Random generation

General Description

Random generation definitions.

Functions
ifx_se_status_t	ifx_se_generate_random (ifx_se_fih_ptr_t output, ifx_se_fih_t output_size, void *ctx)
	Generate random bytes. More...

Function Documentation

ifx_se_generate_random()

ifx_se_status_t ifx_se_generate_random	(	ifx_se_fih_ptr_t	output,
		ifx_se_fih_t	output_size,
		void *	ctx
	)

Generate random bytes.

Warning

This function can fail! Callers MUST check the return status and MUST NOT use the content of the output buffer if the return status is not IFX_SE_SUCCESS.

Note

To generate a key, use ifx_se_generate_key() instead.

Parameters

[out]	output	Output buffer for the generated data.
[in]	output_size	Number of bytes to generate and output.
[in]	ctx	The pointer to the SE syscall context that contain a special syscall data (IPC release callback etc).

Warning

The output buffer MUST be larger than output_size by at least IFX_CRC32_CRC_SIZE (4 bytes) to save the CRC32 value at the end of the data block

Return values

IFX_SE_SUCCESS
IFX_SE_ERROR_NOT_SUPPORTED
IFX_SE_ERROR_INSUFFICIENT_ENTROPY
IFX_SE_ERROR_INSUFFICIENT_MEMORY
IFX_SE_ERROR_COMMUNICATION_FAILURE
IFX_SE_ERROR_HARDWARE_FAILURE
IFX_SE_ERROR_CORRUPTION_DETECTED

Function Usage

 
    /* Amount of random data to generate */
    #define RANDOM_DATA_SIZE    32
 
    /* The output buffer MUST be larger than output_size by at least
       IFX_CRC32_CRC_SIZE (4 bytes) to save the CRC32 value at the end
       of the data block */
    uint8_t random_data[RANDOM_DATA_SIZE + IFX_CRC32_CRC_SIZE];
 
    ifx_se_status_t status;
    uint32_t crc32;
 
    /* Generate True Random number in a specified range */
    status = ifx_se_generate_random(ifx_se_fih_ptr_encode(random_data),
                                    ifx_se_fih_uint_encode(RANDOM_DATA_SIZE),
                                    IFX_SE_NULL_CTX);
 
    /* ... check for errors... */
    ifx_se_status_t status_success = IFX_SE_SUCCESS;
    if (!IFX_SE_STATUS_CHECK(status, status_success))
    {
        /* ... process random performing error... */
        return status;
    }
 
    memcpy(&crc32, random_data + RANDOM_DATA_SIZE, IFX_CRC32_CRC_SIZE);
    if (crc32 == IFX_CRC32_CALC(random_data, RANDOM_DATA_SIZE))
    {
        /* ... process random data integrity error... */
        return IFX_SE_SYSCALL_DATA_INVALID;
    }
 
    /* ... continue ... */