| /** |
| * \file hkdf.h |
| * |
| * \brief This file contains the HKDF interface. |
| * |
| * The HMAC-based Extract-and-Expand Key Derivation Function (HKDF) is |
| * specified by RFC 5869. |
| */ |
| /* |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later |
| * |
| * This file is provided under the Apache License 2.0, or the |
| * GNU General Public License v2.0 or later. |
| * |
| * ********** |
| * Apache License 2.0: |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| * ********** |
| * |
| * ********** |
| * GNU General Public License v2.0 or later: |
| * |
| * 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. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * ********** |
| */ |
| #ifndef MBEDTLS_HKDF_H |
| #define MBEDTLS_HKDF_H |
| |
| #if !defined(MBEDTLS_CONFIG_FILE) |
| #include "config.h" |
| #else |
| #include MBEDTLS_CONFIG_FILE |
| #endif |
| |
| #include "md.h" |
| |
| /** |
| * \name HKDF Error codes |
| * \{ |
| */ |
| /** Bad input parameters to function. */ |
| #define MBEDTLS_ERR_HKDF_BAD_INPUT_DATA -0x5F80 |
| /* \} name */ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** |
| * \brief This is the HMAC-based Extract-and-Expand Key Derivation Function |
| * (HKDF). |
| * |
| * \param md A hash function; md.size denotes the length of the hash |
| * function output in bytes. |
| * \param salt An optional salt value (a non-secret random value); |
| * if the salt is not provided, a string of all zeros of |
| * md.size length is used as the salt. |
| * \param salt_len The length in bytes of the optional \p salt. |
| * \param ikm The input keying material. |
| * \param ikm_len The length in bytes of \p ikm. |
| * \param info An optional context and application specific information |
| * string. This can be a zero-length string. |
| * \param info_len The length of \p info in bytes. |
| * \param okm The output keying material of \p okm_len bytes. |
| * \param okm_len The length of the output keying material in bytes. This |
| * must be less than or equal to 255 * md.size bytes. |
| * |
| * \return 0 on success. |
| * \return #MBEDTLS_ERR_HKDF_BAD_INPUT_DATA when the parameters are invalid. |
| * \return An MBEDTLS_ERR_MD_* error for errors returned from the underlying |
| * MD layer. |
| */ |
| int mbedtls_hkdf( const mbedtls_md_info_t *md, const unsigned char *salt, |
| size_t salt_len, const unsigned char *ikm, size_t ikm_len, |
| const unsigned char *info, size_t info_len, |
| unsigned char *okm, size_t okm_len ); |
| |
| /** |
| * \brief Take the input keying material \p ikm and extract from it a |
| * fixed-length pseudorandom key \p prk. |
| * |
| * \warning This function should only be used if the security of it has been |
| * studied and established in that particular context (eg. TLS 1.3 |
| * key schedule). For standard HKDF security guarantees use |
| * \c mbedtls_hkdf instead. |
| * |
| * \param md A hash function; md.size denotes the length of the |
| * hash function output in bytes. |
| * \param salt An optional salt value (a non-secret random value); |
| * if the salt is not provided, a string of all zeros |
| * of md.size length is used as the salt. |
| * \param salt_len The length in bytes of the optional \p salt. |
| * \param ikm The input keying material. |
| * \param ikm_len The length in bytes of \p ikm. |
| * \param[out] prk A pseudorandom key of at least md.size bytes. |
| * |
| * \return 0 on success. |
| * \return #MBEDTLS_ERR_HKDF_BAD_INPUT_DATA when the parameters are invalid. |
| * \return An MBEDTLS_ERR_MD_* error for errors returned from the underlying |
| * MD layer. |
| */ |
| int mbedtls_hkdf_extract( const mbedtls_md_info_t *md, |
| const unsigned char *salt, size_t salt_len, |
| const unsigned char *ikm, size_t ikm_len, |
| unsigned char *prk ); |
| |
| /** |
| * \brief Expand the supplied \p prk into several additional pseudorandom |
| * keys, which is the output of the HKDF. |
| * |
| * \warning This function should only be used if the security of it has been |
| * studied and established in that particular context (eg. TLS 1.3 |
| * key schedule). For standard HKDF security guarantees use |
| * \c mbedtls_hkdf instead. |
| * |
| * \param md A hash function; md.size denotes the length of the hash |
| * function output in bytes. |
| * \param prk A pseudorandom key of at least md.size bytes. \p prk is |
| * usually the output from the HKDF extract step. |
| * \param prk_len The length in bytes of \p prk. |
| * \param info An optional context and application specific information |
| * string. This can be a zero-length string. |
| * \param info_len The length of \p info in bytes. |
| * \param okm The output keying material of \p okm_len bytes. |
| * \param okm_len The length of the output keying material in bytes. This |
| * must be less than or equal to 255 * md.size bytes. |
| * |
| * \return 0 on success. |
| * \return #MBEDTLS_ERR_HKDF_BAD_INPUT_DATA when the parameters are invalid. |
| * \return An MBEDTLS_ERR_MD_* error for errors returned from the underlying |
| * MD layer. |
| */ |
| int mbedtls_hkdf_expand( const mbedtls_md_info_t *md, const unsigned char *prk, |
| size_t prk_len, const unsigned char *info, |
| size_t info_len, unsigned char *okm, size_t okm_len ); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* hkdf.h */ |