hmac_drbg.h File Reference

HMAC_DRBG (NIST SP 800-90A) More...

#include "md.h"

Include dependency graph for hmac_drbg.h:

Go to the source code of this file.

Classes
struct	mbedtls_hmac_drbg_context

Macros
#define	MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG   -0x0003
#define	MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG   -0x0005
#define	MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR   -0x0007
#define	MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED   -0x0009
#define	MBEDTLS_HMAC_DRBG_PR_OFF   0
#define	MBEDTLS_HMAC_DRBG_PR_ON   1
#define	MBEDTLS_DEPRECATED
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	MBEDTLS_HMAC_DRBG_RESEED_INTERVAL   10000
#define	MBEDTLS_HMAC_DRBG_MAX_INPUT   256
#define	MBEDTLS_HMAC_DRBG_MAX_REQUEST   1024
#define	MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT   384

Typedefs
typedef struct mbedtls_hmac_drbg_context	mbedtls_hmac_drbg_context

Functions
void	mbedtls_hmac_drbg_init (mbedtls_hmac_drbg_context *ctx)
	HMAC_DRBG context initialization Makes the context ready for mbedtls_hmac_drbg_seed(), mbedtls_hmac_drbg_seed_buf() or mbedtls_hmac_drbg_free(). More...
int	mbedtls_hmac_drbg_seed (mbedtls_hmac_drbg_context *ctx, const mbedtls_md_info_t *md_info, int(*f_entropy)(void *, unsigned char *, size_t), void *p_entropy, const unsigned char *custom, size_t len)
	HMAC_DRBG initial seeding Seed and setup entropy source for future reseeds. More...
int	mbedtls_hmac_drbg_seed_buf (mbedtls_hmac_drbg_context *ctx, const mbedtls_md_info_t *md_info, const unsigned char *data, size_t data_len)
	Initilisation of simpified HMAC_DRBG (never reseeds). (For use with deterministic ECDSA.) More...
void	mbedtls_hmac_drbg_set_prediction_resistance (mbedtls_hmac_drbg_context *ctx, int resistance)
	Enable / disable prediction resistance (Default: Off) More...
void	mbedtls_hmac_drbg_set_entropy_len (mbedtls_hmac_drbg_context *ctx, size_t len)
	Set the amount of entropy grabbed on each reseed (Default: given by the security strength, which depends on the hash used, see mbedtls_hmac_drbg_init() ) More...
void	mbedtls_hmac_drbg_set_reseed_interval (mbedtls_hmac_drbg_context *ctx, int interval)
	Set the reseed interval (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL) More...
int	mbedtls_hmac_drbg_update_ret (mbedtls_hmac_drbg_context *ctx, const unsigned char *additional, size_t add_len)
	HMAC_DRBG update state. More...
int	mbedtls_hmac_drbg_reseed (mbedtls_hmac_drbg_context *ctx, const unsigned char *additional, size_t len)
	HMAC_DRBG reseeding (extracts data from entropy source) More...
int	mbedtls_hmac_drbg_random_with_add (void *p_rng, unsigned char *output, size_t output_len, const unsigned char *additional, size_t add_len)
	HMAC_DRBG generate random with additional update input. More...
int	mbedtls_hmac_drbg_random (void *p_rng, unsigned char *output, size_t out_len)
	HMAC_DRBG generate random. More...
void	mbedtls_hmac_drbg_free (mbedtls_hmac_drbg_context *ctx)
	Free an HMAC_DRBG context. More...
MBEDTLS_DEPRECATED void	mbedtls_hmac_drbg_update (mbedtls_hmac_drbg_context *ctx, const unsigned char *additional, size_t add_len)
	HMAC_DRBG update state. More...

Detailed Description

HMAC_DRBG (NIST SP 800-90A)

Macro Definition Documentation

MBEDTLS_DEPRECATED

#define MBEDTLS_DEPRECATED

MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED

#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED   -0x0009

The entropy source failed.

MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR

#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR   -0x0007

Read/write error in file.

MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG

#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG   -0x0005

Input too large (Entropy + additional).

MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG

#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG   -0x0003

Too many random requested in single call.

MBEDTLS_HMAC_DRBG_MAX_INPUT

#define MBEDTLS_HMAC_DRBG_MAX_INPUT   256

Maximum number of additional input bytes

MBEDTLS_HMAC_DRBG_MAX_REQUEST

#define MBEDTLS_HMAC_DRBG_MAX_REQUEST   1024

Maximum number of requested bytes per call

MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT

#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT   384

Maximum size of (re)seed buffer

MBEDTLS_HMAC_DRBG_PR_OFF

#define MBEDTLS_HMAC_DRBG_PR_OFF   0

No prediction resistance

MBEDTLS_HMAC_DRBG_PR_ON

#define MBEDTLS_HMAC_DRBG_PR_ON   1

Prediction resistance enabled

MBEDTLS_HMAC_DRBG_RESEED_INTERVAL

#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL   10000

Interval before reseed is performed by default

Typedef Documentation

mbedtls_hmac_drbg_context

typedef struct mbedtls_hmac_drbg_context mbedtls_hmac_drbg_context

HMAC_DRBG context.

Function Documentation

mbedtls_hmac_drbg_free()

void mbedtls_hmac_drbg_free

(

mbedtls_hmac_drbg_context *

ctx

)

Free an HMAC_DRBG context.

Parameters

ctx	HMAC_DRBG context to free.

mbedtls_hmac_drbg_init()

void mbedtls_hmac_drbg_init

(

mbedtls_hmac_drbg_context *

ctx

)

HMAC_DRBG context initialization Makes the context ready for mbedtls_hmac_drbg_seed(), mbedtls_hmac_drbg_seed_buf() or mbedtls_hmac_drbg_free().

