes in size. 62 * bytes in size.
58 * @len: Length of the packet private k 63 * @len: Length of the packet private key buffer
59 * @params: Buffer with the caller-specifi 64 * @params: Buffer with the caller-specified private key
60 * 65 *
61 * The DH implementations operate on a packet 66 * The DH implementations operate on a packet representation of the private
62 * key. 67 * key.
63 * 68 *
64 * Return: -EINVAL if buffer has insuffic 69 * Return: -EINVAL if buffer has insufficient size, 0 on success
65 */ 70 */
66 int crypto_dh_encode_key(char *buf, unsigned i 71 int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params);
67 72
68 /** 73 /**
69 * crypto_dh_decode_key() - decode a private k 74 * crypto_dh_decode_key() - decode a private key
70 * @buf: Buffer holding a packet key th 75 * @buf: Buffer holding a packet key that should be decoded
71 * @len: Length of the packet private k 76 * @len: Length of the packet private key buffer
72 * @params: Buffer allocated by the caller 77 * @params: Buffer allocated by the caller that is filled with the
73 * unpacked DH private key. 78 * unpacked DH private key.
74 * 79 *
75 * The unpacking obtains the private key by po 80 * The unpacking obtains the private key by pointing @p to the correct location
76 * in @buf. Thus, both pointers refer to the s 81 * in @buf. Thus, both pointers refer to the same memory.
77 * 82 *
78 * Return: -EINVAL if buffer has insuffic 83 * Return: -EINVAL if buffer has insufficient size, 0 on success
79 */ 84 */
80 int crypto_dh_decode_key(const char *buf, unsi 85 int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params);
81 <<
82 /** <<
83 * __crypto_dh_decode_key() - decode a private <<
84 * @buf: Buffer holding a packet key th <<
85 * @len: Length of the packet private k <<
86 * @params: Buffer allocated by the caller <<
87 * unpacked DH private key. <<
88 * <<
89 * Internal function providing the same servic <<
90 * crypto_dh_decode_key(), but without any of <<
91 * checks conducted by the latter. <<
92 * <<
93 * Return: -EINVAL if buffer has insuffic <<
94 */ <<
95 int __crypto_dh_decode_key(const char *buf, un <<
96 struct dh *params); <<
97 86
98 #endif 87 #endif
99 88
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