Check.flip_last: def of bend-osdev-crypto@0.1.0.0
Import: import bend-osdev-crypto@0.1.0.0/check.bend as Check
Lines 224-227 of bend-osdev-crypto@0.1.0.0/check.bend: https://jend.leeeet.dev/read.txt?path=bend-osdev-crypto@0.1.0.0/check.bend&start_line=224&end_line=227

import Base
import bend-osdev-bytes@0.1.0.0/bytes.bend as B

# CMAC-AES through the MAC interface: the tag, and whether verify accepts it
# and refuses it with its last byte changed
def flip_last(+t: B.Octets) -> B.Octets:
  B.Octets.append(B.Octets.take(Nat.sub(B.Octets.len(t), 1n), t), B.Octets.of_list([U32.xor(Maybe.default(&2, U32, B.Octets.at(t, Nat.sub(B.Octets.len(t), 1n)), 0), 1)]))

Uses (11):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe.default
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub
  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
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets.append
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets.at
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets.len
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets.of_list
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets.take