LAWS.kbkdf_counter_stream_length: law of bend-osdev-crypto@0.1.0.0
Import: import bend-osdev-crypto@0.1.0.0/LAWS.bend as LAWS
Lines 548-561 of bend-osdev-crypto@0.1.0.0/LAWS.bend: https://jend.leeeet.dev/read.txt?path=bend-osdev-crypto@0.1.0.0/LAWS.bend&start_line=548&end_line=561

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

# SP 800-108 KDFs over any MAC (kbkdf.bend), for every MAC, key, fixed
# input data and length: each stream has the length asked for, a shorter
# stream is a prefix of a longer one with the same fixed input (and IV), and
# a derivation that succeeds has the length asked for. (The interface's
# prefix law holds of the streams: a derivation binds its length L into
# the fixed input, so derivations of two lengths differ.)
law kbkdf_counter_stream_length:
  for ~K: Data
  for ~compute: K -> B.Octets -> B.Octets
  for ~rlen: Nat
  for +k: K
  for +fixed: B.Octets
  for +n: Nat
  {B.Octets.len(Kb.CrKbkdf.counter_stream(~K, ~compute, ~rlen, k, fixed, n)) == n : Nat}

Uses (11):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  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=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.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=len
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-crypto@0.1.0.0/PROOF.bend&name=kb_ctr_len
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-crypto@0.1.0.0/PROOF.bend&name=octets_len_of
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-crypto@0.1.0.0/kbkdf.bend&name=CrKbkdf.counter_stream
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-crypto@0.1.0.0/kbkdf.bend&name=cr.kb.ctr