mbed TLS v1.3.19
Data Structures | Macros | Functions
ctr_drbg.h File Reference

CTR_DRBG based on AES-256 (NIST SP 800-90) More...

#include "aes.h"
Include dependency graph for ctr_drbg.h:

Go to the source code of this file.

Data Structures

struct  ctr_drbg_context
 CTR_DRBG context structure. More...
 

Macros

#define POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED   -0x0034
 The entropy source failed. More...
 
#define POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG   -0x0036
 Too many random requested in single call. More...
 
#define POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG   -0x0038
 Input too large (Entropy + additional). More...
 
#define POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR   -0x003A
 Read/write error in file. More...
 
#define CTR_DRBG_BLOCKSIZE   16
 Block size used by the cipher. More...
 
#define CTR_DRBG_KEYSIZE   32
 Key size used by the cipher. More...
 
#define CTR_DRBG_KEYBITS   ( CTR_DRBG_KEYSIZE * 8 )
 
#define CTR_DRBG_SEEDLEN   ( CTR_DRBG_KEYSIZE + CTR_DRBG_BLOCKSIZE )
 The seed length (counter + AES key) More...
 
#define CTR_DRBG_PR_OFF   0
 No prediction resistance. More...
 
#define CTR_DRBG_PR_ON   1
 Prediction resistance enabled. More...
 
SECTION: Module settings

The configuration options you can set for this module are in this section.

Either change them in config.h or define them on the compiler command line.

#define CTR_DRBG_ENTROPY_LEN   48
 Amount of entropy used per seed by default (48 with SHA-512, 32 with SHA-256) More...
 
#define CTR_DRBG_RESEED_INTERVAL   10000
 Interval before reseed is performed by default. More...
 
#define CTR_DRBG_MAX_INPUT   256
 Maximum number of additional input bytes. More...
 
#define CTR_DRBG_MAX_REQUEST   1024
 Maximum number of requested bytes per call. More...
 
#define CTR_DRBG_MAX_SEED_INPUT   384
 Maximum size of (re)seed buffer. More...
 

Functions

int ctr_drbg_init (ctr_drbg_context *ctx, int(*f_entropy)(void *, unsigned char *, size_t), void *p_entropy, const unsigned char *custom, size_t len)
 CTR_DRBG initialization. More...
 
void ctr_drbg_free (ctr_drbg_context *ctx)
 Clear CTR_CRBG context data. More...
 
void ctr_drbg_set_prediction_resistance (ctr_drbg_context *ctx, int resistance)
 Enable / disable prediction resistance (Default: Off) More...
 
void ctr_drbg_set_entropy_len (ctr_drbg_context *ctx, size_t len)
 Set the amount of entropy grabbed on each (re)seed (Default: CTR_DRBG_ENTROPY_LEN) More...
 
void ctr_drbg_set_reseed_interval (ctr_drbg_context *ctx, int interval)
 Set the reseed interval (Default: CTR_DRBG_RESEED_INTERVAL) More...
 
int ctr_drbg_reseed (ctr_drbg_context *ctx, const unsigned char *additional, size_t len)
 CTR_DRBG reseeding (extracts data from entropy source) More...
 
void ctr_drbg_update (ctr_drbg_context *ctx, const unsigned char *additional, size_t add_len)
 CTR_DRBG update state. More...
 
int ctr_drbg_random_with_add (void *p_rng, unsigned char *output, size_t output_len, const unsigned char *additional, size_t add_len)
 CTR_DRBG generate random with additional update input. More...
 
int ctr_drbg_random (void *p_rng, unsigned char *output, size_t output_len)
 CTR_DRBG generate random. More...
 
int ctr_drbg_write_seed_file (ctr_drbg_context *ctx, const char *path)
 Write a seed file. More...
 
int ctr_drbg_update_seed_file (ctr_drbg_context *ctx, const char *path)
 Read and update a seed file. More...
 
int ctr_drbg_self_test (int verbose)
 Checkup routine. More...
 
int ctr_drbg_init_entropy_len (ctr_drbg_context *, int(*)(void *, unsigned char *, size_t), void *, const unsigned char *, size_t, size_t)
 

Detailed Description

CTR_DRBG based on AES-256 (NIST SP 800-90)

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 ctr_drbg.h.

Macro Definition Documentation

#define CTR_DRBG_BLOCKSIZE   16

Block size used by the cipher.

Definition at line 34 of file ctr_drbg.h.

#define CTR_DRBG_ENTROPY_LEN   48

Amount of entropy used per seed by default (48 with SHA-512, 32 with SHA-256)

Definition at line 50 of file ctr_drbg.h.

#define CTR_DRBG_KEYBITS   ( CTR_DRBG_KEYSIZE * 8 )

Definition at line 36 of file ctr_drbg.h.

#define CTR_DRBG_KEYSIZE   32

Key size used by the cipher.

Definition at line 35 of file ctr_drbg.h.

#define CTR_DRBG_MAX_INPUT   256

Maximum number of additional input bytes.

Definition at line 61 of file ctr_drbg.h.

#define CTR_DRBG_MAX_REQUEST   1024

Maximum number of requested bytes per call.

Definition at line 65 of file ctr_drbg.h.

#define CTR_DRBG_MAX_SEED_INPUT   384

Maximum size of (re)seed buffer.

Definition at line 69 of file ctr_drbg.h.

#define CTR_DRBG_PR_OFF   0

No prediction resistance.

Definition at line 74 of file ctr_drbg.h.

