def cr.xcbc.go

bend-osdev-crypto@0.1.0.0 · xcbc.bend:55

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

55# the CBC-MAC over the pieces from E = e; the last piece is whole or short
56def cr.xcbc.go(~K: Data, ~Blk: Data, ~bsize: Nat, ~enc: K -> Blk -> Blk, ~blk_of: B.Octets -> Maybe<&2, Blk>, ~blk_to: Blk -> B.Octets, +k1: K, +k2: B.Octets, +k3: B.Octets, ps: List<&2, List<&2, U32>>, +e: B.Octets) -> B.Octets:
57  match ps:
58    case Nil{}:
59      cr.xcbc.e(~K, ~Blk, ~enc, ~blk_of, ~blk_to, k1, O.CrOct.xor(cr.xcbc.full(False{}, bsize, k2, k3, B.Octets.empty()), e))
60    case Con{p, t}:
61      match t:
62        case Nil{}:
63          +po = B.Octets.of_list(p)
64          cr.xcbc.e(~K, ~Blk, ~enc, ~blk_of, ~blk_to, k1, O.CrOct.xor(cr.xcbc.full(Nat.is_eq(B.Octets.len(po), bsize), bsize, k2, k3, po), e))
65        case Con{q, u}:
66          cr.xcbc.go(~K, ~Blk, ~bsize, ~enc, ~blk_of, ~blk_to, k1, k2, k3, Con{q, u}, cr.xcbc.e(~K, ~Blk, ~enc, ~blk_of, ~blk_to, k1, O.CrOct.xor(B.Octets.of_list(p), e)))