Random Number Generation functions

Utility functions for generating random data. More...

Collaboration diagram for Random Number Generation functions:

Functions
void	RAND_GetBytes (uint16_t aNumBytes, void *aBytesOut)
	Get random data for non-cryptographic purposes. More...
void	RAND_Seed (uint64_t aSeed)
	Seed the non-cryptographic Pseudo Random Number Generator. More...
void	RAND_SeedFromDev (struct ca821x_dev *pDeviceRef)
	Seed the non-cryptographic Pseudo Random Number Generator using entropy from the ca821x. More...
ca_error	RAND_GetCryptoBytes (uint16_t aNumBytes, void *aBytesOut)
	Get random data for cryptographic purposes. More...
void	RAND_AddRadioEntropySource (void)
	Add the radio-based RNG as an entropy source used by mbedTLS. More...

Detailed Description

Utility functions for generating random data.

Function Documentation

RAND_AddRadioEntropySource()

void RAND_AddRadioEntropySource

(

void

)

Add the radio-based RNG as an entropy source used by mbedTLS.

RAND_GetBytes()

void RAND_GetBytes	(	uint16_t	aNumBytes,
		void *	aBytesOut
	)

Get random data for non-cryptographic purposes.

This function will never fail.

Depending on the platform this may be from a PRNG. Will fill memory starting from address aBytesOut with aNumBytes of pseudorandom random data. This data will be uniformly distributed, but not suitable for cryptographic purposes as the sequence can be predicted.

Parameters

	aNumBytes	The number of bytes to fill with random data
[out]	aBytesOut	The start address to fill with random data

RAND_GetCryptoBytes()

ca_error RAND_GetCryptoBytes	(	uint16_t	aNumBytes,
		void *	aBytesOut
	)

Get random data for cryptographic purposes.

This function will use a CPRNG, and be suitable for cryptographic purposes. Will fill memory starting from address aBytesOut with aNumBytes of random data. Upon an error, the output memory will be left in an indeterminate state and should not be relied upon to be random data, or be in its previous state.

Parameters

	aNumBytes	The number of bytes to fill with random data
[out]	aBytesOut	The start address to fill with random data

Returns

Cascoda Error code

Return values

CA_ERROR_SUCCESS	Success, aBytesOut is filled with aNumBytes of random data.
CA_ERROR_FAIL	Request failed, aBytesOut is indeterminate

RAND_Seed()

void RAND_Seed

(

uint64_t

aSeed

)

Seed the non-cryptographic Pseudo Random Number Generator.

It is required to call either this or RAND_SeedFromDev before using RAND_GetBytes or the sequence will be the same for different devices. This is handled within the initialisation functions for each platform.

Parameters

aSeed

A seed for the PRNG. Should be unique, such as a random number or Unix time.

RAND_SeedFromDev()

void RAND_SeedFromDev

(

struct ca821x_dev *

pDeviceRef

)

Seed the non-cryptographic Pseudo Random Number Generator using entropy from the ca821x.

It is required to call either this or RAND_Seed before using RAND_GetBytes or the sequence will be the same for different devices. This is handled within the initialisation functions for each platform.

Parameters

pDeviceRef

The CA821x device to use to source the entropy