eay_hmac_init
static caddr_t eay_hmac_init(vchar_t *, const EVP_MD *);
return eay_hmac_init(key, EVP_sha2_512());
return eay_hmac_init(key, EVP_sha2_384());
return eay_hmac_init(key, EVP_sha2_256());
return eay_hmac_init(key, EVP_sha1());
return eay_hmac_init(key, EVP_md5());