pub fn begin_rmac_session(data: &[u8]) -> Result<Capdu, BuildError>Expand description
Build a BEGIN R-MAC SESSION (CLA 80, INS 7A) plaintext C-APDU.
data is the caller’s optional R-MAC challenge, sent LV-coded (len ‖ data)
and folded into the card’s R-MAC. It must be 1..=24 bytes.
§Errors
BuildError::Overflow if data is empty or longer than 24 bytes.