1/*
2 * Copyright (c) 2013, Kenneth MacKay
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
15 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
16 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
17 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
18 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
19 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
20 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26#ifndef _CRYPTO_ECC_H
27#define _CRYPTO_ECC_H
28
29#define ECC_CURVE_NIST_P192_DIGITS 3
30#define ECC_CURVE_NIST_P256_DIGITS 4
31#define ECC_MAX_DIGITS ECC_CURVE_NIST_P256_DIGITS
32
33#define ECC_DIGITS_TO_BYTES_SHIFT 3
34
35/**
36 * ecc_is_key_valid() - Validate a given ECDH private key
37 *
38 * @curve_id: id representing the curve to use
39 * @ndigits: curve's number of digits
40 * @private_key: private key to be used for the given curve
41 * @private_key_len: private key length
42 *
43 * Returns 0 if the key is acceptable, a negative value otherwise
44 */
45int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
46 const u64 *private_key, unsigned int private_key_len);
47
48/**
49 * ecc_gen_privkey() - Generates an ECC private key.
50 * The private key is a random integer in the range 0 < random < n, where n is a
51 * prime that is the order of the cyclic subgroup generated by the distinguished
52 * point G.
53 * @curve_id: id representing the curve to use
54 * @ndigits: curve number of digits
55 * @private_key: buffer for storing the generated private key
56 *
57 * Returns 0 if the private key was generated successfully, a negative value
58 * if an error occurred.
59 */
60int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey);
61
62/**
63 * ecc_make_pub_key() - Compute an ECC public key
64 *
65 * @curve_id: id representing the curve to use
66 * @ndigits: curve's number of digits
67 * @private_key: pregenerated private key for the given curve
68 * @public_key: buffer for storing the generated public key
69 *
70 * Returns 0 if the public key was generated successfully, a negative value
71 * if an error occurred.
72 */
73int ecc_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
74 const u64 *private_key, u64 *public_key);
75
76/**
77 * crypto_ecdh_shared_secret() - Compute a shared secret
78 *
79 * @curve_id: id representing the curve to use
80 * @ndigits: curve's number of digits
81 * @private_key: private key of part A
82 * @public_key: public key of counterpart B
83 * @secret: buffer for storing the calculated shared secret
84 *
85 * Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
86 * before using it for symmetric encryption or HMAC.
87 *
88 * Returns 0 if the shared secret was generated successfully, a negative value
89 * if an error occurred.
90 */
91int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
92 const u64 *private_key, const u64 *public_key,
93 u64 *secret);
94#endif
95