/* * ECDH params to be used with kpp API * * 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_ECDH_ #define _CRYPTO_ECDH_ /** * DOC: ECDH Helper Functions * * To use ECDH with the KPP cipher API, the following data structure and * functions should be used. * * The ECC curves known to the ECDH implementation are specified in this * header file. * * To use ECDH with KPP, the following functions should be used to operate on * an ECDH private key. The packet private key that can be set with * the KPP API function call of crypto_kpp_set_secret. */ /* Curves IDs */ #define ECC_CURVE_NIST_P192 0x0001 #define ECC_CURVE_NIST_P256 0x0002 /** * struct ecdh - define an ECDH private key * * @curve_id: ECC curve the key is based on. * @key: Private ECDH key * @key_size: Size of the private ECDH key */ struct ecdh { unsigned short curve_id; char *key; unsigned short key_size; }; /** * crypto_ecdh_key_len() - Obtain the size of the private ECDH key * @params: private ECDH key * * This function returns the packet ECDH key size. A caller can use that * with the provided ECDH private key reference to obtain the required * memory size to hold a packet key. * * Return: size of the key in bytes */ unsigned int crypto_ecdh_key_len(const struct ecdh *params); /** * crypto_ecdh_encode_key() - encode the private key * @buf: Buffer allocated by the caller to hold the packet ECDH * private key. The buffer should be at least crypto_ecdh_key_len * bytes in size. * @len: Length of the packet private key buffer * @p: Buffer with the caller-specified private key * * The ECDH implementations operate on a packet representation of the private * key. * * Return: -EINVAL if buffer has insufficient size, 0 on success */ int crypto_ecdh_encode_key(char *buf, unsigned int len, const struct ecdh *p); /** * crypto_ecdh_decode_key() - decode a private key * @buf: Buffer holding a packet key that should be decoded * @len: Length of the packet private key buffer * @p: Buffer allocated by the caller that is filled with the * unpacked ECDH 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_ecdh_decode_key(const char *buf, unsigned int len, struct ecdh *p); #endif