BIGN_SIGLEN
#define BIGN_MAX_SIGLEN BIGN_SIGLEN(CURVES_MAX_Q_BIT_LEN)
(*siglen) = (u8)BIGN_SIGLEN(q_bit_len);
MUST_HAVE((siglen == BIGN_SIGLEN(q_bit_len)), ret, err);
MUST_HAVE((siglen == BIGN_SIGLEN(q_bit_len)), ret, err);