common/mbedtls/havege.h

   1 /**
   2  * \file havege.h
   3  *
   4  * \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion
   5  */
   6 /*
   7  *  Copyright The Mbed TLS Contributors
   8  *  SPDX-License-Identifier: Apache-2.0
   9  *
  10  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
  11  *  not use this file except in compliance with the License.
  12  *  You may obtain a copy of the License at
  13  *
  14  *  http://www.apache.org/licenses/LICENSE-2.0
  15  *
  16  *  Unless required by applicable law or agreed to in writing, software
  17  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  18  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  19  *  See the License for the specific language governing permissions and
  20  *  limitations under the License.
  21  */
  22 #ifndef MBEDTLS_HAVEGE_H
  23 #define MBEDTLS_HAVEGE_H
  24
  25 #if !defined(MBEDTLS_CONFIG_FILE)
  26 #include "mbedtls/config.h"
  27 #else
  28 #include MBEDTLS_CONFIG_FILE
  29 #endif
  30
  31 #include <stddef.h>
  32 #include <stdint.h>
  33
  34 #define MBEDTLS_HAVEGE_COLLECT_SIZE 1024
  35
  36 #ifdef __cplusplus
  37 extern "C" {
  38 #endif
  39
  40 /**
  41  * \brief          HAVEGE state structure
  42  */
  43 typedef struct mbedtls_havege_state {
  44     uint32_t PT1, PT2, offset[2];
  45     uint32_t pool[MBEDTLS_HAVEGE_COLLECT_SIZE];
  46     uint32_t WALK[8192];
  47 }
  48 mbedtls_havege_state;
  49
  50 /**
  51  * \brief          HAVEGE initialization
  52  *
  53  * \param hs       HAVEGE state to be initialized
  54  */
  55 void mbedtls_havege_init(mbedtls_havege_state *hs);
  56
  57 /**
  58  * \brief          Clear HAVEGE state
  59  *
  60  * \param hs       HAVEGE state to be cleared
  61  */
  62 void mbedtls_havege_free(mbedtls_havege_state *hs);
  63
  64 /**
  65  * \brief          HAVEGE rand function
  66  *
  67  * \param p_rng    A HAVEGE state
  68  * \param output   Buffer to fill
  69  * \param len      Length of buffer
  70  *
  71  * \return         0
  72  */
  73 int mbedtls_havege_random(void *p_rng, unsigned char *output, size_t len);
  74
  75 #ifdef __cplusplus
  76 }
  77 #endif
  78
  79 #endif /* havege.h */