havege.h

00001 /**
00002  * \file havege.h
00003  *
00004  * \brief HAVEGE: HArdware Volatile Entropy Gathering and Expansion
00005  *
00006  *  Copyright (C) 2006-2013, ARM Limited, All Rights Reserved
00007  *
00008  *  This file is part of mbed TLS (https://tls.mbed.org)
00009  *
00010  *  This program is free software; you can redistribute it and/or modify
00011  *  it under the terms of the GNU General Public License as published by
00012  *  the Free Software Foundation; either version 2 of the License, or
00013  *  (at your option) any later version.
00014  *
00015  *  This program is distributed in the hope that it will be useful,
00016  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00017  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00018  *  GNU General Public License for more details.
00019  *
00020  *  You should have received a copy of the GNU General Public License along
00021  *  with this program; if not, write to the Free Software Foundation, Inc.,
00022  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00023  */
00024 #ifndef POLARSSL_HAVEGE_H
00025 #define POLARSSL_HAVEGE_H
00026 
00027 #include <stddef.h>
00028 
00029 #define COLLECT_SIZE 1024
00030 
00031 #ifdef __cplusplus
00032 extern "C" {
00033 #endif
00034 
00035 /**
00036  * \brief          HAVEGE state structure
00037  */
00038 typedef struct
00039 {
00040     int PT1, PT2, offset[2];
00041     int pool[COLLECT_SIZE];
00042     int WALK[8192];
00043 }
00044 havege_state;
00045 
00046 /**
00047  * \brief          HAVEGE initialization
00048  *
00049  * \param hs       HAVEGE state to be initialized
00050  */
00051 void havege_init( havege_state *hs );
00052 
00053 /**
00054  * \brief          Clear HAVEGE state
00055  *
00056  * \param hs       HAVEGE state to be cleared
00057  */
00058 void havege_free( havege_state *hs );
00059 
00060 /**
00061  * \brief          HAVEGE rand function
00062  *
00063  * \param p_rng    A HAVEGE state
00064  * \param output   Buffer to fill
00065  * \param len      Length of buffer
00066  *
00067  * \return         0
00068  */
00069 int havege_random( void *p_rng, unsigned char *output, size_t len );
00070 
00071 #ifdef __cplusplus
00072 }
00073 #endif
00074 
00075 #endif /* havege.h */
00076