CRYPT_HMAC_SetKey Function

C

int CRYPT_HMAC_SetKey(
    CRYPT_HMAC_CTX* hmac, 
    int type, 
    const unsigned char* key, 
    unsigned int sz
);

Description

This function initializes the HMAC context and sets the key for the hash.

Preconditions

None.

Parameters

Parameters	Description
hmac	Pointer to context that saves state between calls.
type	Type of SHA operation to use with HMAC. Must be one of the following: CRYPT_HMAC_SHA, CRYPT_HMAC_SHA256, CRYPT_HMAC_SHA384, or CRYPT_HMAC_SHA512
key	Secret key used for the hash.
sz	Size 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);