OPTIGA Trust M  1.1.0
C++ library for Optiga Trust M Chip Security Controller
entropy.h File Reference

Entropy accumulator implementation. More...

#include "config.h"
#include <stddef.h>
#include "sha256.h"
Include dependency graph for entropy.h:

Go to the source code of this file.

Classes

struct  mbedtls_entropy_source_state
 Entropy source state. More...
 
struct  mbedtls_entropy_context
 Entropy context structure. More...
 

Macros

#define MBEDTLS_ENTROPY_SHA256_ACCUMULATOR
 
#define MBEDTLS_ERR_ENTROPY_SOURCE_FAILED   -0x003C
 
#define MBEDTLS_ERR_ENTROPY_MAX_SOURCES   -0x003E
 
#define MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED   -0x0040
 
#define MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE   -0x003D
 
#define MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR   -0x003F
 
#define MBEDTLS_ENTROPY_BLOCK_SIZE   32
 
#define MBEDTLS_ENTROPY_MAX_SEED_SIZE   1024
 
#define MBEDTLS_ENTROPY_SOURCE_MANUAL   MBEDTLS_ENTROPY_MAX_SOURCES
 
#define MBEDTLS_ENTROPY_SOURCE_STRONG   1
 
#define MBEDTLS_ENTROPY_SOURCE_WEAK   0
 
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_ENTROPY_MAX_SOURCES   20
 
#define MBEDTLS_ENTROPY_MAX_GATHER   128
 

Typedefs

typedef int(* mbedtls_entropy_f_source_ptr) (void *data, unsigned char *output, size_t len, size_t *olen)
 Entropy poll callback pointer. More...
 
typedef struct mbedtls_entropy_source_state mbedtls_entropy_source_state
 Entropy source state. More...
 
typedef struct mbedtls_entropy_context mbedtls_entropy_context
 Entropy context structure. More...
 

Functions

void mbedtls_entropy_init (mbedtls_entropy_context *ctx)
 Initialize the context. More...
 
void mbedtls_entropy_free (mbedtls_entropy_context *ctx)
 Free the data in the context. More...
 
int mbedtls_entropy_add_source (mbedtls_entropy_context *ctx, mbedtls_entropy_f_source_ptr f_source, void *p_source, size_t threshold, int strong)
 Adds an entropy source to poll (Thread-safe if MBEDTLS_THREADING_C is enabled) More...
 
int mbedtls_entropy_gather (mbedtls_entropy_context *ctx)
 Trigger an extra gather poll for the accumulator (Thread-safe if MBEDTLS_THREADING_C is enabled) More...
 
int mbedtls_entropy_func (void *data, unsigned char *output, size_t len)
 Retrieve entropy from the accumulator (Maximum length: MBEDTLS_ENTROPY_BLOCK_SIZE) (Thread-safe if MBEDTLS_THREADING_C is enabled) More...
 
int mbedtls_entropy_update_manual (mbedtls_entropy_context *ctx, const unsigned char *data, size_t len)
 Add data to the accumulator manually (Thread-safe if MBEDTLS_THREADING_C is enabled) More...
 

Detailed Description

Entropy accumulator implementation.

Macro Definition Documentation

◆ MBEDTLS_ENTROPY_BLOCK_SIZE

#define MBEDTLS_ENTROPY_BLOCK_SIZE   32

Block size of entropy accumulator (SHA-256)

◆ MBEDTLS_ENTROPY_MAX_GATHER

#define MBEDTLS_ENTROPY_MAX_GATHER   128

Maximum amount requested from entropy sources

◆ MBEDTLS_ENTROPY_MAX_SEED_SIZE

#define MBEDTLS_ENTROPY_MAX_SEED_SIZE   1024

Maximum size of seed we read from seed file

◆ MBEDTLS_ENTROPY_MAX_SOURCES

#define MBEDTLS_ENTROPY_MAX_SOURCES   20

Maximum number of sources supported

◆ MBEDTLS_ENTROPY_SHA256_ACCUMULATOR

#define MBEDTLS_ENTROPY_SHA256_ACCUMULATOR

◆ MBEDTLS_ENTROPY_SOURCE_MANUAL

#define MBEDTLS_ENTROPY_SOURCE_MANUAL   MBEDTLS_ENTROPY_MAX_SOURCES

◆ MBEDTLS_ENTROPY_SOURCE_STRONG

#define MBEDTLS_ENTROPY_SOURCE_STRONG   1

Entropy source is strong

◆ MBEDTLS_ENTROPY_SOURCE_WEAK

#define MBEDTLS_ENTROPY_SOURCE_WEAK   0

Entropy source is weak

◆ MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR

#define MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR   -0x003F

Read/write error in file.

◆ MBEDTLS_ERR_ENTROPY_MAX_SOURCES

#define MBEDTLS_ERR_ENTROPY_MAX_SOURCES   -0x003E

No more sources can be added.

◆ MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED

#define MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED   -0x0040

No sources have been added to poll.

◆ MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE

#define MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE   -0x003D

No strong sources have been added to poll.

◆ MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

#define MBEDTLS_ERR_ENTROPY_SOURCE_FAILED   -0x003C

Critical entropy source failure.

Typedef Documentation

◆ mbedtls_entropy_context

Entropy context structure.

◆ mbedtls_entropy_f_source_ptr

typedef int(* mbedtls_entropy_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, MBEDTLS_ERR_ENTROPY_SOURCE_FAILED otherwise

◆ mbedtls_entropy_source_state

Entropy source state.

Function Documentation

◆ mbedtls_entropy_add_source()

int mbedtls_entropy_add_source ( mbedtls_entropy_context ctx,
mbedtls_entropy_f_source_ptr  f_source,
void *  p_source,
size_t  threshold,
int  strong 
)

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

Parameters
ctxEntropy context
f_sourceEntropy function
p_sourceFunction data
thresholdMinimum required from source before entropy is released ( with mbedtls_entropy_func() ) (in bytes)
strongMBEDTLS_ENTROPY_SOURCE_STRONG or MBEDTLS_ENTROPY_SOURCE_WEAK. At least one strong source needs to be added. Weaker sources (such as the cycle counter) can be used as a complement.
Returns
0 if successful or MBEDTLS_ERR_ENTROPY_MAX_SOURCES

◆ mbedtls_entropy_free()

void mbedtls_entropy_free ( mbedtls_entropy_context ctx)

Free the data in the context.

Parameters
ctxEntropy context to free

◆ mbedtls_entropy_func()

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

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

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

◆ mbedtls_entropy_gather()

int mbedtls_entropy_gather ( mbedtls_entropy_context ctx)

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

Parameters
ctxEntropy context
Returns
0 if successful, or MBEDTLS_ERR_ENTROPY_SOURCE_FAILED

◆ mbedtls_entropy_init()

void mbedtls_entropy_init ( mbedtls_entropy_context ctx)

Initialize the context.

Parameters
ctxEntropy context to initialize

◆ mbedtls_entropy_update_manual()

int mbedtls_entropy_update_manual ( mbedtls_entropy_context ctx,
const unsigned char *  data,
size_t  len 
)

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

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