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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
802c7f1c SB |
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> | |
802c7f1c SB |
7 | */ |
8 | #ifndef _CRYPTO_DH_ | |
9 | #define _CRYPTO_DH_ | |
10 | ||
8d23da22 SM |
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 | */ | |
802c7f1c | 32 | struct dh { |
215bebc8 NS |
33 | const void *key; |
34 | const void *p; | |
35 | const void *g; | |
802c7f1c SB |
36 | unsigned int key_size; |
37 | unsigned int p_size; | |
38 | unsigned int g_size; | |
39 | }; | |
40 | ||
8d23da22 SM |
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 | */ | |
5b3f3a8b | 51 | unsigned int crypto_dh_key_len(const struct dh *params); |
8d23da22 SM |
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 | */ | |
802c7f1c | 66 | int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params); |
8d23da22 SM |
67 | |
68 | /** | |
69 | * crypto_dh_decode_key() - decode a private key | |
70 | * @buf: Buffer holding a packet key that should be decoded | |
c0ca1215 | 71 | * @len: Length of the packet private key buffer |
8d23da22 | 72 | * @params: Buffer allocated by the caller that is filled with the |
c0ca1215 | 73 | * unpacked DH private key. |
8d23da22 SM |
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 | */ | |
802c7f1c SB |
80 | int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params); |
81 | ||
fae19893 NS |
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 | ||
802c7f1c | 98 | #endif |