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 OR GPL-2.0-or-later
9  *
10  *  This file is provided under the Apache License 2.0, or the
11  *  GNU General Public License v2.0 or later.
12  *
13  *  **********
14  *  Apache License 2.0:
15  *
16  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
17  *  not use this file except in compliance with the License.
18  *  You may obtain a copy of the License at
19  *
20  *  http://www.apache.org/licenses/LICENSE-2.0
21  *
22  *  Unless required by applicable law or agreed to in writing, software
23  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
24  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25  *  See the License for the specific language governing permissions and
26  *  limitations under the License.
27  *
28  *  **********
29  *
30  *  **********
31  *  GNU General Public License v2.0 or later:
32  *
33  *  This program is free software; you can redistribute it and/or modify
34  *  it under the terms of the GNU General Public License as published by
35  *  the Free Software Foundation; either version 2 of the License, or
36  *  (at your option) any later version.
37  *
38  *  This program is distributed in the hope that it will be useful,
39  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
40  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
41  *  GNU General Public License for more details.
42  *
43  *  You should have received a copy of the GNU General Public License along
44  *  with this program; if not, write to the Free Software Foundation, Inc.,
45  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
46  *
47  *  **********
48  */
49 #ifndef MBEDTLS_HAVEGE_H
50 #define MBEDTLS_HAVEGE_H
51 
52 #if !defined(MBEDTLS_CONFIG_FILE)
53 #include "config.h"
54 #else
55 #include MBEDTLS_CONFIG_FILE
56 #endif
57 
58 #include <stddef.h>
59 
60 #define MBEDTLS_HAVEGE_COLLECT_SIZE 1024
61 
62 #ifdef __cplusplus
63 extern "C" {
64 #endif
65 
66 /**
67  * \brief          HAVEGE state structure
68  */
69 typedef struct mbedtls_havege_state
70 {
71     int PT1, PT2, offset[2];
72     int pool[MBEDTLS_HAVEGE_COLLECT_SIZE];
73     int WALK[8192];
74 }
75 mbedtls_havege_state;
76 
77 /**
78  * \brief          HAVEGE initialization
79  *
80  * \param hs       HAVEGE state to be initialized
81  */
82 void mbedtls_havege_init( mbedtls_havege_state *hs );
83 
84 /**
85  * \brief          Clear HAVEGE state
86  *
87  * \param hs       HAVEGE state to be cleared
88  */
89 void mbedtls_havege_free( mbedtls_havege_state *hs );
90 
91 /**
92  * \brief          HAVEGE rand function
93  *
94  * \param p_rng    A HAVEGE state
95  * \param output   Buffer to fill
96  * \param len      Length of buffer
97  *
98  * \return         0
99  */
100 int mbedtls_havege_random( void *p_rng, unsigned char *output, size_t len );
101 
102 #ifdef __cplusplus
103 }
104 #endif
105 
106 #endif /* havege.h */
107