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Algorithm - SipHash

Functions

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

Functions Documentation

function 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.

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

See:

Return:

  • 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

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");
}

function 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.

Parameters:

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

See:

Return:

  • 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

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");
}

function wc_SipHashFinal

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

Finalizes MACing of data. Result is placed into out.

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

See:

Return:

  • 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

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");
}

function 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.

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

See:

Return:

  • 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

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");
}

Updated on 2024-11-21 at 01:17:07 +0000