typedef struct d0_bignum_s d0_bignum_t;
-WARN_UNUSED_RESULT BOOL d0_iobuf_write_bignum(d0_iobuf_t *buf, const d0_bignum_t *bignum);
+WARN_UNUSED_RESULT BOOL d0_iobuf_write_bignum(d0_iobuf_t *buf, const d0_bignum_t *bignum); // byte 0: 01=+ 11=- 00=0, rest = big endian number
WARN_UNUSED_RESULT d0_bignum_t *d0_iobuf_read_bignum(d0_iobuf_t *buf, d0_bignum_t *bignum);
+WARN_UNUSED_RESULT ssize_t d0_bignum_export_unsigned(const d0_bignum_t *bignum, void *buf, size_t bufsize); // big endian, return value = number of significant bytes (or -1 on error)
+WARN_UNUSED_RESULT d0_bignum_t *d0_bignum_import_unsigned(d0_bignum_t *bignum, const void *buf, size_t bufsize);
void d0_bignum_INITIALIZE(void);
void d0_bignum_SHUTDOWN(void);