1.47 CRYPT_HMAC_DataAdd Function

C

int CRYPT_HMAC_DataAdd(
    CRYPT_HMAC_CTX* hmac,
    const unsigned char* input,
    unsigned int sz
);

Description

This function adds data to the HMAC so that multiple blocks of data can be processed.

Preconditions

The CRYPT_HMAC_CTX context must be initialized using the CRYPT_HMAC_SetKey function prior to any call to this function.

Parameters

ParametersDescription
hmacPointer to context that saves state between calls
inputPointer to the data that will be used to update the hash
szSize of the input data in bytes

Returns

  • BAD_FUNC_ARG - An invalid pointer was passed to the function
  • 0 - An invalid pointer was not passed to the function

Remarks

None.

Example

CRYPT_HMAC_CTX mcHmac;
byte           mcDigest[CRYPT_SHA512_DIGEST_SIZE];

CRYPT_HMAC_SetKey(&mcHmac, CRYPT_HMAC_SHA, key, 4);
CRYPT_HMAC_DataAdd(&mcHmac, ourData, OUR_DATA_SIZE);
CRYPT_HMAC_Finalize(&mcHmac, mcDigest);