Algorithm - SipHash

Functions
int	wc_InitSipHash (SipHash *siphash, const unsigned char *key, unsigned char outSz)
	This function initializes SipHash with a key for a MAC size. More...
int	wc_SipHashUpdate (SipHash *siphash, const unsigned char *in, word32 inSz)
	Can be called to continually hash the provided byte array of length len. More...
int	wc_SipHashFinal (SipHash *siphash, unsigned char *out, unsigned char outSz)
	Finalizes MACing of data. Result is placed into out. More...
int	wc_SipHash (const unsigned char *key, const unsigned char *in, word32 inSz, unsigned char *out, unsigned char outSz)
	This function one-shots the data using SipHash to calculate a MAC based on the key. More...

Detailed Description

Function Documentation

wc_InitSipHash()

int wc_InitSipHash	(	SipHash *	siphash,
		const unsigned char *	key,
		unsigned char	outSz
	)

This function initializes SipHash with a key for a MAC size.

Returns

0 Returned upon successfully initializing

BAD_FUNC_ARG Returned when siphash or key is NULL

BAD_FUNC_ARG Returned when outSz is neither 8 nor 16

Parameters

siphash	pointer to the SipHash structure to use for MACing
key	pointer to the 16-byte array
outSz	number of bytes to output as MAC

Example

SipHash siphash[1];
unsigned char key[16] = { ... };
byte macSz = 8; // 8 or 16
 
if ((ret = wc_InitSipHash(siphash, key, macSz)) != 0) {
    WOLFSSL_MSG("wc_InitSipHash failed");
}
else if ((ret = wc_SipHashUpdate(siphash, data, len)) != 0) {
    WOLFSSL_MSG("wc_SipHashUpdate failed");
}
else if ((ret = wc_SipHashFinal(siphash, mac, macSz)) != 0) {
    WOLFSSL_MSG("wc_SipHashFinal failed");
}

See also

wc_SipHash

wc_SipHashUpdate

wc_SipHashFinal

wc_SipHash()

int wc_SipHash	(	const unsigned char *	key,
		const unsigned char *	in,
		word32	inSz,
		unsigned char *	out,
		unsigned char	outSz
	)

This function one-shots the data using SipHash to calculate a MAC based on the key.

Returns

0 Returned upon successfully MACing

BAD_FUNC_ARG Returned when key or out is NULL

BAD_FUNC_ARG Returned when in is NULL and inSz is not zero

BAD_FUNC_ARG Returned when outSz is neither 8 nor 16

Parameters

key	pointer to the 16-byte array
in	the data to be MACed
inSz	size of data to be MACed
out	Byte array to hold MAC value
outSz	number of bytes to output as MAC

Example

unsigned char key[16] = { ... };
byte data[] = { Data to be MACed };
word32 len = sizeof(data);
byte mac[8] = { ... }; // 8 or 16 bytes
byte macSz = sizeof(mac);
 
if ((ret = wc_SipHash(key, data, len, mac, macSz)) != 0) {
    WOLFSSL_MSG("wc_SipHash failed");
}

See also

wc_InitSipHash

wc_SipHashUpdate

wc_SipHashFinal

wc_SipHashFinal()

int wc_SipHashFinal	(	SipHash *	siphash,
		unsigned char *	out,
		unsigned char	outSz
	)

Finalizes MACing of data. Result is placed into out.

Returns

0 Returned upon successfully finalizing.

BAD_FUNC_ARG Returned when siphash of out is NULL

BAD_FUNC_ARG Returned when outSz is not the same as the initialized value

Parameters

siphash	pointer to the SipHash structure to use for MACing
out	Byte array to hold MAC value
outSz	number of bytes to output as MAC

Example

SipHash siphash[1];
byte mac[8] = { ... }; // 8 or 16 bytes
byte macSz = sizeof(mac);
 
if ((ret = wc_InitSipHash(siphash, key, macSz)) != 0) {
    WOLFSSL_MSG("wc_InitSipHash failed");
}
else if ((ret = wc_SipHashUpdate(siphash, data, len)) != 0) {
    WOLFSSL_MSG("wc_SipHashUpdate failed");
}
else if ((ret = wc_SipHashFinal(siphash, mac, macSz)) != 0) {
    WOLFSSL_MSG("wc_SipHashFinal failed");
}

See also

wc_SipHash

wc_InitSipHash

wc_SipHashUpdate

wc_SipHashUpdate()

int wc_SipHashUpdate	(	SipHash *	siphash,
		const unsigned char *	in,
		word32	inSz
	)

Can be called to continually hash the provided byte array of length len.

Returns

0 Returned upon successfully adding the data to the MAC

BAD_FUNC_ARG Returned when siphash is NULL

BAD_FUNC_ARG Returned when in is NULL and inSz is not zero

Parameters

siphash	pointer to the SipHash structure to use for MACing
in	the data to be MACed
inSz	size of data to be MACed

Example

SipHash siphash[1];
byte data[] = { Data to be MACed };
word32 len = sizeof(data);
 
if ((ret = wc_InitSipHash(siphash, key, macSz)) != 0) {
    WOLFSSL_MSG("wc_InitSipHash failed");
}
else if ((ret = wc_SipHashUpdate(siphash, data, len)) != 0) {
    WOLFSSL_MSG("wc_SipHashUpdate failed");
}
else if ((ret = wc_SipHashFinal(siphash, mac, macSz)) != 0) {
    WOLFSSL_MSG("wc_SipHashFinal failed");
}

See also

wc_SipHash

wc_InitSipHash

wc_SipHashFinal