     assert Matasano.repeating_xor(key, message) == output
   end
 
+  @tag :set1
   test "set 1 challenge 6 - break repeating-key xor" do
     data = Matasano.IO.bytes_from_base64(Path.join("data", "6.txt"))
     key = "Terminator X: Bring the noise"

  use ExUnit.Case, async: true
  doctest Matasano

  test "set 1 challenge 1 - convert hex to base64" do
    hex = "49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d"
    base64 = "SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t"

    assert Matasano.hex_to_base64(hex) == base64
  end

  @tag :set1
  test "set 1 challenge 2 - fixed xor" do
    a = Base.decode16!("1c0111001f010100061a024b53535009181c", case: :lower)
    b = Base.decode16!("686974207468652062756c6c277320657965", case: :lower)
