void sc_read(FILE *file, char *buf, size_t *len, int *end);
void sc_send(FILE *file, char *buf, size_t *len);
char sc_key(char *hash, uint32_t *cnum);
void sc_work(char *ibuf, size_t *ilen, char *obuf, size_t *olen, char *hash, uint32_t *cnum);
void main_loop(char *key, FILE *in, FILE *out);