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
29/**
30 * struct ecdh - define an ECDH private key
31 *
32 * @curve_id:	ECC curve the key is based on.
33 * @key:	Private ECDH key
34 * @key_size:	Size of the private ECDH key
35 */
36struct ecdh {
37	unsigned short curve_id;
38	char *key;
39	unsigned short key_size;
40};
41
42/**
43 * crypto_ecdh_key_len() - Obtain the size of the private ECDH key
44 * @params:	private ECDH key
45 *
46 * This function returns the packet ECDH key size. A caller can use that
47 * with the provided ECDH private key reference to obtain the required
48 * memory size to hold a packet key.
49 *
50 * Return: size of the key in bytes
51 */
52unsigned int crypto_ecdh_key_len(const struct ecdh *params);
53
54/**
55 * crypto_ecdh_encode_key() - encode the private key
56 * @buf:	Buffer allocated by the caller to hold the packet ECDH
57 *		private key. The buffer should be at least crypto_ecdh_key_len
58 *		bytes in size.
59 * @len:	Length of the packet private key buffer
60 * @p:		Buffer with the caller-specified private key
61 *
62 * The ECDH implementations operate on a packet representation of the private
63 * key.
64 *
65 * Return:	-EINVAL if buffer has insufficient size, 0 on success
66 */
67int crypto_ecdh_encode_key(char *buf, unsigned int len, const struct ecdh *p);
68
69/**
70 * crypto_ecdh_decode_key() - decode a private key
71 * @buf:	Buffer holding a packet key that should be decoded
72 * @len:	Length of the packet private key buffer
73 * @p:		Buffer allocated by the caller that is filled with the
74 *		unpacked ECDH private key.
75 *
76 * The unpacking obtains the private key by pointing @p to the correct location
77 * in @buf. Thus, both pointers refer to the same memory.
78 *
79 * Return:	-EINVAL if buffer has insufficient size, 0 on success
80 */
81int crypto_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p);
82
83#endif

 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 */
36struct 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 */
51unsigned 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 */
66int 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 */
80int crypto_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p);
81
82#endif