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_MAX_DIGITS	4 /* 256 */
30
31#define ECC_DIGITS_TO_BYTES_SHIFT 3
32
33/**
34 * ecc_is_key_valid() - Validate a given ECDH private key
35 *
36 * @curve_id:		id representing the curve to use
37 * @ndigits:		curve number of digits
38 * @private_key:	private key to be used for the given curve
39 * @private_key_len:	private key len
40 *
41 * Returns 0 if the key is acceptable, a negative value otherwise
42 */
43int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
44		     const u8 *private_key, unsigned int private_key_len);
45
46/**
47 * ecdh_make_pub_key() - Compute an ECC public key
48 *
49 * @curve_id:		id representing the curve to use
50 * @private_key:	pregenerated private key for the given curve
51 * @private_key_len:	length of private_key
52 * @public_key:		buffer for storing the public key generated
53 * @public_key_len:	length of the public_key buffer
54 *
55 * Returns 0 if the public key was generated successfully, a negative value
56 * if an error occurred.
57 */
58int ecdh_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
59		      const u8 *private_key, unsigned int private_key_len,
60		      u8 *public_key, unsigned int public_key_len);
61
62/**
63 * crypto_ecdh_shared_secret() - Compute a shared secret
64 *
65 * @curve_id:		id representing the curve to use
66 * @private_key:	private key of part A
67 * @private_key_len:	length of private_key
68 * @public_key:		public key of counterpart B
69 * @public_key_len:	length of public_key
70 * @secret:		buffer for storing the calculated shared secret
71 * @secret_len:		length of the secret buffer
72 *
73 * Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
74 * before using it for symmetric encryption or HMAC.
75 *
76 * Returns 0 if the shared secret was generated successfully, a negative value
77 * if an error occurred.
78 */
79int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
80		       const u8 *private_key, unsigned int private_key_len,
81		       const u8 *public_key, unsigned int public_key_len,
82		       u8 *secret, unsigned int secret_len);
83#endif