Parameters

ctx	HMAC_DRBG context to be initialized

mbedtls_hmac_drbg_random()

int mbedtls_hmac_drbg_random	(	void *	p_rng,
		unsigned char *	output,
		size_t	out_len
	)

HMAC_DRBG generate random.

Note: Automatically reseeds if reseed_counter is reached or PR is enabled.

Parameters

p_rng	HMAC_DRBG context
output	Buffer to fill
out_len	Length of the buffer

Returns

0 if successful, or MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG

mbedtls_hmac_drbg_random_with_add()

int mbedtls_hmac_drbg_random_with_add	(	void *	p_rng,
		unsigned char *	output,
		size_t	output_len,
		const unsigned char *	additional,
		size_t	add_len
	)

HMAC_DRBG generate random with additional update input.

Note: Automatically reseeds if reseed_counter is reached or PR is enabled.

Parameters

p_rng	HMAC_DRBG context
output	Buffer to fill
output_len	Length of the buffer
additional	Additional data to update with (can be NULL)
add_len	Length of additional data (can be 0)

Returns

0 if successful, or MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG.

mbedtls_hmac_drbg_reseed()

int mbedtls_hmac_drbg_reseed	(	mbedtls_hmac_drbg_context *	ctx,
		const unsigned char *	additional,
		size_t	len
	)

HMAC_DRBG reseeding (extracts data from entropy source)

Parameters

ctx	HMAC_DRBG context
additional	Additional data to add to state (Can be NULL)
len	Length of additional data

Returns

0 if successful, or MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED

mbedtls_hmac_drbg_seed()

int mbedtls_hmac_drbg_seed	(	mbedtls_hmac_drbg_context *	ctx,
		const mbedtls_md_info_t *	md_info,
		int(*)(void *, unsigned char *, size_t)	f_entropy,
		void *	p_entropy,
		const unsigned char *	custom,
		size_t	len
	)

HMAC_DRBG initial seeding Seed and setup entropy source for future reseeds.

Parameters

ctx	HMAC_DRBG context to be seeded
md_info	MD algorithm to use for HMAC_DRBG
f_entropy	Entropy callback (p_entropy, buffer to fill, buffer length)
p_entropy	Entropy context
custom	Personalization data (Device specific identifiers) (Can be NULL)
len	Length of personalization data

Note

The "security strength" as defined by NIST is set to: 128 bits if md_alg is SHA-1, 192 bits if md_alg is SHA-224, 256 bits if md_alg is SHA-256 or higher. Note that SHA-256 is just as efficient as SHA-224.

Returns

0 if successful, or MBEDTLS_ERR_MD_BAD_INPUT_DATA, or MBEDTLS_ERR_MD_ALLOC_FAILED, or MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED.

mbedtls_hmac_drbg_seed_buf()

int mbedtls_hmac_drbg_seed_buf	(	mbedtls_hmac_drbg_context *	ctx,
		const mbedtls_md_info_t *	md_info,
		const unsigned char *	data,
		size_t	data_len
	)

Initilisation of simpified HMAC_DRBG (never reseeds). (For use with deterministic ECDSA.)

Parameters

ctx	HMAC_DRBG context to be initialised
md_info	MD algorithm to use for HMAC_DRBG
data	Concatenation of entropy string and additional data
data_len	Length of data in bytes

Returns

0 if successful, or MBEDTLS_ERR_MD_BAD_INPUT_DATA, or MBEDTLS_ERR_MD_ALLOC_FAILED.

mbedtls_hmac_drbg_set_entropy_len()

void mbedtls_hmac_drbg_set_entropy_len	(	mbedtls_hmac_drbg_context *	ctx,
		size_t	len
	)

Set the amount of entropy grabbed on each reseed (Default: given by the security strength, which depends on the hash used, see mbedtls_hmac_drbg_init() )

Parameters

ctx	HMAC_DRBG context
len	Amount of entropy to grab, in bytes

mbedtls_hmac_drbg_set_prediction_resistance()

void mbedtls_hmac_drbg_set_prediction_resistance	(	mbedtls_hmac_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

ctx	HMAC_DRBG context
resistance	MBEDTLS_HMAC_DRBG_PR_ON or MBEDTLS_HMAC_DRBG_PR_OFF

mbedtls_hmac_drbg_set_reseed_interval()

void mbedtls_hmac_drbg_set_reseed_interval	(	mbedtls_hmac_drbg_context *	ctx,
		int	interval
	)

Set the reseed interval (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)

Parameters

ctx	HMAC_DRBG context
interval	Reseed interval

mbedtls_hmac_drbg_update()

MBEDTLS_DEPRECATED void mbedtls_hmac_drbg_update	(	mbedtls_hmac_drbg_context *	ctx,
		const unsigned char *	additional,
		size_t	add_len
	)

HMAC_DRBG update state.

Deprecated:

Superseded by mbedtls_hmac_drbg_update_ret() in 2.16.0.

Parameters

ctx	HMAC_DRBG context
additional	Additional data to update state with, or NULL
add_len	Length of additional data, or 0

Note

Additional data is optional, pass NULL and 0 as second third argument if no additional data is being used.

mbedtls_hmac_drbg_update_ret()

int mbedtls_hmac_drbg_update_ret	(	mbedtls_hmac_drbg_context *	ctx,
		const unsigned char *	additional,
		size_t	add_len
	)

HMAC_DRBG update state.

Parameters

ctx	HMAC_DRBG context
additional	Additional data to update state with, or NULL
add_len	Length of additional data, or 0

Returns

0 on success, or an error from the underlying hash calculation.

Note

Additional data is optional, pass NULL and 0 as second third argument if no additional data is being used.