- /// Construct the invoice's HRP and signatureless data into a preimage to be hashed.
- pub(crate) fn construct_invoice_preimage(hrp_bytes: &[u8], data_without_signature: &[u5]) -> Vec<u8> {
- use bech32::FromBase32;
-
- let mut preimage = Vec::<u8>::from(hrp_bytes);
-
- let mut data_part = Vec::from(data_without_signature);
- let overhang = (data_part.len() * 5) % 8;
- if overhang > 0 {
- // add padding if data does not end at a byte boundary
- data_part.push(u5::try_from_u8(0).unwrap());
-
- // if overhang is in (1..3) we need to add u5(0) padding two times
- if overhang < 3 {
- data_part.push(u5::try_from_u8(0).unwrap());
- }
- }
-
- preimage.extend_from_slice(&Vec::<u8>::from_base32(&data_part)
- .expect("No padding error may occur due to appended zero above."));
- preimage
- }
-