1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2 | /* |
3 | * ECDH params to be used with kpp API |
4 | * |
5 | * Copyright (c) 2016, Intel Corporation |
6 | * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com> |
7 | */ |
8 | #ifndef _CRYPTO_ECDH_ |
9 | #define _CRYPTO_ECDH_ |
10 | |
11 | /** |
12 | * DOC: ECDH Helper Functions |
13 | * |
14 | * To use ECDH with the KPP cipher API, the following data structure and |
15 | * functions should be used. |
16 | * |
17 | * The ECC curves known to the ECDH implementation are specified in this |
18 | * header file. |
19 | * |
20 | * To use ECDH with KPP, the following functions should be used to operate on |
21 | * an ECDH private key. The packet private key that can be set with |
22 | * the KPP API function call of crypto_kpp_set_secret. |
23 | */ |
24 | |
25 | /* Curves IDs */ |
26 | #define ECC_CURVE_NIST_P192 0x0001 |
27 | #define ECC_CURVE_NIST_P256 0x0002 |
28 | #define ECC_CURVE_NIST_P384 0x0003 |
29 | |
30 | /** |
31 | * struct ecdh - define an ECDH private key |
32 | * |
33 | * @key: Private ECDH key |
34 | * @key_size: Size of the private ECDH key |
35 | */ |
36 | struct ecdh { |
37 | char *key; |
38 | unsigned short key_size; |
39 | }; |
40 | |
41 | /** |
42 | * crypto_ecdh_key_len() - Obtain the size of the private ECDH key |
43 | * @params: private ECDH key |
44 | * |
45 | * This function returns the packet ECDH key size. A caller can use that |
46 | * with the provided ECDH 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_ecdh_key_len(const struct ecdh *params); |
52 | |
53 | /** |
54 | * crypto_ecdh_encode_key() - encode the private key |
55 | * @buf: Buffer allocated by the caller to hold the packet ECDH |
56 | * private key. The buffer should be at least crypto_ecdh_key_len |
57 | * bytes in size. |
58 | * @len: Length of the packet private key buffer |
59 | * @p: Buffer with the caller-specified private key |
60 | * |
61 | * The ECDH 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_ecdh_encode_key(char *buf, unsigned int len, const struct ecdh *p); |
67 | |
68 | /** |
69 | * crypto_ecdh_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 | * @p: Buffer allocated by the caller that is filled with the |
73 | * unpacked ECDH 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_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p); |
81 | |
82 | #endif |
83 | |