anchor.diff:  let disambiguate (b: byte, bs: byte []) : byte [] =
       let rec check pairs =
           match pairs with
  -            | []        -> [|b|]
  +            | []       -> Utils.xorArr [|b|] [|1uy|]
               | (n,x)::_ -> if paddingOracle x = false then check (List.tail pairs)
  -                          else genBlock x n        
  +                          else genBlock x n
       [ for i in [1..15] do
             yield (i+1, Array.concat [| bs.[0..(15-i-1)];
                                         Utils.xorArr [|bs.[(15-i)]|] [|1uy|] 
  
positive.code: 
  let genGuesses (code: byte []) s offset (found: byte []): (byte * byte []) list =
      let guessByte n =
          Utils.xorArrs [ [|code.[s+offset]|]; [|byte n|]; [|byte (16-offset)|] ]
      let padding n = Utils.repeat (byte n) |> Seq.take (n-1) |> Seq.toArray
      let foundBytes =
          let f = Utils.xorArrs [ code.[s+offset+1..s+15]; padding (16-offset); found ]
          printfn "%A" f
          f
      let genGuess i: byte [] =
          Array.concat [| code.[s..(s+offset-1)];
  
negative.code:     |> evalGuesses offset
      |> fst
      |> Array.create 1
      |> Utils.xorArr [|byte (16 - offset)|]
  
  let rec decryptBlock start offset (found: byte []) (code: byte []): byte [] =
      match offset with
  