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entropy.h File Reference

entropy.h File Reference

Entropy accumulator implementation. More...

Go to the source code of this file.

Data Structures

struct  source_state
 Entropy source state. More...
struct  entropy_context
 Entropy context structure. More...

Typedefs

typedef int(* f_source_ptr )(void *data, unsigned char *output, size_t len, size_t *olen)
 Entropy poll callback pointer.

Functions

void entropy_init (entropy_context *ctx)
 Initialize the context.
void entropy_free (entropy_context *ctx)
 Free the data in the context.
int entropy_add_source (entropy_context *ctx, f_source_ptr f_source, void *p_source, size_t threshold)
 Adds an entropy source to poll (Thread-safe if POLARSSL_THREADING_C is enabled)
int entropy_gather (entropy_context *ctx)
 Trigger an extra gather poll for the accumulator (Thread-safe if POLARSSL_THREADING_C is enabled)
int entropy_func (void *data, unsigned char *output, size_t len)
 Retrieve entropy from the accumulator (Maximum length: ENTROPY_BLOCK_SIZE) (Thread-safe if POLARSSL_THREADING_C is enabled)
int entropy_update_manual (entropy_context *ctx, const unsigned char *data, size_t len)
 Add data to the accumulator manually (Thread-safe if POLARSSL_THREADING_C is enabled)
int entropy_write_seed_file (entropy_context *ctx, const char *path)
 Write a seed file.
int entropy_update_seed_file (entropy_context *ctx, const char *path)
 Read and update a seed file.
int entropy_self_test (int verbose)
 Checkup routine.

Detailed Description

Entropy accumulator implementation.

Copyright (C) 2006-2014, ARM Limited, All Rights Reserved

This file is part of mbed TLS (https://tls.mbed.org)

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.

Definition in file entropy.h.


Typedef Documentation

typedef int(* f_source_ptr)(void *data, unsigned char *output, size_t len, size_t *olen)

Entropy poll callback pointer.

Parameters:
dataCallback-specific data pointer
outputData to fill
lenMaximum size to provide
olenThe actual amount of bytes put into the buffer (Can be 0)
Returns:
0 if no critical failures occurred, POLARSSL_ERR_ENTROPY_SOURCE_FAILED otherwise

Definition at line 100 of file entropy.h.


Function Documentation

int entropy_add_source ( entropy_context ctx,
f_source_ptr  f_source,
void *  p_source,
size_t  threshold 
)

Adds an entropy source to poll (Thread-safe if POLARSSL_THREADING_C is enabled)

Parameters:
ctxEntropy context
f_sourceEntropy function
p_sourceFunction data
thresholdMinimum required from source before entropy is released ( with entropy_func() )
Returns:
0 if successful or POLARSSL_ERR_ENTROPY_MAX_SOURCES

Definition at line 103 of file entropy.c.

void entropy_free ( entropy_context ctx )

Free the data in the context.

Parameters:
ctxEntropy context to free

Definition at line 92 of file entropy.c.

int entropy_func ( void *  data,
unsigned char *  output,
size_t  len 
)

Retrieve entropy from the accumulator (Maximum length: ENTROPY_BLOCK_SIZE) (Thread-safe if POLARSSL_THREADING_C is enabled)

Parameters:
dataEntropy context
outputBuffer to fill
lenNumber of bytes desired, must be at most ENTROPY_BLOCK_SIZE
Returns:
0 if successful, or POLARSSL_ERR_ENTROPY_SOURCE_FAILED

Definition at line 251 of file entropy.c.

int entropy_gather ( entropy_context ctx )

Trigger an extra gather poll for the accumulator (Thread-safe if POLARSSL_THREADING_C is enabled)

Parameters:
ctxEntropy context
Returns:
0 if successful, or POLARSSL_ERR_ENTROPY_SOURCE_FAILED

Definition at line 232 of file entropy.c.

void entropy_init ( entropy_context ctx )

Initialize the context.

Parameters:
ctxEntropy context to initialize

Definition at line 60 of file entropy.c.

int entropy_self_test ( int  verbose )

Checkup routine.

Returns:
0 if successful, or 1 if a test failed

Definition at line 411 of file entropy.c.

int entropy_update_manual ( entropy_context ctx,
const unsigned char *  data,
size_t  len 
)

Add data to the accumulator manually (Thread-safe if POLARSSL_THREADING_C is enabled)

Parameters:
ctxEntropy context
dataData to add
lenLength of data
Returns:
0 if successful

Definition at line 172 of file entropy.c.

int entropy_update_seed_file ( entropy_context ctx,
const char *  path 
)

Read and update a seed file.

Seed is added to this instance. No more than ENTROPY_MAX_SEED_SIZE bytes are read from the seed file. The rest is ignored.

Parameters:
ctxEntropy context
pathName of the file
Returns:
0 if successful, POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error, POLARSSL_ERR_ENTROPY_SOURCE_FAILED

Definition at line 361 of file entropy.c.

int entropy_write_seed_file ( entropy_context ctx,
const char *  path 
)

Write a seed file.

Parameters:
ctxEntropy context
pathName of the file
Returns:
0 if successful, POLARSSL_ERR_ENTROPY_FILE_IO_ERROR on file error, or POLARSSL_ERR_ENTROPY_SOURCE_FAILED

Definition at line 336 of file entropy.c.