#define CTR_DRBG_PR_ON   1

Prediction resistance enabled.

Definition at line 75 of file ctr_drbg.h.

#define CTR_DRBG_RESEED_INTERVAL   10000

Interval before reseed is performed by default.

Definition at line 57 of file ctr_drbg.h.

#define CTR_DRBG_SEEDLEN   ( CTR_DRBG_KEYSIZE + CTR_DRBG_BLOCKSIZE )

The seed length (counter + AES key)

Definition at line 37 of file ctr_drbg.h.

#define POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED   -0x0034

The entropy source failed.

Definition at line 29 of file ctr_drbg.h.

#define POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR   -0x003A

Read/write error in file.

Definition at line 32 of file ctr_drbg.h.

#define POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG   -0x0038

Input too large (Entropy + additional).

Definition at line 31 of file ctr_drbg.h.

#define POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG   -0x0036

Too many random requested in single call.

Definition at line 30 of file ctr_drbg.h.

Function Documentation

void ctr_drbg_free ( ctr_drbg_context ctx)

Clear CTR_CRBG context data.

Parameters
ctxCTR_DRBG context to clear
int ctr_drbg_init ( ctr_drbg_context ctx,
int(*)(void *, unsigned char *, size_t)  f_entropy,
void *  p_entropy,
const unsigned char *  custom,
size_t  len 
)

CTR_DRBG initialization.

Note: Personalization data can be provided in addition to the more generic entropy source to make this instantiation as unique as possible.

Parameters
ctxCTR_DRBG context to be initialized
f_entropyEntropy callback (p_entropy, buffer to fill, buffer length)
p_entropyEntropy context
customPersonalization data (Device specific identifiers) (Can be NULL)
lenLength of personalization data
Returns
0 if successful, or POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED
int ctr_drbg_init_entropy_len ( ctr_drbg_context ,
int(*)(void *, unsigned char *, size_t)  ,
void *  ,
const unsigned char *  ,
size_t  ,
size_t   
)
int ctr_drbg_random ( void *  p_rng,
unsigned char *  output,
size_t  output_len 
)

CTR_DRBG generate random.

Note: Automatically reseeds if reseed_counter is reached.

Parameters
p_rngCTR_DRBG context
outputBuffer to fill
output_lenLength of the buffer
Returns
0 if successful, or POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED, or POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG
int ctr_drbg_random_with_add ( void *  p_rng,
unsigned char *  output,
size_t  output_len,
const unsigned char *  additional,
size_t  add_len 
)

CTR_DRBG generate random with additional update input.

Note: Automatically reseeds if reseed_counter is reached.

Parameters
p_rngCTR_DRBG context
outputBuffer to fill
output_lenLength of the buffer
additionalAdditional data to update with (Can be NULL)
add_lenLength of additional data
Returns
0 if successful, or POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED, or POLARSSL_ERR_CTR_DRBG_REQUEST_TOO_BIG
int ctr_drbg_reseed ( ctr_drbg_context ctx,
const unsigned char *  additional,
size_t  len 
)

CTR_DRBG reseeding (extracts data from entropy source)

Parameters
ctxCTR_DRBG context
additionalAdditional data to add to state (Can be NULL)
lenLength of additional data
Returns
0 if successful, or POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED
int ctr_drbg_self_test ( int  verbose)

Checkup routine.

Returns
0 if successful, or 1 if the test failed
void ctr_drbg_set_entropy_len ( ctr_drbg_context ctx,
size_t  len 
)

Set the amount of entropy grabbed on each (re)seed (Default: CTR_DRBG_ENTROPY_LEN)

Parameters
ctxCTR_DRBG context
lenAmount of entropy to grab
void ctr_drbg_set_prediction_resistance ( ctr_drbg_context ctx,
int  resistance 
)

Enable / disable prediction resistance (Default: Off)

Note: If enabled, entropy is used for ctx->entropy_len before each call! Only use this if you have ample supply of good entropy!

Parameters
ctxCTR_DRBG context
resistanceCTR_DRBG_PR_ON or CTR_DRBG_PR_OFF
void ctr_drbg_set_reseed_interval ( ctr_drbg_context ctx,
int  interval 
)

Set the reseed interval (Default: CTR_DRBG_RESEED_INTERVAL)

Parameters
ctxCTR_DRBG context
intervalReseed interval
void ctr_drbg_update ( ctr_drbg_context ctx,
const unsigned char *  additional,
size_t  add_len 
)

CTR_DRBG update state.

Parameters
ctxCTR_DRBG context
additionalAdditional data to update state with
add_lenLength of additional data
Note
If add_len is greater than CTR_DRBG_MAX_SEED_INPUT, only the first CTR_DRBG_MAX_SEED_INPUT bytes are used, the remaining ones are silently discarded.
int ctr_drbg_update_seed_file ( ctr_drbg_context ctx,
const char *  path 
)

Read and update a seed file.

Seed is added to this instance

Parameters
ctxCTR_DRBG context
pathName of the file
Returns
0 if successful, POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR on file error, POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED or POLARSSL_ERR_CTR_DRBG_INPUT_TOO_BIG
int ctr_drbg_write_seed_file ( ctr_drbg_context ctx,
const char *  path 
)

Write a seed file.

Parameters
ctxCTR_DRBG context
pathName of the file
Returns
0 if successful, POLARSSL_ERR_CTR_DRBG_FILE_IO_ERROR on file error, or POLARSSL_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED