sip24_update
return sip24_final(sip24_update(sip24_init(&state, key), src, len));
sip24_update(&sip_state, b->uri, b->uriLen * sizeof(XML_Char));
sip24_update(&sip_state, s, keylen(s) * sizeof(XML_Char));
sip24_update(&state, s, keylen(s) * sizeof(XML_Char));
sip24_update(&state, message, 4);
sip24_update(&state, message + 4, len - 4);
sip24_update(&state, message, 0);