Mac.mask: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/src/crypto/mac.bend as Mac
Lines 42-53 of bend-collections-laws-crypto@1.0.0.0/src/crypto/mac.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/mac.bend&start_line=42&end_line=53

import Base

# The n-byte block (key zero-padded to n bytes) XOR the pad byte, in one
# pass: past the end of the key a byte is 0 XOR pad = pad.
def mask(key: List<&2, U32>, n: Nat, +pad: U32) -> List<&2, U32>:
  match key n:
    case Nil{} 0n:
      Nil{}
    case Nil{} 1n+p:
      pad <> mask(Nil{}, p, pad)
    case k <> rest 0n:
      Nil{}
    case k <> rest 1n+p:
      U32.xor(k, pad) <> mask(rest, p, pad)

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.xor