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