/* * 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> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. * */ #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 * @q: Diffie-Hellman parameter Q * @g: Diffie-Hellman generator G * @key_size: Size of the private DH key * @p_size: Size of DH parameter P * @q_size: Size of DH parameter Q * @g_size: Size of DH generator G */ struct dh { void *key; void *p; void *q; void *g; unsigned int key_size; unsigned int p_size; unsigned int q_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); #endif