/*
* Copyright (c) 2013, Kenneth MacKay
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _CRYPTO_ECC_H
#define _CRYPTO_ECC_H
#define ECC_MAX_DIGITS 4 /* 256 */
#define ECC_DIGITS_TO_BYTES_SHIFT 3
/**
* ecc_is_key_valid() - Validate a given ECDH private key
*
* @curve_id: id representing the curve to use
* @ndigits: curve number of digits
* @private_key: private key to be used for the given curve
* @private_key_len: private key len
*
* Returns 0 if the key is acceptable, a negative value otherwise
*/
int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
const u8 *private_key, unsigned int private_key_len);
/**
* ecdh_make_pub_key() - Compute an ECC public key
*
* @curve_id: id representing the curve to use
* @private_key: pregenerated private key for the given curve
* @private_key_len: length of private_key
* @public_key: buffer for storing the public key generated
* @public_key_len: length of the public_key buffer
*
* Returns 0 if the public key was generated successfully, a negative value
* if an error occurred.
*/
int ecdh_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
const u8 *private_key, unsigned int private_key_len,
u8 *public_key, unsigned int public_key_len);
/**
* crypto_ecdh_shared_secret() - Compute a shared secret
*
* @curve_id: id representing the curve to use
* @private_key: private key of part A
* @private_key_len: length of private_key
* @public_key: public key of counterpart B
* @public_key_len: length of public_key
* @secret: buffer for storing the calculated shared secret
* @secret_len: length of the secret buffer
*
* Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
* before using it for symmetric encryption or HMAC.
*
* Returns 0 if the shared secret was generated successfully, a negative value
* if an error occurred.
*/
int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
const u8 *private_key, unsigned int private_key_len,
const u8 *public_key, unsigned int public_key_len,
u8 *secret, unsigned int secret_len);
#endif
