SIGBYTES
sigbuf = xmalloc(msglen + SIGBYTES);
memcpy(sig, sigbuf, SIGBYTES);
siglen = SIGBYTES + msglen;
memcpy(sigbuf, sig->sig, SIGBYTES);
memcpy(sigbuf + SIGBYTES, msg, msglen);
uint8_t sig[SIGBYTES];