/* SPDX-License-Identifier: GPL-2.0-or-later *//* * Diffie-Hellman secret to be used with kpp API along with helper functions * * Copyright (c) 2016, Intel Corporation * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com> */#ifndef _CRYPTO_DH_#define _CRYPTO_DH_ /** * DOC: DH Helper Functions * * To use DH with the KPP cipher API, the following data structure and * functions should be used. * * To use DH with KPP, the following functions should be used to operate on * a DH private key. The packet private key that can be set with * the KPP API function call of crypto_kpp_set_secret. */ /** * struct dh - define a DH private key * * @key:	Private DH key * @p:		Diffie-Hellman parameter P * @g:		Diffie-Hellman generator G * @key_size:	Size of the private DH key * @p_size:	Size of DH parameter P * @g_size:	Size of DH generator G */struct dh {	const void *key;	const void *p;	const void *g;	unsigned int key_size;	unsigned int p_size;	unsigned int g_size;}; /** * crypto_dh_key_len() - Obtain the size of the private DH key * @params:	private DH key * * This function returns the packet DH key size. A caller can use that * with the provided DH private key reference to obtain the required * memory size to hold a packet key. * * Return: size of the key in bytes */unsigned int crypto_dh_key_len(const struct dh *params); /** * crypto_dh_encode_key() - encode the private key * @buf:	Buffer allocated by the caller to hold the packet DH *		private key. The buffer should be at least crypto_dh_key_len *		bytes in size. * @len:	Length of the packet private key buffer * @params:	Buffer with the caller-specified private key * * The DH implementations operate on a packet representation of the private * key. * * Return:	-EINVAL if buffer has insufficient size, 0 on success */int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params); /** * crypto_dh_decode_key() - decode a private key * @buf:	Buffer holding a packet key that should be decoded * @len:	Length of the packet private key buffer * @params:	Buffer allocated by the caller that is filled with the *		unpacked DH private key. * * The unpacking obtains the private key by pointing @p to the correct location * in @buf. Thus, both pointers refer to the same memory. * * Return:	-EINVAL if buffer has insufficient size, 0 on success */int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params); /** * __crypto_dh_decode_key() - decode a private key without parameter checks * @buf:	Buffer holding a packet key that should be decoded * @len:	Length of the packet private key buffer * @params:	Buffer allocated by the caller that is filled with the *		unpacked DH private key. * * Internal function providing the same services as the exported * crypto_dh_decode_key(), but without any of those basic parameter * checks conducted by the latter. * * Return:	-EINVAL if buffer has insufficient size, 0 on success */int __crypto_dh_decode_key(const char *buf, unsigned int len,			   struct dh *params); #endif