lcx_rng.h

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Random Number Generation. More...

Typedefs
typedef uint32_t(*	cx_rng_u32_range_randfunc_t) (void)

Functions
void	cx_rng_no_throw (uint8_t *buffer, size_t len)
	Generates a random buffer such that each byte is between 0 and 255. More...
static unsigned char *	cx_rng (uint8_t *buffer, size_t len)
	Generates a random buffer such that each byte is between 0 and 255. More...
static uint32_t	cx_rng_u32 (void)
	Returns 32 random bits. More...
static uint8_t	cx_rng_u8 (void)
	Returns 8 random bits. More...
uint32_t	cx_rng_u32_range_func (uint32_t a, uint32_t b, cx_rng_u32_range_randfunc_t randfunc)
	Generates a random 32-bit unsigned integer with a specified function. More...
static uint32_t	cx_rng_u32_range (uint32_t a, uint32_t b)
	Generates a random 32-bit unsigned integer. More...
cx_err_t	cx_rng_rfc6979 (cx_md_t hash_id, const uint8_t *x, size_t x_len, const uint8_t *h1, size_t h1_len, const uint8_t *q, size_t q_len, uint8_t *out, size_t out_len)
	Generates a random buffer according to RFC6979 . More...

Detailed Description

Random Number Generation.

Random numbers with different sizes can be generated: a 8-bit random number, a 32-bit random number or a random number of arbitrary size. In this case, the number is returned as a buffer of random bytes. The random number can also be generated within a specific range.

Typedef Documentation

cx_rng_u32_range_randfunc_t

typedef uint32_t(* cx_rng_u32_range_randfunc_t) (void)

Function Documentation

cx_rng()

static unsigned char* cx_rng ( uint8_t *  buffer, size_t  len  )

Generates a random buffer such that each byte is between 0 and 255.

Parameters

[out]	buffer	Buffer to hold the random data.
[in]	len	Length of the buffer i.e. number of random bytes to put into the buffer.

Returns

Pointer to the buffer.

cx_rng_no_throw()

void cx_rng_no_throw	(	uint8_t *	buffer,
		size_t	len
)

Generates a random buffer such that each byte is between 0 and 255.

Parameters

[out]	buffer	Buffer to hold the random data.
[in]	len	Length of the buffer i.e. number of random bytes to put into the buffer.

cx_rng_rfc6979()

cx_err_t cx_rng_rfc6979	(	cx_md_t	hash_id,
		const uint8_t *	x,
		size_t	x_len,
		const uint8_t *	h1,
		size_t	h1_len,
		const uint8_t *	q,
		size_t	q_len,
		uint8_t *	out,
		size_t	out_len
)

Generates a random buffer according to RFC6979 .

Parameters

[in]	hash_id	Message digest algorithm identifier.
[in]	x	ECDSA private key.
[in]	x_len	Length of the key.
[in]	h1	Hash of the message.
[in]	h1_len	Length of the hash.
[in]	q	Prime number that is a divisor of the curve order.
[in]	q_len	Length of the prime number q.
[out]	out	Buffer for the output.
[in]	out_len	Length of the output.

Returns

Error code:

• CX_OK on success
• CX_INVALID_PARAMETER

cx_rng_u32()

static uint32_t cx_rng_u32 ( void  )

Returns 32 random bits.

Returns

A 32-bit random number.

cx_rng_u32_range()

static uint32_t cx_rng_u32_range ( uint32_t  a, uint32_t  b  )

Generates a random 32-bit unsigned integer.

The generated number is taken in the range [a;b[ with uniform distribution.

Parameters

[in]	a	Inclusive low bound.
[in]	b	Exclusive high bound.

Returns

A 32-bit random number.

cx_rng_u32_range_func()

uint32_t cx_rng_u32_range_func	(	uint32_t	a,
		uint32_t	b,
		cx_rng_u32_range_randfunc_t	randfunc
)

Generates a random 32-bit unsigned integer with a specified function.

The generated number is taken in the range [a;b[ with uniform distribution.

Parameters

[in]	a	Inclusive low bound.
[in]	b	Exclusive high bound.
[in]	randfunc	Function called to generate the random value.

Returns

A 32-bit random number.

cx_rng_u8()

static uint8_t cx_rng_u8 ( void  )

Returns 8 random bits.

Returns

A 8-bit random number.

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