def ccmp.len_xc

bend-osdev-cipher-modes@0.1.0.0 · PROOF.bend:1812

import Base
import bend-osdev-bytes@0.1.0.0/bytes.bend as B
import bend-osdev-cipher-modes@0.1.0.0/cipher_modes.bend as M
import bend-osdev-cipher-modes@0.1.0.0/ccm.bend as CC

1812# and keeps its length
1813def ccmp.len_xc(~K: Data, ~enc: K -> M.CmBlock -> M.CmBlock, +k: K, +a0: M.CmBlock, +ys: List<&2, U32>) -> {B.len(CC.ccm.xcrypt(~K, ~enc, k, a0, M.cm.split(B.mask(ys)))) == B.len(B.mask(ys)) : Nat}:
1814  %sp.eta(M.cm.split(B.mask(ys))) : {B.len(CC.ccm.xcrypt(~K, ~enc, k, a0, _)) == B.len(B.mask(ys)) : Nat}
1815  %sp.join_split(ys) : {B.len(M.cm.join_onto(CC.ccm.ctrb(~K, ~enc, k, M.cm.split.blocks(M.cm.split(B.mask(ys))), a0, 1), M.cm.xor_bytes(M.cm.split.tail(M.cm.split(B.mask(ys))), M.cm.bytes_of(enc(k, CC.ccm.ai(a0, U32.add(1, U32.from_nat(List.length(&2, M.CmBlock, M.cm.split.blocks(M.cm.split(B.mask(ys)))))))))))) == B.len(_) : Nat}
1816  ccmp.len_join(~K, ~enc, k, M.cm.split.blocks(M.cm.split(B.mask(ys))), a0, 1, M.cm.xor_bytes(M.cm.split.tail(M.cm.split(B.mask(ys))), M.cm.bytes_of(enc(k, CC.ccm.ai(a0, U32.add(1, U32.from_nat(List.length(&2, M.CmBlock, M.cm.split.blocks(M.cm.split(B.mask(ys)))))))))), M.cm.split.tail(M.cm.split(B.mask(ys))), li.len_xor(M.cm.split.tail(M.cm.split(B.mask(ys))), M.cm.bytes_of(enc(k, CC.ccm.ai(a0, U32.add(1, U32.from_nat(List.length(&2, M.CmBlock, M.cm.split.blocks(M.cm.split(B.mask(ys))))))))))(na.lt_le(B.len(M.cm.split.tail(M.cm.split(B.mask(ys)))), 16n)(sp.tail_short(ys))))